Introducing Computer Hardware

The term hardware refers to the computer’s physical components, such as the monitor, keyboard, motherboard, and hard drive. The term software refers to the set of instructions that directs the hardware to accomplish a task. To perform a computing task, software uses hardware for four basic functions: input, processing, storage, and output.

HARDWARE USED FOR INPUT AND OUTPUT: Most input/output devices are outside the computer case. These devices communicate with components inside the computer case through a wireless connection or through cables attached to the case at a connection called a port. Most computer ports are located on the back of the case, but some cases have ports on the front for easy access. The most popular input devices are a keyboard and a mouse, and the most popular output devices are a monitor and a printer.

HARDWARE INSIDE THE COMPUTER CASE :


A motherboard containing the CPU, memory, and other components




A hard drive and optical drive (CD or DVD) used for permanent & removable storage




A power supply with power cords supplying electricity to all devices inside the case




Adapter cards used by the CPU to communicate with devices inside and outside the case




Cables connecting devices to adapter cards and the motherboard

THE MOTHER BOARD The largest and most important circuit board in the computer is the motherboard, also called the main board, the system board. The motherboard contains a socket to hold the CPU; the CPU is the component in which most processing takes place. All devices in a computer are either installed directly on the motherboard, directly linked to it by a cable connected to a port on the motherboard, or indirectly linked to it by expansion cards. A device that is not installed directly on the motherboard is called a “peripheral device”.

Components used primarily for processing:


Processor or CPU (central processing unit), the computer’s mostly important chip.




Chipset that supports the processor by controlling many motherboard activities.




RAM (random access memory), used for temporary storage which holds data and instructions as they are processed.

……Components that allow the processor to communicate with other devices:


Expansion slots to connect expansion cards to the motherboard




The system clock that keeps communication in sync




Connections for data cables to devices inside the case




Ports for devices outside the case

The electrical system consists of: Power supply connections that provide electricity to the motherboard

and expansion cards

Programming and setup data stored on:


Flash ROM, a memory chip used to permanently store instructions that control basic hardware functions.




CMOS RAM and CMOS setup chip that holds configuration data

Ports of motherboard to the outside of the case:


Keyboard port, a mouse port, a parallel port, two S/PDIF sound ports (for optical or coaxial cable), a FireWire port, a network port, four USB ports, six sound ports, and a wireless network antenna port.




A parallel port transmits data in parallel and is most often used by older printer.




An S/PDIF (Sony-Philips Digital Interface) sound port connects to an external home theater audio system,

providing digital output and the best signal quality.


A FireWire port (IEEE 1394) is used for high-speed multimedia devices such as digital camcorders.




A universal serial bus (USB) port can be used by many different input/output devices, such as keyboards, printers, scanners, and digital cameras.




In addition to these ports, some older motherboards provide a serial port that transmits data serially, used for an external modem or printer.

THE PROCESSOR AND THE CHIPSET: The processor or CPU is the chip inside the computer that performs most of the actual data processing. The processor could not do its job without the assistance of the chipset, a group of microchips on the motherboard that control the flow of data and instructions to and from the processor. The chipset is responsible for the careful timing and coordination of activities. The chipset is an integrated component of the motherboard.

STORAGE DEVICES

In Figure you saw two kinds of storage: temporary and permanent. The processor uses temporary storage, called primary storage or memory, to temporarily hold both data and instructions while it is processing them. However, when data and instructions are not being used, they must be kept in permanent storage, sometimes called secondary storage, such as a hard drive, CD, DVD, or USB drive. Primary storage is much faster to access than permanent storage.

………PRIMARY STORAGE

……...SECONDARY STORAGE Data and instructions are permanently stored on devices, such as DVDs, CDs, hard drives, and USB drives, in locations that are remote from the CPU. Data and instructions cannot be processed by the CPU from this remote storage (called secondary storage), but must first be copied into primary storage (RAM) for processing. The most important difference between primary and secondary storage. When you turn off your computer, the information in secondary storage remains intact. Secondary storage devices are often grouped in these three categories: hard drives, optical drives & removable storage.

Hard Drives: Hard drives consist of a sealed case containing platters or disks that rotate at a high speed. As the platters rotate, an arm with a sensitive read/write head reaches across the platters, both writing new data to them and reading existing data from them. The data is written as magnetic spots on the surface of each platter. These magnetic hard drives use an internal technology called Integrated Drive Electronics (IDE). A newer technology for hard drives uses non-volatile flash memory chips, is called a solid state drive (SSD). SSD drives have no moving parts, they are much faster, more rugged, consume less power, last longer, and more expensive than magnetic drives. The interface between an internal hard drive and the motherboard is likely to conform to an ATA (AT Attachment) standard, as published by the American National Standards Institute (ANSI). The two major ATA standards for a drive interface are serial ATA (SATA) and parallel ATA (PATA).

Optical Drives: An optical drive is considered standard equipment on most computer systems today because most software is distributed on CDs, DVDs and Blu-ray Disc (BD).

USB Flash Drives and Memory Cards: Two popular removable storage devices are USB flash drives (also called thumb drives) and memory cards commonly used with digital cameras. Both types of devices use non-volatile flash memory chips.

Floppy Disk Drives: An older secondary storage device sometimes found inside the case is a floppy drive (FDD), that can hold 3.5-inch disks containing up to 1.44 MB of data.

Expansion Slot: PCI (Peripheral Component Interconnect) expansion slot used for input/output devices. PCI Express (PCIe) slots that come in several lengths and are used by high-speed input/output devices. AGP (Accelerated Graphics Port) expansion slot used for a video card

Expansion cards: Expansion cards are mounted in expansion slots on the motherboard

THE ELECTRICAL SYSTEM (SMPS): The most important component of the computer’s electrical system is the power supply. This power supply converts and reduces voltage that the computer can handle. A power supply receives 110–230 volts of AC power from a wall

outlet and converts it to a much lower DC voltage. Older power supplies had power cables that provided either 5 or 12 volts DC. Newer power supplies provide 3.3, 5, and 12 volts DC. In addition to providing power for the computer, the power supply runs a fan directly from the electrical output voltage to help cool the inside of the computer.

INSTRUCTIONS STORED ON THE MOTHERBOARD : Some very basic instructions are stored on the motherboard—just enough to start the computer, use some simple hardware devices such as a monitor and keyboard, and search for an operating system stored on a storage device such as a hard drive or CD. These data and instructions are stored on special ROM (read-only memory) chips on the board and are called the BIOS (basic input/output system).

This software is actually a part of the hardware and is not easily changed. Software embedded into hardware is often referred to as firmware because of its hybrid nature. The motherboard ROM BIOS serves three purposes: The BIOS that is sometimes used to manage simple devices is called system BIOS, the BIOS that is used to start the computer is called startup BIOS, and the BIOS that is used to change some settings on the motherboard is called BIOS setup or CMOS setup. These motherboard settings are stored in a small amount of RAM located on the firmware chip. Settings stored in CMOS RAM include such things as the current date and time, which hard drives are present, boot order etc. When the computer is first turned on, it looks to settings in CMOS RAM to find out what hardware it should expect to find. CMOS RAM is volatile memory. When the computer is turned off, CMOS RAM is powered by a trickle of electricity from a small battery. Motherboard manufacturers often publish updates for the ROM BIOS on their motherboards; if a board is giving you problems or you want to use a new feature just released, you might want to upgrade the BIOS. In the past, this meant buying new ROM chips and exchanging them on the motherboard. However, ROM chips on motherboards today are made of non-volatile memory and can be reprogrammed. Called flash ROM, the software stored on these chips can be overwritten by new software that remains on the chip until it is overwritten.

Summary:


A computer requires both hardware and software to work.




The four basic functions of the microcomputer are input, output, processing, and storage of data.




Data and instructions are stored in a computer in binary form, which uses only two states for data—on and off, or 1 and 0—which are called bits. Eight bits equal one byte.




The four most popular input/output devices are the mouse, keyboard, printer, and monitor.




The most important component inside the computer case is the motherboard, also called the main board or system board. It holds the most important microchip inside the case, the central processing unit (CPU), a microprocessor or processor. The motherboard also gives access to other circuit boards and peripheral devices.All communications between the CPU and other devices must pass through the motherboard.




Devices outside the computer case connect to the motherboard through ports on the case. Common ports are network, FireWire, sound, serial, parallel, USB, keyboard, and mouse ports.




An adapter card inserted in an expansion slot on the motherboard can provide an interface between the motherboard and a peripheral device, or can itself be a peripheral. (An example is a network card.)




The chipset on a motherboard controls most activities on the motherboard.




Primary storage, called memory or RAM, is temporary storage the CPU uses to hold data and instructions while it is processing both.




Secondary storage is slower than primary storage, but it is permanent storage. Some examples of secondary storage devices are hard drives, CD drives, DVD drives, Blu-ray drives, flash drives, memory cards, Zip drives, and floppy drives.




Most older hard drives, CD drives, and DVD drives use the parallel ATA (PATA) interface standard, also called the EIDE (Enhanced Integrated Drive Electronics) standard, which can accommodate up to four EIDE or IDE devices on one system. Newer drives use the serial ATA (SATA) interface standard.




A motherboard can have several buses, including the system bus, the PCI Express bus, the PCI bus, and the older AGP bus.




The power supply inside the computer case supplies electricity to components both inside and outside the case. Some components external to the case get power from their own electrical cables.




A ROM BIOS or firmware microchip is a hybrid of hardware and software containing programming embedded into the chip to start a PC and begin the process of loading an operating system.




The BIOS setup program is part of ROM BIOS stored on the firmware chip. This program is used to change motherboard settings or configuration information.

Motherboards

INTRODUCTION: A motherboard is the most complicated component in a computer. When you put together a computer from parts, generally you start with deciding on which processor and motherboard you will use. you’d need to pay attention to form factor, processor sockets, chipsets, buses and number of bus slots, and other connectors, slots, and port.

MOTHERBOARD FORM FACTORS: The most popular motherboard form factors are ATX, Micro ATX, Flex ATX, BTX, ITX and NLX.

ATX Motherboard:

Micro-ATX motherboard by Bio star has an AM2 socket that supports an AMD processor:

BTX motherboard with an LGA 775 socket that supports an Intel processor:

PROCESSOR SOCKETS: Another important feature of a motherboard is the processor socket. This socket and the chipset determine which processors a board can support. A socket will hold either an Intel or AMD processor. Some older processors were installed on the motherboard in a long narrow slot, but all processors sold today use sockets. Earlier Pentiums used a pin grid array (PGA) socket, with pins aligned in uniform rows around the socket. Later sockets used a staggered pin grid array (SPGA), with pins staggered over the socket to squeeze more pins into a small space. Small pins can easily be bent as the processor is installed in the socket. Later Intel sockets use a land grid array (LGA) that uses lands rather than pins. PGA, SPGA, and LGA sockets are all square or nearly square. So that even force is applied when inserting the processor in the socket, all current processor sockets have a lever on the side of the socket. These sockets are called zero insertion force (ZIF) sockets. It is not likely to support every processor that uses its socket because the mother board chipset is designed to only work with certain processors.

Socket LGA775 is the first Intel socket to use lands rather than pins:

Socket LGA1366 is the latest Intel socket used by desktop, workstation, and low-end server systems:

AMD Athlon 64 processor to be inserted into an AM2+ socket:

THE CHIPSET: High-performance chip sets: The X58 chipset supports the Intel LGA1366 socket, the Core i7 processors, and PCI Express Version 2. It can also support either SLI or Cross Fire technologies. (SLI and Cross Fire are two competing technologies that allow for multiple video cards installed in one system.) The X58 chipset does not control memory because the memory controller is embedded in the Core i7 processor. The 975X Express chipset supports the Pentium Extreme Edition processor, multiple video cards, and up to 8 GB of memory.

Mainstream desktop chip sets: The P45, P43, P35, G45, and G31 chipsets support Core 2 Quad and Core 2 Duo Intel processors. P45, P43, and G45 can support up to 16 GB of DDR3 or DDR2 memory. The P35 chipset supports up to 8 GB of DDR3 or DDR2 memory. It also supports the Core 2 Extreme processor. The G31 chipset supports up to 4 GB of DDR2 memory. The Q45 chipset uses DDR3 or DDR2 memory and supports the Core

2 Duo and Core 2 Quad processors. All these chipsets use socket LGA775.

Value desktops:

The 910GL, 845E, 845G, and 865G chipsets support the Pentium 4,Celeron, and Celeron D processors in low-end systems. The 910GL chipset uses the LGA775 socket. The 845E, 845G, and 865G chipsets use the 478PGA socket. All these chipsets use DDR memory.

Older value desktops:

The 845 and 845GL chipsets support the Pentium 4 or Celeron processors in a lowend system using the 478PGA socket. They support up to 2 GB of DDR memory. Beginning with the Intel i800 series of chipsets, a hub is used to connect buses. All I/O buses (input/output buses) connect to a hub, which connects to the system bus. This hub is called the hub interface, and the architecture is called Accelerated Hub Architecture. The fast end of the hub, which contains the graphics and memory controller, connects to the system bus and is called the hub’s North Bridge. The slower end of the hub, called the South Bridge, contains the I/O controller hub. All I/O devices, except display and memory, connect to the hub by using the slower South Bridge. With previous Intel chipsets, the memory controller was part of the North Bridge, but the Core architecture processor contains the memory controller within the processor so memory connects directly to the processor rather than to the North Bridge.

North Bridge and South Bridge control access to the processor for all components:

X58 chipset architecture:

BUSES AND EXPANSION SLOTS: Electrical power: Chips on the motherboard require power to function. These chips tap into a bus’s power lines and draw what they need. Control signals. Some wires on a bus carry control signals that coordinate all the activity. Memory addresses: Components pass memory addresses to one another, telling each other where to access data or instructions. The number of wires that make up the memory address lines of the bus determines how many bits can be used for a memory address. The number of wires thus limits the amount of memory the bus can address. Data:

Data passes over a bus in a group of wires, just as memory addresses do. The number of lines in the bus used to pass data determines how much data can be passed in parallel at one time. The number of lines depends on the type of processor and determines the number of bits in the data path. (Remember that a data path is the part of the bus on which the data is placed; it can be 8, 16, 32, 64, or more bits wide.)

THE PCI BUS: PCI: (Peripheral Component Interconnect) buses have been improved several times; there are currently three major categories and within each category, several variations of PCI.

PCI-X: The next evolution of PCI is PCI-X, which has had three major revisions; the latest is PCI-X 3.0. All PCI-X revisions are backward compatible with conventional PCI cards and slots, except 5-V PCI cards are no longer supported. PCIX is focused on technologies that target the server market; therefore, it’s unlikely you’ll see PCI-X slots in desktop computers. Motherboards that use PCI-X tend to have several different PCI slots with some 32-bit or 64-bit slots running at different speeds.

PCI Express: PCI Express (PCIe) uses an altogether different architectural design than conventional PCI and PCI-X; PCIe is not backward compatible with either. PCI Express will ultimately replace both these buses as well as the AGP bus, although it is expected PCI Express will coexist with conventional PCI for some time to come (see Figure 5-14). Whereas PCI uses a 32-bit or 64-bit parallel bus, PCI Express uses a serial bus, which is faster than a parallel bus because it transmits data in packets similar to how an Ethernet network, USB, and FireWire transmit data. A PCIe expansion slot can provide one or more of these serial lanes.

The two long PCI-X slots can support PCI cards :

PCI Express slot for a PCIe card has its own link or bus to the South Bridge, and one PCI Express slot has a direct link to the faster memory controller hub or North Bridge. This last PCI Express slot is intended to be used by a PCIe video card.

8-pin PCIe Version 2.0 power connector:

THE AGP BUSES: Motherboard video slots and video cards used the Accelerated Graphics Port (AGP) standards for many years, but AGP has mostly been replaced by PCI Express. Even though AGP is a dying technology, you still need to know how to support it. A motherboard will have a PCI Express x16 slot or an AGP slot, but not

both.

This motherboard uses an AGP 3.3-V slot, which accommodates an AGP 1.0 video card:

ON-BOARD PORTS AND CONNECTORS: In addition to expansion slots, a motherboard might also have several on-board ports and internal connectors. Ports coming directly off the motherboard are called on-board ports or integrated components. Almost all motherboards have two or more USB ports and sound ports. Boards might also offer a network port, modem port, FireWire (IEEE 1394) port, video port, keyboard port, mouse port, parallel port, serial port, one or more eSATA ports (for external SATA hard drives), and a port for a wireless antenna.

HARDWARE CONFIGURATION: Settings on the motherboard are used to enable or disable a connector or port, set the frequency of the CPU, system bus, or other buses, control security features, and control what happens when the PC first boots. In the past, configuring these and other motherboard settings was done in three different ways: DIP switches, jumpers, and CMOS RAM.

SETUP DATA STORED BY DIP SWITCHES: Some older motherboards and expansion cards store setup data using a dual inline package (DIP) switch, as shown in Figure 5-27. A DIP switch has an ON position and an OFF position.

USING THE BIOS JUMPERS ON THE MOTHERBOARD: Most motherboards today have a group of BIOS jumpers that can be used to recover from a failed BIOS update or forgotten power-on password. For example, Figure 5-40 shows a group of three jumpers on one board. (The tan jumper cap is positioned on the first two jumper pins on the left side of the group.) Figure 5-41 shows the motherboard documentation on how to use these jumpers. When jumpers 1 and 2 are closed, which they are in the figure, normal booting happens. When jumpers 2 and 3 are closed, passwords to BIOS setup can be cleared on the next boot. When no jumpers are closed, on the next boot, the BIOS will recover itself from a failed update.

INSTALLING OR REPLACING A MOTHERBOARD: When you purchase a motherboard, the package comes with the board, I/O shield, documentation, drivers, and various screws, cables, and connectors (see Figure 5-42). When you replace a motherboard, you pretty much have to disassemble an entire computer, install the new motherboard, and reassemble the system.

Auxiliary power connectors to support PCIe:

Seven connectors from the front panel connect to the motherboard:

HOW TO SELECT A MOTHER BOARD: 1. what form factor does the motherboard use? 2. Does the motherboard support the number and type of processor you plan to use (for example, Socket LGA 775 for the Intel Pentium Dual Core processor up to 3.3GHz)? 3. What are the supported frequencies of the system bus (for example, 1066/800/533 MHz)? 4. What chipset does the board use? 5. What type of memory does the board support (DDR2 or DDR3), and how much memory can the board hold? 6. What type and how many expansion slots are on the board (for example, PCI, PCI Express 2.0, or AGP)? 7. What hard drive controllers and connectors are on the board (for example, IDE, serial ATA, RAID, and SCSI)? 8. What are the embedded devices on the board, and what internal slots or connections does the board have? (For example, the board might provide a network port, wireless antenna port, FireWire port, two or more USB ports, mouse port, and so forth.) 9. Does the board fit the case you plan to use? 10. What are the price and the warranty on the board? 11. How extensive and user-friendly is the documentation? 12. How much support does the manufacturer supply for the board?

SUMMARY:


The motherboard is the most complicated of all components inside the computer. It contains the processor and accompanying chipset, real-time clock, ROM BIOS, CMOS configuration chip, RAM, system bus, expansion slots, jumpers, ports, and power supply connections. The motherboard you select determines both the capabilities and limitations of your system.




The most popular motherboard form factors are ATX, MicroATX, FlexATX, BTX, and NLX, in that order.




A motherboard will have one or more Intel sockets for an Intel processor or one or more AMD sockets for an AMD processor.




Intel, AMD, NVIDIA, and SiS are the most popular chipset manufacturers. The chipset embedded on the motherboard determines what kind of processor and memory the board can support.




Two or more video cards installed on a motherboard use NVIDIA SLI or ATI Cross Fire technology.




Buses used on motherboards include conventional PCI, PCI-X, PCI Express, and AGP. AGP is used solely for video cards. PCI Express has been revised three times and is expected to replace all the other bus types.




Some components can be built in to the motherboard, in which case they are called on-board components. Other components can be attached to the system in some other way, such as on an expansion card.




A bus is a path on the motherboard that carries electrical power, control signals, memory addresses, and data to different components on the board.




The most common method of configuring components on a motherboard is BIOS setup. Some motherboards also use jumpers or DIP switches to contain configuration Settings.




Sometimes ROM BIOS programming stored on the firmware chip needs updating or refreshing. This process is called updating BIOS or flashing BIOS.




When installing a motherboard, first study the motherboard and set jumpers and DIP switches on the board. Sometimes the processor and cooler are best installed before installing the motherboard in the case. When the cooling assembly is heavy and bulky, it is best to install it after the motherboard is securely seated in the case.

Processors

The processor installed on a motherboard is the primary component that determines the computing power of the system. The two major manufacturers of processors are Intel and AMD.

Processors are rated based on several features that affect performance and the motherboards that can support them. These features are listed here: Feature 1:The system bus speeds the processor supports. Current Intel processors work with system buses that run at 1600, 1333, 1066, or 800 MHz. Current AMD processors work with system buses that run at 1800, 1000, or 800 MHz. Feature 2: Processor core frequency is measured in gigahertz, such as 3.2 GHz. Feature 3: The motherboard socket and chipset the processor can use. Current Intel sockets for desktop systems are the LGA1366, LGA1155,LGA 775, and PGA478 sockets. AMD’s current desktop sockets are AM3, AM2+, AM2,754, and 940 sockets.

Feature 4: Multiprocessing ability, which is the ability of a system to do more than one thing at a time. This is accomplished by several means, including two processing units installed within a single processor (first used by Pentium processors), a motherboard using two processor sockets, and multiple processors installed in the same processor housing (called dual-core, quad-core, or octo-core processing). Feature 5: The amount of memory included with the processor, called a memory Cache. Memory on the processor die is called Level 1 cache (L1 cache). Memory in the processor package, but not on the processor die, is called Level 2 cache (L2 cache).Some processors use a third cache farther from the processor core, but still in the processor package, which is called Level 3 cache (L3 cache).

Feature 6: The amount and type of memory (DDR, DDR2, or DDR3) installed on the motherboard that the processor can support. Feature 7: Computing technologies the processor can use. Probably the best-known technologies used by processors are Intel’s Hyper-Threading and AMD’s Hyper Transport. Both allow each logical processor within the processor package to handle an individual thread in parallel with other threads being handled by other processors within the package.

Feature 8: The voltage and power consumption of the processor. Today’s processors have technologies that put the processor in a sleep state when they are inactive and reduce voltage requirements and CPU frequency depending on the demands placed on the processor. Intel calls this technology Enhanced Intel Speed Step Technology (EIST) and AMD uses Power Now!

HOW A PROCESSOR WORKS WORKS:: A processor contains three basic components: an input/output (I/O) unit, a control unit, and one or more arithmetic logic units (ALUs). The I/O unit manages anages data and instructions entering and leaving the processor. The control unit manages all activities inside the processor itself. The ALU does all logical comparisons and calculations. Registers are small holding areas on the processor chip that work much as RAM does outside the processor. Registers hold counters, data, instructions, and addresses that the ALU is ccurrently urrently processing. In addition to registers, the processor has its own internal memory caches (L1, L2, and possibly L3) that hold data and instructions waiting to be processed by the ALU.

PROCESSOR FREQUENCY OR SPEED SPEED: Processor frequency is the speed at which the processor operates internally. If the processor operates at 3.2 GHz internally but 800 MHz externally, the processor frequency is 3.2 GHz, and the system bus frequency is 800 MHz. In this case, the processor operates at four times the system bus frequency. This factor is called the multiplier. If you multiply the system bus frequency by the multiplier, you get the processor frequency: System bus frequency x multiplier = processor frequency frequency..

Overclocking: For most motherboards and processors, you can override the default frequencies by changing a setting in BIOS setup. Running a motherboard rd or processor at a higher speed than the manufacturer suggests is called overclocking and is not recommended because the speed is not guaranteed to be stable. Also, know that running a processor at a higher-than-recommended recommended speed can result in overheatin overheating, g, which can damage the processor. Dealing with overheating is a major concern when overclocking a system. And warranties for the motherboard or processor are sometimes voided when they are overclocked. Most motherboards and processors offer some protection against overheating so that, if the system overheats, it will throttle down or shut down to prevent the processor from being damaged per permanently.

MULTIPROCESSING, MULTIPLE PROCESSORS, AND MULTI MULTI-CORE CORE PROCESSING: Multiprocessing: It is accomplished when a processor contains more than one ALU. Older processors had only a single ALU. Pentiums, and those processors coming after them, have at least two ALUs. With two ALUs, processors can process two instructions at once and, therefore, are true multiprocessing processors.

Multiprocessor platform: It improves performance by installing more than one processor on a motherboard. A motherboard must be designed to support more than one processor by providing more than one processor socket.

Multi-Core processing: It contains two or more cores that operate at the same frequency, but independently of each other. Each core is a logical processor which contains two ALUs; therefore, each core can process two instructions at once. A CPU using multi-core processing can have two cores (dual core supporting four instructions at once), three cores (triple core supporting six instructions at once), four cores (quad core supporting eight instructions at once), or eight cores (octo core supporting sixteen instructions at once).

MEMORY CACHE AND THE MEMORY CONTROLLER: A memory cache, such as an L1, L2, or L3 cache, is RAM that holds data and instructions that the memory controller anticipates the processor will need next. Using a cache improves performance because the controller does not have to make as many calls to RAM on the motherboard to fetch data or instructions. Performance also improves because RAM stored in memory modules (DIMMs) on the motherboard is Dynamic RAM or DRAM (pronounced “D-Ram”) and memory in a memory cache is Static RAM or SRAM (pronounced “S-Ram”). Dynamic RAM loses data rapidly and must be refreshed often. SRAM does not need refreshing and can hold its data as long as power is available.

Cache memory (SRAM) is used to temporarily hold data in expectation of what the processor will request next:

TECHNOLOGIES THE PROCESSOR CAN USE: Groups of instructions that accomplish fundamental operations, such as comparing or adding two numbers, are permanently built into the processor chip. These instructions are called microcode and the groups of instructions are collectively called the instruction set. Intel calls these instruction sets its instruction set architecture (ISA).

Here is a list of computing technologies you might expect to see a processor support: 1. MMX (Multimedia Extensions): It was the first technology to support repetitive looping, whereby the processor receives an instruction and then applies it to a stream of data that follows. Prior to MMX, each data set had to be preceded by an instruction to process it. MMX helps with processing multimedia data, which includes a lot of repetition when managing audio and graphics data.

2. SSE (Streaming SIMD Extension): It was an improvement over MMX. SIMD stands for “single instruction, multiple data.” As with MMX, it allows the CPU to receive a single instruction and then execute it on multiple pieces of data. SSE also improves on 3D graphics.

3. 3DNow! by AMD is a processor instruction set designed to improve performance with 3D graphics and other multimedia data.

4. SSE2 has a larger instruction set than SSE, and SSE3 improves on SSE2 SSE4: It increases the instruction set to improve 3D imaging for gaming and improve performance with data mining applications.

5. Intel Hyper-Threading and AMD Hyper Transport: allow each processor within a processor package to handle its own individual thread in parallel with other threads being processed at the same time.

6. Power Now! by AMD increases performance and lowers power requirements. 7. Cool ’n’ Quiet by AMD lowers power requirements and keep a system quiet. 8. Enhanced Intel Speed Step Technology (EIST) by Intel steps down processor frequency when the processor is idle to conserve power and lower heat.

9. Execute Disable Bit by Intel is a security feature that prevents software from executing or reproducing itself if it appears to be malicious. 10. IntelEM64T (Extended Memory 64 Technology) processors are also known as x86-64bit

processors. All desktop and notebook processors sold today are hybrid processors that can support either 32-bit or 64-bit computing.

11. Intel Turbo Boost Technology provides more performance when needed. Intel® Turbo Boost Technology automatically allows processor cores to run faster than the base operating frequency

12. Intel Quick Sync Video Quickly convert and share videos faster with Intel® Quick Sync Video.

INTEL PROCESSORS

AMD PROCESSORS

COOLERS, FANS, AND HEAT SINKS: Because a processor generates so much heat, computer systems use a cooling assembly to keep temperatures below the Intel maximum limit of 185 degrees Fahrenheit/85 degrees Celsius. Good processor coolers maintain a temperature of 90–110 degrees F (32–43 degrees C). The cooler sits on top of the processor and consists of a fan and a heat sink, which are fins that draw heat away from the processor. The fan can then blow the heat away.

The most popular method of cooling overclocked processors is a liquid cooling system. A small pump sits inside the computer case, and tubes move water or other liquid around components and then away from them to a place where fans can cool the liquid.

INSTALL A PROCESSOR Now let’s look at the details of installing a processor in an Intel LGA1366, LGA775, 478, and AMD AM2+ socket.

Release the lever from the socket:

Orient the processor over the soc

ket so that the notches on each side of the processor match the posts on each side of the socket :

SUMMARY:


The most important component on the motherboard is the processor, or Central Processing Unit. The two major manufacturers of processors are Intel and AMD.




Processors are rated by the speed of the system bus the processor can support, the processor’s core speed, the socket and chipset the processor can use, multi-core rating, how much internal memory cache the processor has, and the computing technologies the processor can use.




A processor’s memory cache inside the processor housing can be an L1 cache (contained on the processor die), L2 cache (off the die), and L3 cache (farther from the core than L2 cache).




The processor multiplier is the value the system bus speed is multiplied by to get the processor speed.




Overclocking is running a system bus or processor at a faster frequency than the component is designed to support.




The core of a processor has two arithmetic logic units (ALUs). Multi-core processors have two, three, or four cores (called dual core, triple core, and quad core). Each core can process two threads at once.




A memory cache is made of static RAM chips. RAM stored on DIMMs installed on the motherboard is made of dynamic RAM. SRAM is faster than DRAM and is more expensive.




A multi-core processor can have L1, L2, and L3 caches. The L3 cache is shared by all cores.




Computing technologies a processor can use include MMX, SSE, SSE2, SSE3, SSE4, and 32-bit and 64-bit processing.




The technology that allows a processor to handle multiple threads in parallel is called Hyper-Threading by Intel and Hyper Transport by AMD.




The current families of Intel processors for desktops and laptops are the Core,the Pentium, and the Celeron families. Several different processors are within each family.




The current families of AMD processors for desktops and laptops are the Phenom, Athlon, Sempron, Turion Mobile, Athlon for Notebook, and Sempron for Notebook families. Several processors exist within each family.




Devices that are used to keep a system cool include CPU fans, case fans, coolers, heat sinks, liquid cooling systems, and dust-preventing tools.




A creamlike thermal compound is placed between the cooler and the processor to eliminate air pockets and to draw heat off the processor.




A 4-pin CPU fan header on the motherboard supports pulse width modulation (PWM) that controls fan speed in order to reduce the overall noise in a system.




Liquid cooling systems are sometimes used by hobbyists when overclocking a system.




When installing a processor, install the motherboard in the case first and then install the processor and cooler assembly.




The symptom of the system becoming unstable, hanging, or freezing at odd times can have multiple causes, including a failing power supply, RAM, hard drive, motherboard or processor, Windows errors, and overheating.




When troubleshooting, eliminate the simple and less expensive fixes first before you exchange a motherboard or processor.




An overheating problem can be solved by replacing a faulty fan, adding a new fan,solving problems that obstruct airflow, replacing old thermal compound, reducing the number of components, or using a larger, better-designed case.




Don’t allow a system to run if all the fans are not working. Replace any faulty fans.

Memory Modules

Random Access Memory (RAM) temporarily holds data and instructions as the CPU processes them. RAM is divided into two categories, DRAM (Dynamic RAM) and SRAM (Static RAM). static RAM (SRAM) is used for a memory cache and is contained within the processor housing. Static RAM is called that because it holds its data as long as the RAM has power. Dynamic RAM loses its data rapidly, and the memory controller must refresh it several thousand times a second. However, when the power is turned off, both SRAM and DRAM lose all their data, and are therefore called volatile memory. The entire RAM discussed in this chapter is dynamic RAM. DRAM is stored on memory modules, which are installed in memory slots on the motherboard.

New motherboards sold today uses a memory module called a DIMM (Dual Inline Memory Module) & category is DDR3 . Laptops use a smaller version of a DIMM called a SO-DIMM (small outline DIMM and pronounced “sewdim”). Micro-DIMMs are used on subnotebook computers and are smaller than SO-DIMMs. Older types are a RIMM, which is designed by Ram bus, Inc., and a SIMM (single inline memory module). The major differences among these modules are the width of the data path that each type of module accommodates and the way data moves from the system bus to the module. JEDEC (www.jedec.org) is the organization responsible for standards used by solid state devices, including RAM technologies. The goal of each new RAM technology approved by JEDEC is to increase speed and performance. When a new technology is introduced, it can take months or years before motherboard and memory manufacturers produce the related product. Also, even though an older RAM technology is no longer used by new motherboards, RAM manufacturers continue to produce the older RAM because older motherboards require these replacement modules.

Timeline of memory technologies:

DIMM TECHNOLOGIES: DIMMs use a 64-bit data path. A DIMM (Dual Inline Memory Module) gets its name because it has independent pins on opposite sides of the module. Older SIMMs have pins on both sides of the module, too, but each pin pair is tied together into a single contact. SIMMs and the early DIMMs did not run in sync with the system clock because they were too slow to keep up. Their speeds are measured in nanoseconds (ns), which is how long it takes for the module to read or write data. The first DIMM to run synchronized with the system clock was synchronous DRAM (SDRAM) which has two notches, and uses 168 pins.

Double Data Rate SDRAM (DDR SDRAM, or SDRAM II, or simply DDR): It is an improved version of SDRAM. DDR runs twice as fast as regular SDRAM, has one notch, and uses 184 pins. Instead of processing data for each beat of the system clock, as regular SDRAM does, it processes data when the beat rises and again when it falls, doubling the data rate of memory. If a motherboard runs at 200 MHz, DDR memory runs at 400 MHz. Two other improvements over DDR are DDR2 and DDR3. DDR2 is faster and uses less power than DDR. DDR3 is faster and uses less power than DDR2. Both DDR2 and DDR3 use 240 pins, But their notches are not in the same position. They are not compatible, and the different notch positions keep someone from installing a DDR2 or DDR3 DIMM in the wrong memory slot. A DIMM can have memory chips installed on one side of the module (Single-sided) or both sides of the module (Double-sided).

SINGLE, DUAL, AND TRIPLE CHANNELS: Channel means that how many DIMM slots the memory controller can address at a time. Early DIMMs only used a single channel, which means the memory controller can only access one DIMM at a time. To improve overall memory performance, dual channels allow the memory controller to communicate with two DIMMs at the same time, effectively doubling the speed of memory access. A motherboard that supports triple channels can access three DIMMs at the same time. DDR, DDR2, and DDR3 DIMMs can use dual channels. DDR3 DIMMs can also use triple channels. For dual channels or triple channels to work, the motherboard and the DIMM must support the technology. When setting up dual channeling, know that the pair of DIMMs in a channel must be equally matched in size, speed, and features, and it is recommended they come from the same manufacturer.

DIMM SPEEDS: DIMM speeds are measured either in MHz (such as 800 MHz) or PC rating (such as PC6400). A PC rating is a measure of the total bandwidth of data moving between the module and the CPU. If a DDR DIMM module that runs at 800 MHz, the module has a 64-bit (8-byte) data path, the transfer rate is 8 bytes multiplied by 800 MHz, which yields 6400 MB/second. This value equates to the PC rating of PC6400 for a DDR DIMM. A DDR2 PC rating is usually labeled PC2, and a DDR3 PC rating is labeled PC3. Some current PC ratings for DDR3 memory are PC3-16000 (2000 MHz), PC3-14400 (1800 MHz), PC3-12800 (1600 MHz), and PC3-10600 (1333 MHz). A couple of current PC ratings for DDR2 memory are PC2-6400 (800 MHz) and PC2-5400 (667 MHz). DDR memory might be rated at PC6400 (800 MHz), PC3200 (400 MHz), or PC2700 (333 MHz). An older 168-pin SDRAM DIMM might run at PC100 or PC133.

ERROR CHECKING AND PARITY: DIMMs intended to be used in servers must be extremely reliable and use an error-checking technology called ECC (error-correcting code). Some SDRAM, DDR, DDR2, and DDR3 memory modules support ECC. A DIMM normally has an even number of chips on the module, but a DIMM that supports ECC has an odd number of chips on the module. The odd chip is the ECC chip. ECC compares bits written to the module to what is later read from the module, and it can detect and correct an error in a single bit of the byte. The data path width for DIMMs is normally 64 bits, but with ECC, the data path is 72 bits. The extra 8 bits are used for error checking. Older SIMMs used an errorchecking technology called parity.

SIZE AND DENSITY OF A DIMM: DIMMs can hold from 8 MB to 4 GB of RAM. The amount of RAM installed on one DIMM is called the DIMM size or the DIMM capacity. The 64 indicates the DIMM is non-ECC, and the 72 for other DIMMs indicates ECC memory.

Label showing size (256 MB), speed (400 MHz or 3200 PC rating), and CAS Latency (CL3):

BUFFERED AND REGISTERED DIMMS: Buffers and registers hold data and amplify a signal just before the data is written to the module. Some DIMMs use buffers, some use registers, and some use neither. If a DIMM uses buffers, it’s called a buffered DIMM. If it uses registers, it’s called a registered DIMM. A fully buffered DIMM (FB-DIMM) uses an advanced buffering technique that makes it possible for servers to support a large number of DIMMs. Notches on SDRAM DIMMs are positioned to identify the technologies that the module supports. The position of the notch on the left identifies the module as registered (RFU), buffered, or un buffered memory. The notch on the right identifies the voltage used by the module. The position of each notch not only helps identify the type of module, but also prevents the wrong kind of module from being used on a motherboard.

CAS LATENCY AND RAS LATENCY: Two other memory features are CAS Latency (CAS stands for “column access strobe”) and RAS Latency (RAS stands for “row access strobe”), which are two ways of measuring access timing. Both features refer to the number of clock cycles it takes to write or read a column or row of data off a memory module. CAS Latency is used more than RAS Latency. Lower values are better than higher ones.

RIMM TECHNOLOGIES: Direct Rambus DRAM (sometimes called RDRAM or Direct RDRAM or simply Rambus) is named after Rambus, Inc., the company that developed it. A Rambus memory module is called a RIMM. RIMMs are expensive and are now slower than current DIMMs. No new motherboards are built to use RIMMs. RIMMs that use a 16-bit data bus have two notches and 184 pins & a 32-bit data bus have a single notch and 232 pins. With RIMMs, each memory slot on the motherboard must be filled to maintain continuity throughout all slots. If a slot does not hold a RIMM, it must hold a placeholder module called a C-RIMM (Continuity RIMM) to ensure continuity throughout all slots. The C-RIMM contains no memory chips.

SIMM TECHNOLOGIES: SIMMs are rated by speed, measured in nanoseconds (ns). Common SIMM speeds are 60, 70, or 80 ns. This speed is a measure of access time, which is the time it takes for the processor to access the data stored on a SIMM. Two major categories of SIMMs are 72-pin SIMMs and 30-pin SIMMs. The 72-pin SIMMs use a data path of 32 bits. Because processors expect to address 64 bits of memory at a time (one memory bank), 72-pin SIMMs are installed in matching pairs. 30-pin SIMMs use a 16-bit address bus, and, therefore, must be installed in four matching modules per bank to accommodate a 64-bit address bus to the processor.

PC Memory Types and Performance Levels

JEDEC Standard SDRAM Module (168-Pin DIMM) Speeds and Transfer Rates

JEDEC Standard DDR Module (184-Pin DIMM) Speeds and Transfer Rates

JEDEC Standard DDR2 Module (240-Pin DIMM) Speeds and Transfer Rates

JEDEC Standard DDR3 Module (240-Pin DIMM) Speeds and Transfer Rates

4GB DDR3 SO-DIMM

SUMMARY:


DRAM is stored on three kinds of modules: DIMM, SO-DIMM, RIMM, and SIMM modules.




Types of DIMMs are DDR3 and DDR2 DIMMs that have 240 pins, DDR DIMMs with 184 pins, and SDRAM DIMMs with 168 pins. A RIMM has 184 pins, and SIMMs can have 72 or 30 pins. SIMMs and RIMMs are outdated technologies.




DIMMs can work together in dual channels or triple channels so that the memory controller can access more than one DIMM at a time to improve performance. In a channel, all DIMMs must match in size, speed, and features. DDR3 DIMMs can use dual or triple channeling, but DDR and DDR2 DIMMs can only use dual channels.




DIMM and RIMM speeds are measured in MHz (for example, 1333 MHz) or PC rating (for example, PC3-10600). SIMM speeds are measured in ns (for example, 80 ns).




The memory controller can check memory for errors and possibly correct those errors using ECC (error-correcting code). Using parity, an older technology, the controller could only recognize an error had occurred, but not correct it.




Buffers and registers are used to hold data and amplify a data signal. A fully buffered DIMM (FBDIMM) uses advanced buffering to make it possible for servers to support a large number of DIMMs.




CAS Latency (CL) and RAS Latency (RL) measure access time to memory. The lower values are faster than the higher values.




RIMMs require that every RIMM slot be populated. If a RIMM is not installed in the slot, install a placeholder module called a C-RIMM.




SIMMs are installed in banks of four or two modules.




When upgrading memory, use the type, size, and speed the motherboard supports and match new modules to those already installed. Features to match include buffered, registered, unbuffered, single-sided, double-sided, CL rating, tin or gold connectors, support for dual or triple channeling, ECC, non-ECC, parity, nonparity, speed in ns, MHz, or PC rating, DDR, DDR2, DDR3, and size in MB or GB. Using memory made by the same manufacturer is recommended

Hard Disk Drive

A hard disk drive (HDD), most often called a hard drive, comes in two sizes for personal computers: the 2.5" size is used for laptop computers and the 3.5" size is used for desktops. In addition, a smaller 1.8" size hard drive is used in some low-end laptops and other equipment such as MP3 players.

SOLID STATE, MAGNETIC, AND HYBRID DRIVES: Inside the drive housing, two types of technologies can be used: solid state and magnetic. A solid state drive (SSD) has no moving parts. The drives are built using nonvolatile flash memory, which is similar to that used for USB flash drives.

A magnetic hard drive has one, two, or more platters, or disks, that stack together and spin inside a sealed metal housing. Outside a Circuit Board contains firmware to control reading and writing data to the drive and to communicate with the motherboard. The top and bottom of each disk have a read/write head that moves across the disk surface as all the disks rotate on a spindle. All the read/write heads are controlled by an actuator, which moves the read/write heads across the disk surfaces in unison. The disk surfaces are covered with a magnetic medium that can hold data as magnetized spots.

You can see in below close-up that this drive has two platters. Both sides of each platter are used to store data. So the drive has four heads because there are two platters, each having two heads.

Some hard drives are hybrid hard drives, using both technologies. For example, the 2.5” Seagate Momentus hybrid hard drive holds 80 GB of data and has a 256 MB flash component. Often-used data is stored on the faster flash component. Also, when data is first written to the faster flash component and later moved to the slower magnetic component. For a hybrid drive to function, the operating system must support it.

HOW DATA IS ORGANIZED ON A HARD DRIVE: Each disk surface on a hard drive is divided into concentric circles, called tracks. Each track is further divided into 512-byte segments called sectors. All the tracks that are the same distance from the center of the platters make up one cylinder. Track and sector markings are written to a hard drive before it leaves the factory in a process called low-level formatting. The total number of sectors on the drive determines the drive capacity. Today’s drive capacities are usually measured in GB (gigabytes) or TB (terabytes, each of which is 1,024 gigabytes).

Firmware on a circuit board inside the drive housing is responsible for writing and reading data to these tracks and sectors and for keeping track of where everything is stored on the drive. BIOS and the OS use a simple sequential numbering system called logical block addressing (LBA) to address all the sectors on the hard drive without regard to where these sectors are located.

When a hard drive is first installed in a system, Windows initializes the drive and identifies it as a basic disk. A basic disk is a single hard drive that works independently of other hard drives. The initializing process writes a Master Boot Record (MBR) to the drive. MBR is the first sector at the beginning of a hard drive (512 bytes). It contains two items: 1. The master boot program (446 bytes), which loads the OS boot program stored in the OS boot record. This OS boot program begins the process of loading OS. 2. The partition table, which contains the description, location, and size of each partition on the drive. For Windowsbased systems, the MBR has space for four 16-byte entries that are used to define up to four partitions on the drive. For each partition, the 16 bytes are used to hold the beginning and ending location of the partition, the number of sectors in the partition, and whether the partition is bootable or not. The one bootable partition is called the active partition. The active partition is always a primary partition. The next step is to create a partition on the drive in a process called high-level formatting or operating system formatting. During this process, you specify the size of the partition and what file system it will use. A partition can be a primary partition or an extended partition. A primary partition is also called a volume. The volume is assigned a drive letter (such as drive C: ) and is formatted using a file system. A file system is the overall structure an OS uses to name, store, and organize files on a drive. In a file system, a cluster is the smallest unit of space on a disk for storing a file and is made up of one or more sectors. A file system tracks how these clusters are used for each file stored on the disk. One of the four partitions on a drive can be an extended partition. An extended partition can be divided into one or more logical drives. Each logical drive is assigned a drive letter and is formatted using its own file system.

HARD DRIVE INTERFACE STANDARDS: Hard drives have different ways to interface with the computer. The three current methods used by internal hard drives are Parallel ATA (PATA), Serial ATA(SATA), and SCSI. External hard drives can connect to a computer by way of external SATA (eSATA), SCSI, FireWire, USB, Fire-Wire or a variation of SCSI called Fibre Channel. Currently, the most popular solutions for external hard drives are USB and FireWire.

THE ATA INTERFACE STANDARDS: The ATA (Advanced Technology Attachment) interface standards define how hard drives and other drives such as CD, DVD, tape, and Blu-ray drives interface with a computer system. The standards define data speeds and transfer methods between the drive controller, the BIOS, the chipset on the motherboard, and the OS. The standards also define the type of cables and connectors used by the drive. The ATA interface standards are developed by Technical Committee T13 (www.t13.org) and published by ANSI (American National Standards Institute, www.ansi.org) The ATA standards can be categorized into two groups: PATA and SATA.

S.M.A.R.T. (Self-Monitoring Analysis and Reporting Technology) is a system BIOS feature that monitors hard drive performance, disk spin up time, temperature, distance between the head and the disk, and other mechanical activities of the drive in order to predict when the drive is likely to fail. If S.M.A.R.T. suspects a drive failure is about to happen, it displays a warning message. S.M.A.R.T. can be enabled and disabled in BIOS setup.

PARALLEL ATA OR EIDE DRIVE STANDARDS: Parallel ATA, also called the EIDE (Enhanced IDE) or IDE (Integrated Drive Electronics) standard, allows for one or two IDE connectors on a motherboard, each using a 40 Wire or 80 Wire data cable. These ribbon cables can accommodate one or two drives. All PATA standards since ATA-2 support this configuration. Using this standard, up to four parallel ATA devices can connect to a motherboard using two data cables. Parallel ATA or EIDE applies to other drives besides hard drives, including CD drives, DVD drives, Tape drives, ZIP Drives etc. An EIDE drive such as a CD or DVD drive must follow the ATAPI (Advanced Technology Attachment Packet Interface) standard in order to connect to a system using an IDE connector.

Two Types of PATA Ribbon Cables: Under parallel ATA, two types of ribbon cables are used. The older cable has 40 pins and 40 wires. The 80conductor IDE cable has 40 pins and 80 wires. Forty wires are used for communication and data, and an additional 40 ground wires reduce crosstalk on the cable. For maximum performance, an 80-conductor IDE cable is required by ATA/66 and above.

DMA or PIO Transfer Modes: A hard drive uses one of two methods to transfer data between the hard drive and memory: DMA (Direct Memory Access) transfer mode or PIO (Programmed Input/Output) transfer mode. DMA transfers data directly from the drive to memory without involving the CPU. PIO mode involves the CPU and is slower than DMA mode. There are five PIO modes used by hard drives, from the slowest (PIO mode 0) to the fastest (PIO mode 4), and seven DMA modes from the slowest (DMA mode 0) to the fastest (DMA mode 6). All motherboards today support Ultra DMA, which means that data is transferred twice for each clock beat, at the beginning and again at the end.

Independent Device Timing: There are different hard drive standards, each running at different speeds. If two hard drives share the same parallel ATA cable but use different standards, both drives will run at the speed of the slower drive unless the motherboard chipset controlling the ATA connections supports a feature called Independent Device Timing. Most chipsets today support this feature and with it, the two drives can run at different speeds.

SERIAL ATA STANDARDS: SATA uses a serial data path rather than the traditional parallel data path. Essentially, the difference between the two is that data is placed on a serial cable one bit following the next, but with parallel cabling, all data in a byte is placed on the cable at one time. Serial ATA interfaces are much faster than PATA interfaces and are used by all types of drives, including hard drives, CD, DVD, Blu-ray, and tape drives. A motherboard can have two, four, six, or more SATA connectors, which are much easier to configure and use than PATA connectors. SATA supports hot-swapping, also called hot-plugging. With hot-swapping, you can connect and disconnect a drive while the system is running. In addition to internal SATA connectors, the motherboard or an expansion card can provide external SATA (eSATA) ports for external drives. External SATA (eSATA) is up to six times faster than USB or FireWire. External SATA drives use a special external shielded serial ATA cable up to 2 meters long.

Two eSATA ports on a motherboard

SCSI TECHNOLOGY: Other than ATA, another interface standard for drives and other devices is SCSI, which is primarily used in servers. SCSI standards can be used by many internal and external devices, including hard drives, CD-ROM drives, DVD drives, printers, and scanners. SCSI (pronounced “scuzzy”) stands for Small Computer System Interface, and is a standard for communication between a subsystem of peripheral devices and the system bus. The SCSI bus can support up to 7 or 15 devices, depending on the SCSI standard. If a motherboard does not have an embedded SCSI controller, the gateway from the SCSI bus to the system bus is the SCSI host adapter card.

The three major versions of SCSI are SCSI-1, SCSI-2, and SCSI-3, commonly known as Regular SCSI, Fast SCSI, and Ultra SCSI. The latest SCSI standard, serial SCSI, also called serial attached SCSI (SAS).

FIBRE CHANNEL: Fiabre Channel is a type of SCSI technology, for high-end server solutions. Using Fibre Channel, you can connect up to 126 devices together on a single Fibre Channel bus. Fibre Channel is faster than other SCSI implementations, when more than five hard drives are strung together to provide massive secondary storage. Fabre Channel is too expensive.

RAID: HARD DRIVES WORKING TOGETHER: A technology that configures two or more hard drives to work together as an array of drives is called RAID (Redundant Array of Independent Disks). The three most commonly used RAID Levels are RAID 0, RAID 1, and RAID 5.

RAID 0 uses space from two or more physical disks to increase the disk space available for a single volume. RAID 0 writes to the physical disks evenly across all Disks to improves performance. Windows calls RAID 0 a striped volume. To understand that term, think of data striped—or written across—several hard drives.

RAID 1 is a type of drive imaging. It duplicates data on one drive to another drive and is used for fault tolerance. (A drive image is a duplication of everything written to a hard drive.) Each drive has its own volume, and the two volumes are called mirrors. If one drive fails, the other continues to operate and data is not lost. Windows calls RAID 1 a mirrored volume.

RAID 5 stripes data across three or more drives and uses parity checking, so that if one drive fails, the other drives can re-create the data stored on the failed drive. Data is not duplicated, and, therefore, RAID 5 makes better use of volume capacity. RAID 5 drives increase performance and provide fault tolerance. Windows calls these drives RAID5 volumes. FLOPPY DRIVE: Even though a floppy disk drive (FDD) holds only 1.44 MB of data, these drives are still used in some computers today. Floppy drives can be especially useful when recovering from a failed BIOS update.

FLOPPY DRIVE FILE SYSTEM: When floppy disks are first manufactured they are blank sheets of magnetically coated plastic. During the formatting process, tracks and sectors to hold the data are written to the blank surface. There are 80 tracks each side of the disk. The tracks are numbered 0 through 79. Each track has 18 sectors, numbered 1 through 18 for a total of 1440 sectors on each side. Because each sector holds 512 bytes of data, a 31⁄2", high-density floppy disk has 2880 x 512 = 1,474,560 bytes of data. Divide this number by 1024 to convert bytes to kilobytes and you will find out that the storage capacity of this disk is 1440 kilobytes.

STEPS TO INSTALL HARD DISK DRIVE :

If you have a PATA drive and a SATA connector on the motherboard, or you have a SATA drive and a PATA connector on the motherboard, you can purchase an adapter to make the hard drive connector fit your motherboard connector.

You can also install a SATA and/or PATA controller card that can provide internal PATA or SATA connectors and external eSATA connectors, when the motherboard drive connectors are not functioning; or the motherboard does not support an ATA standard you want to implement (such as a SATA II drive).

STEPS TO INSTALL SATA HARD DISK DRIVE: 1.

Select a bay, slide the drive in the bay, and secure both sides of the drive with two short screws.

2. Connect SATA Cable to the SATA connectors labeled SATA1 and SATA2 on the board before you use the SATA3 and SATA4. 3. Connect a SATA or 4-pin power connector from the power supply to the drive. 4. To verify the drive installation, enter BIOS setup and look for the drive.

STEPS TO INSTALL A PARALLEL ATA DRIVE: Old motherboard offers two IDE connectors Primary & Secondary. Each connector accommodates one IDE channel, and each channel can accommodate one or two IDE devices.


Primary IDE channel master




Primary IDE channel slave




Secondary IDE channel master




Secondary IDE channel slave

The master or slave designations are made by setting jumpers or DIP switches on the devices, or by using a special cable-select data cable. The connectors on a parallel ATA 80-conductor cable are color-coded. Use the blue end to connect to the motherboard; If you only have one drive connected to the cable use the black end to connect to the drive. not the gray connector in the middle.

The primary IDE channel connector is often color-coded as blue:

SUMMARY:


A hard disk drive (HDD) comes in two sizes: 3.5" for desktop computers, and 2.5" for laptops.




A hard drive can be a magnetic drive, a solid state drive, or a hybrid drive. A solid state drive is more expensive, faster, more reliable, and uses less power than a magnetic drive.




A hard drive is low-level formatted at the factory where track and sector markings are written to the drive. Drive capacity is measured in GB or TB.




When Windows prepares a drive as a basic disk, it installs a Master Boot Record (MBR) which contains a partition table and a master boot program.




A primary partition is also called a volume, simple volume, or basic volume. An extended partition can have more than one logical drive.




Two file systems used for hard drives are FAT32 (the older system) and NTFS (the newer system).




Most hard drives use the ATA interface standards. The two main categories of ATA are parallel ATA and serial ATA. Serial ATA is easier to configure and better performing than PATA. External SATA ports are called eSATA ports.




S.M.A.R.T. is a self-monitoring technology whereby the BIOS monitors the health of the hard drive and warns of an impending failure.




ATAPI standards are used by optical drives and other drives that use the ATA interface on a motherboard or controller card.




Several PATA standards are Fast ATA, Ultra ATA, Ultra ATA/66, Ultra ATA/100, and Ultra ATA/133.




Three SATA standards provide data transfer rates of 1.5 Gb/sec, 3.0 Gb/sec, and 6.0 Gb/sec. Currently, the second standard is the most popular and is sometimes called SATA-300.




SCSI is an interface standard for high-end hard drives used in servers.




RAID technology uses an array of hard drives used to provide fault tolerance and/or improvement in performance.




When selecting a hard drive, consider the capacity of the drive, the spindle speed (for magnetic drives), the interface standard used, the cache or buffer size, and the average seek time.




SATA drives require no configuration and are installed using a power cord and a single SATA data cable.




PATA drives require you to set a jumper to determine if the drive will be the master or slave on a single cable. The PATA cable can accommodate two drives. A PATA motherboard has two PATA connectors for a total of four PATA drives in the system.




Hardware RAID can be implemented by the motherboard or a RAID controller card. Software RAID is implemented by Vista or Windows XP. Best practice is to use hardware RAID rather than software RAID.

Multi Media & Storage

SOUND CARDS AND ONBOARD SOUND: A sound card (an expansion card with sound ports) or onboard sound (sound ports embedded on a motherboard) can record sound, save it in a file on your hard drive, and play it back.

Sound Blaster X-Fi Titanium card uses a PCIe x1 slot and supports up to eight surround sound 7.1 speakers:

TV TUNER AND VIDEO CAPTURE CARDS: A TV tuner card can turn computer into a television. A port on the card receives input from a TV cable and lets you view television on your computer monitor. A video capture card lets you capture video input and save it to a file on your hard drive.

Laptop with embedded TV tuner and video capture abilities

TV tuner card features:


Ability to do instant replay and program scheduling.




Input ports for coaxial cable TV, TV antenna, video equipment, and game boxes.




Ability to handle analog and digital (including HDTV) input signals.




Remote control.

OPTICAL STORAGE: CDs and DVDs are popular storage media for multimedia data. Both DVD and CD technologies use patterns of tiny lands and pits on the surface of a disc to represent bits, which a laser beam can then read. CD (compact disc) drives use the CDFS (Compact Disc File System) or the UDF (Universal Disk Format) file system, while DVD (digital versatile disc) drives use the newer UDF file system. The latest optical storage technology is Blu-Ray Disc (BD) uses the UDF version 2.5 file system. Data is written to optical discs by using a laser beam to burn or etch pits into the surface of the disc. Lands

are smooth and level areas, and pits are recessed areas; each represents either a 1 or a 0, respectively. The bits are read by the drive with a laser beam that distinguishes between a pit and a land by the amount of deflection or scattering that occurs when the light beam hits the surface.

DVD or Blu-Ray Disc can hold data in two layers. Some Discs contains data layers on both sides of the Disc. These discs can hold a total of four layers on one disc.

CDs and DVDs both use red laser beams, but the wavelength of the DVD laser beam is shorter than that of the CD laser beam. The shorter wavelength allows the beam to be more accurate. So that more data can be stored on a DVD than on a CD. Blu-ray uses a blue laser beam, which has shorter wavelength than red beam, allows Blu-Ray technology to store more data than a DVD.

Data Storage

Capacities:


CD can hold 700 MB




Single-sided, single-layer DVD can hold 4.7 GB




Single-sided, dual-layer DVD can hold 8.5 GB




Double-sided, single-layer DVD can hold 9.4 GB




Double-sided, dual-layer DVD can hold 17 GB




Single-layer BD can hold 25 GB




Dual-layer BD can hold 50 GB Data on an optical disc is laid out as one continuous spiral of sectors of equal length that hold equal amounts of data. For a CD, if laid out in a straight line, this spiral would be 3.5 miles long. In order to read each sector on the spiral at a constant linear velocity (CLV), the disc spins faster when the read-write head is near the center of the disc.

STANDARDS SUPPORTED BY CD, DVD, AND BD DRIVES:

CARING FOR OPTICAL DRIVES AND DISCS: Most problems with CD, DVD, and BD discs are caused by dust, fingerprints, scratches, surface defects. Use these precautions when handling CD, DVD, or BD:


Hold the disc by the edge; do not touch the side of the disc where data is stored.




To remove dust or fingerprints, use a clean, soft, dry cloth. Don’t wipe the disc in a circular motion. Always wipe from the center of the disc out toward the edge.




Don’t paste paper on the surface of a disc. Don’t paste any labels on the top of the disc, because this can imbalance the disc and cause the drive to vibrate.




Don’t subject a disc to heat or leave it in direct sunlight.




Don’t bend a disc.




Don’t drop a disc or subject it to shock.




If a disc gets stuck in the drive, use the emergency eject hole to remove it.




When closing a CD, DVD, or BD tray, don’t push on the tray. Press the close button




on the front of the drive.




To fix a scratch on a disc, use the repair solution made of Aluminum Oxide. Apply a small amount to the scratch and gently rub it with soft cloth. Then clean the disc using the cleaning solution.

SOLID-STATE STORAGE: A storage device that uses memory chips is called a solid-state device (SSD), also called a solid-state drive. Examples of solid-state devices are USB flash drives, flash memory cards, and solid-state hard drives.

Flash Memory Cards: Several types of flash memory cards are used in digital cameras, cell phones, MP3 players, handheld computers, digital camcorders, and other portable devices.

MicroSDHC card with four adapters :

EXTERNAL HARD DRIVES: External hard drives are a great method of keeping backups of data stored on your hard drive. External hard drives can be magnetic or solid-state drives. External hard drives use USB 3.0, USB 2.0, FireWire, eSATA, or SCSI ports to connect to a computer.

TAPE DRIVES: Tape drives are less expensive for backups of an entire hard drive or portions of it. Tapes currently have capacities of 20 GB to 1.3 TB compressed and come in several types and formats. The biggest disadvantage of using tape drives is that data is stored on tape by sequential access; to read data from anywhere on the tape, you must start at the beginning of the tape and read until you come to the sought-after data. Sequential access makes recovering files slow, so tapes are not used for general-purpose data storage.

List of some of the more common types of tape cartridges: 1. DDS-1, DDS-2, DDS-3, and DDS-4 are popular types. DDS-4 holds up to 20 GB native or 40 GB compressed data. 2. DAT72 (also called DDS-5) holds up to 36 GB native or 72 GB compressed data. 3. LTO cartridges (LTO Ultrium 2, LTO Ultrium 3, and LTO Ultrium 4). LTO Ultrium 4 holds up to 800 GB native or 1.6 TB compressed data. 4. DLT IV or DLT-4 holds up to 40 GB native or 80 GB compressed data. 5. Super DLTtape II holds up to 300 GB native or 600 GB compressed data.

This Maxell LTO Ultrium 3 data tape cartridge can hold up to 800 GB of compressed data :


Multimedia PCs and devices are designed to create and reproduce lifelike presentations of sight and sound.
A TV tuner card turns your PC or notebook into a television. A video capture card allows you to capture input from a camcorder or directly from TV. Combo cards have both
bilities.
CDs, DVDs, and BDs are optical devices with data physically embedded into the surface of the disc. Laser beams are used to read data off the disc by measuring light reflection.
CDs use the CDFS or UDF file systems. DVDs use the UDF file system, and BDs use the UDF version 2.5 file system.
Optical discs can be recordable (such as a CD-R disc) or rewriteable (such as a DVD-RW disc).
Optical discs can use laser-burned labels using LightScribe or Labelflash, or labels can be printed on the top surface of a disc using an ink-jet printer with this capability.
Solid-state storage devices include USB flash drives, flash memory cards, and solid-state hard drives.
Current types of flash memory cards include SDHC, MicroSDHC, MiniSDHC, SD,MiniSD, Memory Stick PRO Duo, Memory Stick Micro M2, MicroSD, CompactFlash I and II, and UDMA

compactFlash. Older types of flash memory cards include MMC,RS-MMC, Microdrive CF, Memory Stick, xD-Picture Card, and SmartMedia.
External hard drives can use a USB, FireWire, eSATA, or SCSI port.
Tape drives are an inexpensive way to back up an entire hard drive or portions of it. Tape drives are more convenient for backups than removable disks. The disadvantage of tape drives is that data can only be accessed sequentially.

Power Supply

AC AND DC: Electricity can be either AC, alternating current, or DC, direct current. Alternating current (AC) goes back and forth, or oscillates, rather than traveling in only one direction. AC is the most economical way to transmit electricity. By decreasing current and increasing voltage, we can force alternating current to travel long distances. When alternating current reaches its destination, it is made more suitable for driving our electrical devices by decreasing voltage. Direct current (DC) travels in only one direction and is the type of current that most electronic devices require, including computers. A rectifier is a device that converts AC to DC, and an inverter is a device that converts DC to AC. A transformer is a device that changes the ratio of voltage to current. The transformer does not change the amount of power.

Instead of throwing away extra input energy like linear power supply , a switching power supply creates a feedback loop. Feedback senses the output voltage, then switches the primary DC voltage duty cycle as needed to maintain steady levels at the output. AC line voltage entering the supply is immediately converted to pulsating DC, then filtered to provide a primary DC voltage. Notice that unlike a linear supply, AC is not transformed before rectification. On start-up, the switching transistor is turned on and off at a high frequency (usually 20kHz to 40kHz), and a long duty cycle (the amount of time that a signal is “on,” compared to its overall cycle) creates a pulsating DC used as the primary signal for a step-down transformer. The duty cycle of pulsating DC will affect the AC voltage level generated on the transformer’s secondary. Secondary voltage is re-rectified and re-filtered to form a secondary dc voltage that is actually applied to the load. The duty cycle is continuously adjusted by the sensing/switching circuit. Switching power supplies can reach efficiencies higher than 85%. More efficiency means less heat is generated by the supply, so components can be smaller and packaged more tightly.

Block diagram of a switching power supply

Simplified diagram of a switching power supply

Form Factor: When we assemble a new system, or replace components in an existing system, the motherboard, power supply, and case must all be compatible. The standards that describe the size, shape, and major features of these components so that they work together are called form factors. According to the form factor of the motherboard, you must select the same form factor for the case and power supply. Using a matching form factor for the motherboard, power supply, and case assures you that:


The motherboard fits in the case.




The power supply cords to the motherboard provide the correct voltage, and the connectors match the connections on the board.




The holes in the motherboard align with the holes in the case to fix the board to the case.




Holes in the case align with ports coming off the motherboard.




For some form factors, wires for switches and lights on the front of the case match up with connections on the motherboard.




The holes in the power supply align with holes in the case to fix the power supply to the case.




TYPES OF FORM FACTORS

TYPES OF FORM FACTORS

ATX FORM FACTOR: ATX (Advanced Technology Extended) is the most commonly used form factor today. It is an open, nonproprietary industry specification originally developed by Intel in 1995, and has undergone several revisions since then. The first ATX power supplies and motherboards used a single power connector called the P1 connector that had 20 pins. These pins provided +3.3 volts, +5 volts, +12 volts, -12 volts, and an optional and rarely used -5 volts.

When processors began to require more power, the ATX Version 2.1 specifications added a 4-pin auxiliary connector near the processor socket to provide an additional 12 V of power. A power supply that provides this 4-pin 12-volt power cord is called an ATX12V power supply.

Later, when PCI Express slots were added to motherboards, more power was required and a new ATX specification (ATX Version 2.2) allowed for a 24-pin P1 connector, which is backward compatible with the 20-pin P1 connector. The extra 4 pins on the connector provide +12 volts, +5 volts, and +3.3 volts pins.

A 20-pin power cord plugged into a 24-pin P1 connector on an ATX motherboard:

Pin out of the 24-pin power connector:

Another feature of an ATX motherboard is a soft switch, sometimes called the soft power feature that can turn off the power to a system after the shutdown procedure is done. In addition, BIOS setup can be configured to cause a keystroke or network activity to power up the system (wake on LAN). When a user presses the power switch on the front of the case while the computer is on, the OS goes through a normal shutdown procedure before powering off.

HOW TO SELECT A POWER SUPPLY: When selecting a power supply, match the form factor to that used by the case and motherboard, make sure it provides the connectors you need, and match the wattage capacity to the requirements of the system. Use a power supply that is rated about 30 percent higher than you expect the system will use. Power supplies that run at less than peak performance last longer and don’t overheat. To know what size power supply you need, add up the wattage requirements of all components, and add 30 percent.

TYPES OF COMPUTER CASES: Several types and sizes of cases are on the market for each form factor. The computer case, sometimes called the chassis, houses the power supply, motherboard, expansion cards, and drives. The case has lights and switches on the front panel that can be used to control and monitor the PC.

SURGE PROTECTION AND BATTERY BACKUP: The power supplies in most computers can operate over a wide range of electrical voltage inputs; however, operating the computer under these conditions for extended periods of time can shorten the power supply’s life and also the computer’s. Also, electrical storms can end a computer’s life quite suddenly. To prevent such things, consider installing following devices to filter AC input.


Power strips that provide additional outlets without providing any protection from changes in AC power




Surge protectors which protect equipment against power spikes or surges




Voltage Stabilizers that condition or smooth out the highs and lows in Voltage




Uninterruptible Power Supplies (UPS) that provide backup power

SURGE PROTECTORS: A surge protector, also called a Spike Buster, protects equipment against sudden changes in power level, such as spikes from lightning strikes. The device typically provides one or more power outlets, an on/off switch, and a protection light.

UNINTERRUPTIBLE POWER SUPPLY: The uninterruptible power supply (UPS) provides backup power in the event that the AC fails completely. The UPS also provides some filtering of the AC and Conditions the line to account for both Voltage Fluctuations and spikes.

The Smart UPS: A Smart UPS (also called an Intelligent UPS) can be controlled by software from a computer. To accommodate this feature, a UPS has a USB connection to the PC and a microprocessor on board. Some activities this utility software and a smart UPS can do as following:


Diagnose the UPS & Battery and schedule tests.




Monitor the quality of electricity receiving and load carrying the UPS.




Send an alarm to workstations on a network to prepare for a shutdown.




Shutdown all servers protected by the UPS during Power Failure.

SUMMARY:


A form factor is a set of specifications for the size and configuration of hardware components, such as cases, power supplies, and motherboards.




The most common form factor today is ATX and Micro ATX. Important features of a power supply to consider when purchasing it are its form factor, number and type of connector types it provides, wattage / capacity, and warranty.




To decide on the wattage capacity of a power supply, add up the wattage requirements for all components in a system and then increase that total by about 30 percent.




Devices that control the electricity to a computer include surge suppressors, Voltage Stabilizers and UPS.

Introduction To OPERATING SYSTEMS

An Operating System (OS) is software that controls a computer. It manages hardware, runs applications, provides an interface for users, and stores, retrieves, & manipulates files. Several applications might be installed on a computer to meet various user needs, but a computer really needs only one operating system.

DOS (DISK OPERATING SYSTEM): In 1986, MS-DOS (known as DOS) was introduced and became the most popular OS for computers using the Intel 8086 processors.

DOS WITH WINDOWS 3.X: Early versions of Windows 3.x used DOS as the operating system. Because Windows 3.x didn’t perform OS functions, but simply served as a user friendly intermediate program between DOS, applications, and the user. Windows 3.x offered a Graphical User Interface (GUI) and the ability to keep more than one applications open at the same time. A graphical user interface is an interface that uses graphics as compared to a command-driven interface.

WINDOWS 9X/ME: Windows 95, Windows 98, and Windows Me used some DOS programs as part of the underlying OS (called a DOS core). These were true operating systems that provided a user friendly interface. Because of the DOS core, we can use DOS startup disk to troubleshoot Windows 9x.

WINDOWS NT: Windows NT (New Technology) came in two versions: Windows NT Workstation and Windows NT Server. The workstation version was used on high-end corporate or engineering desktop computers, and the server

version was used to control a network. Windows NT corrected many problems with Windows 9x/Me because it completely rewrote the OS core, totally eliminating the DOS core. Windows NT was the first Windows OS that did all its processing using 32 bits at a time as compared to DOS, which processed 16 bits at a time and Windows 9x/Me, which used a combination of 16-bit and 32-bit processing.

WINDOWS 2000: Windows 2000 was an upgrade of Windows NT, came in several versions like Windows 2000 Professional, Windows 2000 Server, Advanced Server, and Datacenter Server. Windows 2000 offered several improvements over Windows NT, including a more stable environment, support for Plug and Play, Device Manager, Recovery Console, Active Directory, better network support.

WINDOWS XP: Windows XP is an upgrade of Windows 2000 and attempts to integrate Windows 9x/Me and 2000 and provided support for multimedia and networking technologies. The two main versions are Windows XP Home Edition and Windows XP Professional, other versions are Windows XP Media Center Edition, Windows XP Tablet PC Edition, and Windows XP Professional x64 Edition. Windows XP is the first Windows OS to allow multiple users to log on simultaneously to the OS, each with their own applications open. XP includes several new security features, including Windows Firewall. Windows XP was first released with some bugs, the second service pack (Service Pack 2) resolved most of these problems. A service pack is a major update or fix to an OS released by Microsoft. Minor updates or fixes that are released more frequently are called patches. Windows XP has undergone three service packs, making it an extremely stable OS.

WINDOWS VISTA: Windows Vista, an upgrade to Windows XP. Vista was better tested than XP before its release. But problems with Vista are lack of compatibility with older hardware and software, the large amount of computer resources that Vista requires, and its slow performance. The first problem is partly caused by hardware manufacturers not providing Vista drivers for their devices that were originally sold with XP drivers. The second problem means that many low-end desktop and laptop computers can’t run Vista.

WINDOWS 7: For this current release of Windows, Microsoft learned its mistakes with Vista and created an operating system with speed, stability and minimal system requirements. Microsoft ditched the gadget bar from Vista, replacing it with a cleaner feel. This version was released in 2009.

Windows 8: This latest Windows release is getting a lot of attention. With its redesigned Metro-style user interface and Windows Store, this version is, once again, redefining what Windows is. It also comes with integrated antivirus protection, a virtual hard disk. It promises faster boot time, touch screen compatibility and the ability to create a bootable USB flash drive. It may not be enough to get people to switch from Windows 7, but at least it's a glimpse into the future of the Windows operating system.

MAC OS: Mac OS, which has its roots in the UNIX OS, is available only on Macintosh computers from the Apple Corporation. The Mac and the Mac OS were first introduced in 1984. The latest OS is Mac OS X (ten), which has had several releases. The latest release is called Mac OS X Leopard.

In earlier days Macintosh computers were built using PowerPC processors by IBM or Motorola. Macs now use Intel processors, which make it possible for Windows to run on a Mac. Boot Camp software by Apple can be used to install Windows on a Mac computer as a dual boot with Mac OS X. (A dual boot makes it possible to boot a computer into one of two installed OSs.)

LINUX: Linux is a variation of UNIX that was created by Linus Torvalds when he was a student at the University of Helsinki in Finland. Versions of LINUX are available for free, and all the underlying programming instructions (called source code) are also freely distributed. Linux is distributed by several different companies like SuSE (www.novell.com/linux/suse), Red Hat (www.redhat.com), Turbo Linux (www.turbolinux.com), Slack ware Linux (www.slackware.com), and Ubuntu (www.ubuntu.com).

WHAT AN OPERATING SYSTEM DOES Function 1. Provide a user interface • Performing housekeeping procedures requested by the user, often concerning secondary storage devices, such as reorganizing a hard drive, deleting files, copying files, and changing the system date • Provides the user to manage desktop, hardware, applications, and data

Function 2. Manage files • Managing files on hard drives, DVD drives, CD drives, floppy drives etc. • Creating, storing, retrieving, deleting, and moving files

Function 3. Manage hardware • Managing the BIOS (programs permanently stored on hardware devices) • Managing memory, which is a temporary place to store data and instructions as they are being processed • Diagnosing problems with software and hardware • Interfacing between hardware and software.

Function 4. Manage applications • Installing and uninstalling applications • Running applications and managing the interface to the hardware.

COMPONENTS OF WINDOWS Every operating system has three main internal components: the shell, the kernel, and configuration data. Shell is the portion of an OS that relates to the user and to applications; the kernel is responsible for interacting with hardware. Configuration data is information the OS keeps about hardware, applications, data, and users.

THE WINDOWS SHELL: The shell provides a way for the user to do such things as select files to copy, Delete, Move, install an application, or change the wallpaper on the Windows desktop etc. The shell does this using various interface tools such as Windows Explorer, Control Panel, My Computer etc., by command, menu, or icon-driven interfaces for the user. For applications, the shell provides commands and procedures that applications can call on to do such things as print a spreadsheet, read from a database etc. The shell is made up of several subsystems. The Win32 security subsystem, provides logon to the system and other security functions, including privileges for file access. All applications relate to Windows by way of the Win32 subsystem.

THE WINDOWS KERNEL: The kernel, or core, of the OS is responsible for interacting with hardware. It has more power to communicate with hardware devices than Shell. The kernel has two main components. The HAL (hardware abstraction layer) is the layer closest to the hardware and the executive services interface between shell and the HAL. When Windows is first installed, it builds the HAL based on the type of CPU & Chipset installed. The HAL cannot be moved from one computer to another, which is one reason you cannot copy a Windows installation from one computer to another unless CPU & Chipset matches.

CONFIGURATION DATA: This keep hardware and software configuration information, user preferences, and application settings. This information is used when the OS is first loaded and when needed by hardware, applications, and users. Windows uses a database called the Registry for most of this information. In addition, Windows keeps some data in text files called initialization files, which often have an .ini or .inf file extension.

DOS Disk Operating System

BOOTING: MS-DOS Require these files to Boot. 1.

IO.SYS

2.

MSDOS.SYS

3.

COMMAND.COM Optional

4. CONFIG.SYS 5.

AUTOEXEC.BAT In BOOTING process the first step is Power On Self Test (POST). The Power On Self Test is a program that has been recorded on a ROM chip located on the motherboard. When the self test passed, it is time to load DOS using another program in ROM called bootstrap loader. If bootstrap loader find a disk with valid operating system, it starts the program on the boot sectors of the disk. The first file loaded is IO.SYS and the second file is MSDOS.SYS loaded into memory. It checks the disk’s boot directory (normally C:\) to see whether a file named CONFIG.SYS is present. If this file is found, it is loaded into memory. Each line of CONFIG.SYS specifies some type of configuration information, such as a device driver to be loaded or a system setting to be made. After these settings are established, COMMAND.COM is loaded. COMMAND.COM is the user interface to DOS. It runs a file called AUTOEXEC.BAT if present in the boot directory. AUTOEXEC.BAT is a standard batch file that usually contains commands to customize your DOS installation.

Internal Versus External DOS recognizes and responds to more than 80 commands. The commands contained within the DOS command interpreter, COMMAND.COM are internal commands. Other commands are stored as utility programs in a directory. Because these commands are not built into the command processor, they are called external commands. MS-DOS file name follow 8dot3 format and is divided into two parts as primary name and secondary name. Primary name is maximum 8 characters long and secondary name is up to 4 characters with dot.

Keyboard Shortcuts UP (↑) and DOWN (↓) arrows recall previously entered commands. ESC clears the present command line. F7 key displays command history and ALT+F7/ESC hides it. F9 is used to selects a command by number. Just enter the command number and it fetches the command line for you. Command /? Shows help for that command.

Most Commonly Used Internal DOS Commands 1. DATE: Syntax is: DATE [/T] If you type DATE without parameters, it displays current date and prompts to enter new date. If you want to keep the same date just Press ENTER. DATE command with /T switch display current system date.

2.

TIME: Syntax is: TIME [/T] TIME with no parameters displays the current time and a prompt for a new one. TIME command used with /T switch displays the current system time.

3. CLS: It is used to clear the screen. Syntax is CLS 4.

COPY CON: It create a file in the existing directory.

Syntax is: COPY CON filename After that press Enter and start typing your text and after you're done typing your text, to save and exit hit F6 key or type CTRL+Z.

5.

TYPE: Display the contents of a text file. The syntax is: TYPE [drive:][path]filename

6. REN Change/modify the name of a file or files. Syntax is: REN [drive:] [path] filename1 filename2. Here, filename1 is source file for which you wanted to change the name, and filename2 is new file name.

7.

DIR: This command displays a list of files and subdirectories in a directory. Syntax is: DIR [drive:] [path] [filename] [/A[[:]attributes]] [/B] [/C] [/D] [/L] [/N] [/O[[:]sortorder]] [/P] [/Q] [/S] [/T[[:]time field]] [/W] [/X] [/4] /B display in bare format with no heading information or summary /D Displays file list sorted by column. /P Display page wise pausing after each screenful of information and prompts to press any key to continue. /S Displays files in specified directory and all subdirectories. /W Displays list width wise or wide list format.

8.

PATH: Displays the path that how we have come to the present position or sets a search path for executable files. Its Syntax is PATH

9.

VER: This command displays the version of DOS on your computer. Syntax is VER

10. DEL/ERASE: Used to delete one or more files. Syntax is DEL File Name [/P] [/F] [/S] [/Q] [/A[[:]attributes]] Names Specifies a list of one or more files or directories. Wildcards * and ? may be used to delete multiple files. * indicates group of unknown characters whereas using wildcard ? in file-names is for single unknown character. And using this command if a directory is specified, all files within the directory will be deleted. /P Prompts for (Y)es/(N)o confirmation before deleting each file. /F Used to force delete read-only files. /S Delete specified files from all subdirectories.

11. COPY: Copy one or more files to another file or location. Syntax is COPY [/D] [/V] [/N] [/Y | /-Y] [/Z] [/A | /B ] source [/A | /B] [+ source [/A | /B] [+ ...]] [destination [/A | /B]] Source specifies the file or files to be copied. Destination specifies the directory and/or filename for the new file or files. /V helps to verify new files to be written correctly. /Y If destination file already exists, this switch suppresses prompting to confirm overwrite.

12. MD: MD (or MKDIR) command is used to create a directory. Syntax is MD [drive:]path

13. CD: CD (or CHDIR) change directory and it allows to display the name of or change the current directory. Syntax is CD [/D] [drive:][path]

14. RD: RD (or RMDIR) command removes or deletes a directory. There are two conditions to remove any directory - (1) Directory to be removed should be empty. and (2) We should be outside the directory we are commanding to delete. Syntax is RD [/S] [/Q] [drive:]path /S removes a directory tree meaning it removes all directories and files in the specified directory in addition to the directory itself. And using /Q is the quiet mode that doesn't asks for ok approval to remove a directory tree.

Most Commonly Used External DOS Commands ATTRIB: With ATTRIB, you can view or change the attributes associated with a particular file. Syntax: ATTRIB +|- A +|-R +|-S +|-H pathname /S R Read Only S System File H Hidden

CHKDSK: The CHKDSK command checks the directory and file allocation table (FAT) of the disk and reports disk and memory status. CHKDSK also can repair errors in the directories or the FAT. Syntax CHKDSK drive:\path\filename.ext /F /V /F Fixes the FAT and other problems if errors are found. /V Shows CHKDSK’s progress and displays more detailed information about the errors that the program finds.

DEFRAG: Files become fragmented because of the way MS-DOS stores them on the disk. If parts of a single file are scattered over the disk, your disk drive requires more time to find and load all the pieces into memory. DEFRAG rearranges the files on your disk so that each is located in a series of contiguous clusters. Rearranging the files this way makes file access more efficient. Syntax: DEFRAG drive: /F /Q /U /S:order /B /H /F Fully optimizes specified disk. /Q Quick. /U Unfragments files, leaving space between files. /S Sort files by specified order.

DELTREE: By using DELTREE, you can delete an entire branch of your subdirectory tree. Unlike RD (or RMDIR), DELTREE deletes subdirectories that contain files. Syntax: DELTREE drive:\path /Y /Y Suppresses prompting for permission to delete each directory .

DISKCOPY: DISKCOPY copies the contents of one floppy disk to another on a track-for-track basis, making an exact copy. DISKCOPY works only with floppy disks. Syntax DISK COPY source: destination: /V

DOSKEY: DOSKEY enhances the usability of the DOS command line. It adds standard editing capabilities and the capability to recall recently used command lines.

FDISK: FDISK is a full-screen program that prepares a hard disk.. It sets up partitions on a hard disk as well as designates which partitions are used to start up the computer. On a new hard drive, you must run FDISK before you can use the FORMAT command on the drive.

FORMAT: The FORMAT command initializes a disk to accept files. FORMAT also checks the disk for defective tracks and (optionally) places DOS on the floppy disk or hard disk. Syntax: FORMAT drive: /Q /U/S /Q Performs a quick format by clearing only the FAT and root directory on the disk; this switch does not check the disk for bad sectors. /U performs an unconditional format for a floppy disk. Unconditional formatting destroys all data on a floppy disk, which means that you cannot unformat the disk. /S Places copies of the operating system files on the disk so that DOS can boot from disk.

EDIT: The EDIT command activates the DOS full-screen ASCII text-file editor. EDIT is very handy for writing batch files or making changes to your AUTOEXEC.BAT or CONFIG.SYS file.

HIMEM.SYS (device driver): If computer has more than 1MB of RAM installed, you should load HIMEM.SYS in CONFIG.SYS file. HIMEM.SYS is an extended memory manager. HIMEM.SYS should be one of the first device drivers. Syntax: DEVICE=drive:\path\HIMEM.SYS

MEM: MEM is a utility that displays the amount of used and unused memory, allocated and open memory areas, and all programs currently in the system. MEM can be enormously useful when you want to see just how your memory is being used, and whether you have enough space left for another resident program to be loaded high.

MOVE: You can use MOVE to move a file or group of files from one location to another or to rename subdirectories. Syntax To move a file or group of files, use the following format: MOVE source, source, ... destination /Y /-Y To rename a subdirectory, use the following format: MOVE old_dirname new_dirname

MSCDEX MSCDEX provides DOS access to CD-ROM drives. Syntax: MSCDEX /D:driversig

/D: driversig ... For each CD-ROM drive to which you want to assign a drive letter, you need to specify the driver signature (driversig) that you assigned to its device driver with the /D switch when you loaded it in your CONFIG.SYS file.

SCANDISK: The Scan Disk program can locate and fix errors on disks. Scan Disk also can perform a surface scan, which reads every sector on the disk to make sure that it is error free and readable. Syntax: SCANDISK drive:

TREE: The TREE command displays a visual representation of the subdirectory structure on your disk, which is often referred to as the directory tree. TREE can be useful for printing a map of your hard drive if you redirect its output to your printer. Syntax: TREE drive: path

UNDELETE: UNDELETE recovers files that were deleted with the DEL command if the file was deleted recently and little disk activity has occurred since the deletion. SYNTAX: UNDELETE pathname /LIST /ALL

UNFORMAT: The UNFORMAT utility can recover a disk that was inadvertently reformatted. You probably can unformat disks if they were not formatted with FORMAT /U. The UNFORMAT command works on both hard disks and floppy disks. Syntax: UNFORMAT drive:

XCOPY: XCOPY can copy groups of files and subdirectories from one disk to another. When copying large groups of files, XCOPY is somewhat faster than COPY because it reads more than one file at a time into memory. Syntax: XCOPY source destination /S /E

Networking

A network is a group of interconnected systems sharing services and interacting by means of a shared communications link. The individual systems must be connected through a physical pathway (called the transmission medium). All these systems must follow a set of common communication rules for data sending and receiving. The rules that manage computer communication are called protocols. Some of the primary reasons for networking PCs are as follows:


Sharing files




Sharing printers and other devices




Enabling common administration and security




Supporting network applications such as E-mail and database services

Network Models: Server-Based and Peer-to-Peer Server-based: A server-based network consists of a group of PCs (called clients) that request and receive network services from specialized computers called servers. Servers are generally higher-performance systems, optimized to provide network services to other PCs. (Some common server types include file servers, mail servers, print servers, and application servers.)

Peer-to-peer: A peer-to-peer network is a group of PCs (Each PC is called a Peer) that basically operate as equals. The peers share resources, such as files and printers. Each peer is responsible for its own security. Each peer is both a client (because it requests services from the other peers) and a server (because it offers services to the other peers). Small networks may work well in this configuration.

Network Components

Network Components ■ Client:

The device an end user uses to access a network ( work station, laptop, smart phone with wireless

capabilities)

■ Server: Serves up resources to a network. Example: e-mail access as provided by an e-mail server, web pages as provided by a web server, or files available on a file server. ■ Hub: A hub is an older technology that interconnects network components, such as clients and servers. Hub simply receives traffic in a port and repeats that traffic out all of the other ports.

■ Switch: Like a hub, a switch interconnects network components. Switch identifies devices connected to its ports. When traffic comes in a switch port, the switch forwards the traffic to appropriate port, but not for all of the other ports. This cuts down the traffic volume of a network. A switch is a Layer 2 device. A switch makes its forwarding decisions based on Media Access Control (MAC) address that physically burned into a network interface card (NIC).

■ Router: Router is a Layer 3 device. Router makes its forwarding decisions based on logical network addresses. Most modern networks use Internet Protocol (IP) addressing. When traffic comes into a router, the router examines the destination IP address of the traffic and, based on the router’s database of networks (the routing table), the router intelligently forwards the traffic out the appropriate interface. ■ Media: Through which data traffic flows. Media could be copper cable, fiber-optic Cable or air for wireless networks where radio waves travel through the media of air.

Networks Defined by Geography ■ Local-area network (LAN) ■ Wide-area network (WAN) ■ Campus-area network (CAN) ■ Metropolitan-area network (MAN) ■ Personal-area network (PAN)

Three Network Topologies The network topology describes the method used to do the physical wiring of the network. The main ones are bus, star, and ring.

1. Bus - Both ends of the network must be terminated with a terminator. 2. Star - All devices revolve around a central hub, which is what controls the network communications, and can communicate with other hubs. 3. Ring - Devices are connected from one to another, as in a ring. A data token is used to grant permission for each computer to communicate.

Ring Topology:

Ring topology, where traffic flows in a circular way around a closed network loop. A ring topology sends data, in a single direction, to each connected device in turn, until the intended destination receives the data.

Bus Topology:

Bus topology uses a cable running through the area requiring connectivity. Devices that need to connect to the network then tap into this nearby cable. Early Ethernet networks commonly relied on bus topologies.

Star Topology:

The star topology is the most popular physical LAN topology in use today, with an Ethernet switch at the center of the star and unshielded twisted-pair cable (UTP) used to connect from the switch ports to clients.

The OSI (Open Systems Interconnection)Model One of the most common ways of categorizing the function of a network technology is to state at what layer of the OSI model that technology operates. OSI model is to try to fit all the devices and protocols in their network into one of the OSI model’s seven layers. As previously stated, the OSI model is comprised of seven layers: ■ Layer 1: The physical layer ■ Layer 2: The data link layer ■ Layer 3: The network layer ■ Layer 4: The transport layer ■ Layer 5: The session layer

■ Layer 6: The presentation layer ■ Layer 7: The application layer

The physical layer is concerned with the transmission of data on the network.

The data link layer is concerned with packaging data into frames and transmitting those frames on the network, performing error detection/correction, identifying network devices with an address, and handling flow control. These processes are collectively referred to as data link control (DLC).

Media Access Control (MAC) is a 48-bit address assigned to a device’s network interface card (NIC). The address is in hexadecimal notation (for example: 58:55: ca: eb: 27:83). The first 24 bits are the vendor code. Logical Link Control (LLC)

The Network Layer is primarily concerned with forwarding data based on logical addresses.

The Transport Layer: ■ Transmission Control Protocol (TCP): It is a Connection-oriented transport protocol provides reliable transport, in that if a segment is dropped, the sender can detect that drop and retransmit that dropped segment.

■ User Datagram Protocol (UDP): A connectionless transport protocol provides unreliable transport, in that if a segment is dropped, the sender is unaware of the drop, and no retransmission occurs.

The Presentation Layer is responsible for the formatting of data being exchanged and securing that data with encryption.

■ Data formatting: Consider how text is formatted. Some applications might format text using American Standard Code for Information Interchange (ASCII), while other applications might format text using Extended Binary Coded Decimal Interchange Code (EBCDIC). The presentation layer is responsible for formatting the text (or other types of data, such as multimedia or graphics files) in a format that allows compatibility between the communicating devices.

■ Encryption: To send sensitive information over a network (for example, your credit-card number or bank password) add security for such transmissions, encryption can be used to scramble up (encrypt) the data in such a way that if the data were intercepted, a third party would not be able to unscramble it (decrypt). However, the intended recipient would be able to decrypt the transmission.

The application layer provides application services to a network.

It is top of the OSI stack, because its

functions are closest to the end user.

■ Application services: Supports services used by end-user applications like file sharing and e-mail.

■ Service advertisement: Some applications’ services (for example, some networked printers) periodically send out advertisements, making the availability of their service known to other devices on the network.

Ethernet Designation Codes

Designation

Description

10Base-2

10Mbps Ethernet over thinnet coaxial cable (RG-58) with a maximum segment distance of 185 meters

10Base-5

10Mbps Ethernet over thick (RG-8) coaxial cable with a maximum segment distance of 500 meters

10Base-T

10Mbps Ethernet over unshielded twistedpair cable. Maximum cable length (hub to network card) is 100 meters

100Base-TX

100Mbps Ethernet over Category 5 or better UTP cabling using two wire pairs. Maximum length 100 meters

1000Base-T

Gigabit Ethernet over Category 5 or better UTP cable Maximum length 100 meters

Cables:

Crimping a Category 5 Cable: 1. Remove Cable outer sleeve

2. Cut Excess length of wires after keeping in order as per colour code

3. Insert wires in to RJ45 Connector keeping in order as per colour code

4. Crimping with Tool

Straight Cable (System to Switch):

Cross Cable (System to System):

568B Wiring Standard for Straight Cable: Standards from Electronic Industries Association and Telecommunications Industries Association (EIA/TIA)

Structured Cabling Patch Panels: A patch panel is a wall-mounted unit (Generally kept inside a Rack) with a number of RJ-45 port connections on the front. It looks like a wall-mounted hub/switch without LEDs. The patch panel provides a connection point between network equipment such as switches.

Punch down tool inserting wires into an IDC:

Fiber-Optic Cable: Which sends light (instead of electricity) through an optical fiber. Using light instead of electricity makes fiber optics immune to EMI. Fiber-optic cables have higher range (maximum distance between networked devices) and higher data-carrying capacity. Lasers or lower cost light emitting diodes (LED) are used to inject light pulses into a fiber-optic cable. Fiber-optic cables are classified to two categories.

1. Multimode fiber (MMF) - wavelengths of light range of 850–1300 nm 2. Single-mode fiber (SMF) - wavelengths of light range of 1310–1550 nm SMF eliminates multimode delay distortion by having a core with small diameter So that it only permits one mode (one path) of propagation. SMF supports longer distance limitations than MMF. Since SMF has to be manufactured to very exacting tolerances, it is more expensive.

Common Fiber-Optic Connectors:

ST: Straight Tip (sometimes referred to as bayonet connector) because of the long tip extending. Locks with halftwist bayonet type of lock.

SC:

Defined as Subscriber Connector, Standard Connector, or Square Connector. Locks with push-pull connector similar to common audio and video plugs and sockets.

LC: Lucent Connector. Locks with flange on top, similar To RJ-45 connector. MT-RJ: Media Termination Recommended Jack Single connector for two fiber strands (transmit strand & receive strand)

Wireless Networking:

A wireless access point (AP) is both a transmitter and receiver (transceiver) device used for wireless LAN (WLAN) radio signals.

Basic WLAN Topology with a Wireless Router:

Wireless Routers Wireless router obtains an IP address via DHCP from the Internet service provider (ISP). Then, the router uses Port Address Translation (PAT) to provide IP addresses to devices attaching to it wirelessly or through a wired connection. The process through which a wireless client (for example, a laptop or a smart phone) attaches with a wireless router (or wireless AP) is called association.

Wireless Access Point Wireless access point (AP) interconnects a wired LAN with a WLAN, it does not interconnect two networks (for example, the service provider’s network with an internal network).

IEEE 802.11 Standards:

Transmission Methods: ■ Direct-sequence spread spectrum (DSSS): Modulates data over an entire range of frequencies using a series symbols called chips. ■ Frequency-hopping spread spectrum (FHSS): Allows the participants in a communication to hop between predetermined frequencies. Security is enhanced, because the participants can predict the next frequency to be used while a third party cannot easily predict the next frequency. FHSS can also provision extra bandwidth by simultaneously using more than one frequency.

■ Orthogonal frequency division multiplexing (OFDM): While DSSS used a high modulation rate for the symbols it sends, OFDM uses a relatively slow modulation rate for symbols. This slower modulation rate, combined with the simultaneous transmission of data over 52 data streams, helps OFDM support high data rates while resisting interference between the various data streams.

Types of WLANs: WLANs can be categorized based on their use of wireless APs. The three main categories are Independent Basic Service Set (IBSS), Basic Service Set (BSS), and Extended Service Set (ESS). An IBSS WLAN operates in an ad-hoc fashion, while BSS and ESS WLANs operate in infrastructure mode.

IBSS: WLAN can be created without the use of an AP. Such a configuration is called an IBSS, is said to work in an ad-hoc fashion. An ad-hoc WLAN is useful for temporary connections between wireless devices.

BSS: WLANs that have just one AP are called BSS WLANs. BSS WLANs are said to run in infrastructure mode, because wireless clients connect to an AP, which is typically connected to a wired network infrastructure. A BSS network is often used in residential and SOHO locations, where the signal strength provided by a single AP is sufficient to service all the WLAN’s wireless clients.

ESS: WLANs containing more than one AP are called ESS WLANs. Like BSS WLANs, ESS WLANs operate in infrastructure mode. When you have more than one AP, take care to prevent one AP from interfering with another. Non overlapping channels (channels 1, 6, and 11 for the 2.4-GHz band) should be selected for adjacent wireless coverage areas.

Sources of Interference A major issue for WLANs is radio frequency interference (RFI) caused by other devices Using similar frequencies to the WLAN devices. Physical obstacles can reflect WLAN transmissions. The following are some of the most common sources of interference:

■ Other WLAN devices: If two or more WLAN devices are in close proximity and use overlapping channels, those devices could interfere with one another. ■ Cordless phones: Several models of cordless phones operate in the 2.4-GHz band and can interfere with WLAN devices.

■ Microwave ovens: Older microwave ovens, which might not have sufficient shielding, can emit relatively highpowered signals in the 2.4-GHz band, resulting in significant interference with WLAN devices operating in the 2.4GHz band. ■ Wireless security system devices: Most wireless security cameras operate in 2.4-GHz frequency range, which can cause potential issues with WLAN devices.

■ Physical obstacles: Radio waves cannot propagate through a perfect conductor. ■ Signal strength: The range of a WLAN device is a function of the device’s signal strength.

Securing Wireless LANs ■ MAC address filtering: An AP can be configured with a listing of MAC addresses that are permitted to associate with the AP. If a malicious user attempts to connect via his laptop (whose MAC address is not on the list of trusted MAC addresses), that user is denied access.

■ Disabling SSID broadcast: An SSID (Service Set Identifier) can be broadcast by an AP to let users know the name of the WLAN. For security purposes, an AP might be configured not to broadcast its SSID.

■ Preshared key: To encrypt transmission between a wireless client and an AP (in addition to authenticating a wireless client with an AP), both the wireless client and the AP could be preconfigured with a matching string of characters of preshared key [PSK].

Security Standards: When configuring a wireless client for security, the most common security standards from which you can select are as follows: ■ Wired Equivalent Privacy (WEP) ■ Wi-Fi Protected Access (WPA) ■ Wi-Fi Protected Access version 2 (WPA2)

Connecting to Internet with ADSL Modem: The most important information to enter to get a DSL modem working is the Virtual Path Identifier (VPI) and Virtual Circuit Identifier (VCI) . These two numbers simply tell the DSL equipment on both ends that they should talk to each other, almost the same as replacing a dialed number. Each DSL provider uses a set of these two numbers.

Accessing ADSL Modem: ADSL Modem can be configured by browser based configuration tool. To access the ADSL modem type IP address of the modem. Normally most of the modems will have the default IP address: 192.168.1.1 or 192.168.0.1. and default User ID: admin, Default Password: admin or system. Refer to product manual for exact IP address. User ID & Password.

Configuring ADSL Modem: The most important settings needed are VPI & VCI values, User ID (Normally connection No.) and Password (Provided by ISP). Select channel mode as PPP to save User ID & Password to Modem. After entering these values Save/commit & Reboot the modem to work with these new settings. Other optional settings are DHCP range allotment; Wireless Settings like SSID, Broadcast SSID enable/disable, Encryption settings, setting a pre-shared key (Password for wireless network access).

Example: Settings for ADSL Modem:

Example: Settings for Cable Internet Connection

Internet Protocol (IP) Addressing IPv4 is comprised of 32 bits, IPv6 contains 128 bits. 32-bit IPv4 addresses are divided into four 8-bit octets IP address is divided into four separate numbers, each number represents an 8-bit portion of the 32 bits in the address. Because each of these four divisions of an IP address represents 8 bits, these divisions are called octets.

Binary Representation of Dotted Decimal IP Address: 10.1.2.3

IP address is composed of two types of addresses: (1) Network address & (2) Host address. Group of contiguous left-justified bits represent the network address, and the remaining bits (right-justified bits) represent the address of a host on a network. The IP address component that determines which bits refer to the network and which bits refer to the host is called the subnet mask. You can think of the subnet mask as a dividing line separating an IP address’ 32 bits into a group of network bits and a group of host bit.

Dividing an IP Address into a Network Portion and a Host Portion: A subnet mask (Class full) typically consists of a series of contiguous 1s followed by 0s, in total 32 bits. The 1s in a subnet mask correspond to network bits, while 0s in a subnet mask correspond to host bits.

Private IP Networks

Host bits of an IP address cannot be all 0s or all 1s. Therefore, the number of assignable IP addresses in a subnet can be determined by the following formula:

Where h is the number of host bits in a subnet mask

IP Addressing Components Default Gateway: If traffic is destined for a different subnet than the subnet on which the traffic originates, a default gateway needs to be defined. A default gateway routes traffic from the sender’s subnet towards the destination subnet. Domain Name System (DNS) server: When connecting to devices on the public Internet, a Domain Name System (DNS) server takes a FQDN (fully qualified domain names) and translates it into a corresponding IP address. Windows Internet Name Service (WINS): To convert the names of network devices into their corresponding IP addresses, WINS server used to resolve the network device name to a corresponding IP address. Example: The path of \\server1\hrdocs is in universal naming convention (UNC) form, where you are specifying a network device (server1) name and a resource (hrdocs) available on that device. Dynamic Host Configuration Protocol (DHCP): Statically assigning IP address information to individual networked devices can be time consuming, error-prone. Instead of static IP address, many networks dynamically assign IP address parameters to their devices by Dynamic Host Configuration Protocol (DHCP).

Automatic Private IP Addressing: If a networked device does not have a statically configured IP address and is unable to contact a DHCP server, it still might be able to communicate on network using Automatic Private IP Addressing (APIPA). The APIPA feature allows a networked device to self-assign an IP address from the 169.254.0.0/16 (Slashed Notation where /16 represents Subnet Mask of 255.255.0.0).

IP Version 6: With the worldwide depletion of IP versions 4 (IPv4) addresses, many organizations migrating their IPv4 addresses to IPv6 addresses. IPv6 increases the number of available IP addresses. An IPv6 address format, where X = a hexadecimal digit in the range of 0 – F XXXX: XXXX: XXXX: XXXX: XXXX: XXXX: XXXX: XXXX A hexadecimal digit is 4 binary bits in size. IPv6 address has eight fields, and each field contains four hexadecimal digits. The following formula reveals why an IPv6 address is a 128-bit address: 4 bits per digit * 4 digits per field * 8 fields = 128 bits in an IPv6 address.IPv6 addresses can be difficult to work with because of their size. So the following rules exist for abbreviating these addresses: ■ Leading 0s in a field can be omitted. ■ Contiguous fields containing all 0s can be represented with a double colon. (Note: This can be done only once for a single IPv6 address.) As an example, consider the following IPv6 address: ABCD: 0123:4040:0000:0000:0000:000A:000B Using the rules for abbreviation, the IPv6 address can be rewritten as follows: ABCD: 123:4040: A: B

Windows Server 2003 Administration

Server Roles:


Domain Controllers




File Servers




Print Servers




Web Server




Application Servers




Messaging Servers




Microsoft Management Console The MMC provides a common interface for a number of the services and tools that manage server. The MMC provides the container, and each service or tool operates as a snap-in within the console. The left pane in the MMC window is referred to as the console tree, and the right pane is referred to as the Details pane. When you select a particular item in the tree, its contents are displayed in the Details pane.

Local User Accounts and Groups You can create additional local user accounts that have varying degrees of access to the settings and service on the local machine. The default local user accounts are Administrator, Guest, and Support (used by Microsoft for support purposes). The Guest and Support accounts are also disabled by default.

Adding Local Users: 1. Right-click in an empty portion of the Details pane and select New User from the shortcut menu. 2.In the New User dialog box, Enter a username, a full name, a description, and a password for the new account.

Local User Groups: Local groups are typically used to impart certain access levels to the local users on the computer.

Adding users to a local group: 1. Right-click a particular group. Then select Add to Group from the shortcut menu. The group’s properties dialog box appears. 2. Click the Add button. Select Users dialog box opens. Type the user names that you want to add to the group in the Enter the Object Names box.

Understanding the Microsoft Networking Model Microsoft operating systems enable to share resources between computers without creating a domain. Set up a workgroup and share resources between computers which is termed a peer-to-peer network. Workgroups do not provide the security or scalability of the domain model and should be used only in very small office settings or for home networks. A domain is a logical grouping of computers and other devices that are managed as objects by a Windows domain controller. The domain maintains its own directory database of user accounts and controls all published resources within the domain, such as printers and shared files.

The domain classification of the Windows Server 2003 After the basic unit is the domain, next largest unit is the tree. A tree is a collection of child domains. The tree itself is defined by a root domain, which serves as the parent domain for the child domains that branch from the domain root. All the domains in the tree can get at the same set of resources, no matter which of the domains in the tree is actually hosting that resource. The largest administrative structure provided by the domain hierarchy is the forest. A forest is a collection of domain trees. You create a domain in the Windows Server 2003 environment by bringing the first domain controller online. Domain controllers are created by installing the Active Directory Services on a server running Windows Server 2003.

Using the Manage Your Server Tool: The Manage Your Server Tool is used to quickly assign a particular role to a server. (Another way is from Start menu, Administrative Tools, and then Configure Your Server Wizard)

…….Adding a Server Role 1)

Click Add or Remove Role near the top of the window.

2)

The next screen reminds you to connect your network medium and devices.

3)

The next screen provides a list of server roles. Select required server role.

Active Directory Active Directory is the directory service for Windows network. The Active Directory provides the namespace for domains and catalogs users, groups of users, computers, printers, and security policies in a centralized database that is replicated among domain controllers on the network. Each item such as a user or a group is referred to as an Active Directory object. When you create your first Windows Server 2003 domain, you are creating both a new forest and a new tree.

Installing Active Directory and Creating the Root Domain: Active Directory can be installed using the Configure Your Server Wizard from Start menu, Administrative Tools or you can start the wizard from the Manage Your Server window by selecting Add or Remove Role. You can start the Active Directory Wizard (to either create a domain controller or demote a domain controller to a member server) by dcpromo.exe

Configure Your Server Wizard Options:


You must have an NTFS volume on your server.




Make sure that modems, network cards, and other devices connected to the server.




After local area connections detection, the wizard opens Configuration Options screen.




For a First Server Select Typical Configuration (will provide DNS and DHCP Services).




Provide the full DNS name of your domain.




IP address of the DNS server provided by your Internet service provider.

Adding a Child Domain: After the root domain has been created, any number of child domains can be added to the domain tree. Installation Steps as follow:


Start the Configure Your Server Wizard




On the Server Role screen, select Domain Controller




To create a child domain select the Domain Controller for a New Domain option




On the next wizard screen select one of the following:

• Domain in a New Forest— This option creates a new forest, with the new domain controller serving as the root of the first tree in the forest. • Child Domain in an Existing Domain Tree— This enables you to place a child domain within an existing tree (this is the option you will choose to create a child domain). • Domain Tree in an Existing Forest— This option enables you to create a domain in an existing forest as the root of a tree.


Provide Administrator username and a password.




Type the name for the child name.




Continue remaining pages with default options. Using the Active Directory Management Tools: These tools enable you to add users and computers to the domain, manage the trusts among your various domains.




Active Directory Users and Computers: Manage user accounts, computers, groups.




Active Directory Domains and Trusts: Manage trusts between domains.




Active Directory Sites and Services: Manage the physical and logical structure of Windows Server 2003 network.

Working with Domain User Accounts: 

A local account is used to gain access to the local machine and its resources.



A domain account provides a user with the ability to log on to a domain and access the resources available on that domain.

Adding Users to the Domain:


Open the Active Directory Users and Computer snap-in.




Expand the domain node in the snap-in tree. Then select the Users folder.




Create a New User in the Current Container button on the Active Directory toolbar.




Enter a first name, initials, and a last name for the user.




In the User Logon Name box, type the username that use to log on to the domain.




Provide a password for the user and set properties related to password.

Setting User Account Properties • General: Edit the user’s display name, optional information such as the user’s telephone number, email address etc. This information will be available to other users on the network when they search the Active Directory. • Address: Provides the option of entering address information related to the user. • Account: Enables you to edit the username or the password options set for the Account . This tab also provides access to logon hour and computer logon settings You can also use this tab to set an expiration date for a user account.

Member Of: Used to view (and add or remove) the group memberships for the user. Terminal Services Profile: Used to set the path for the user’s Terminal Services profile.

Active Directory Groups


Domain Users: By default contains all users




Domain Admins: This group provides its members with the capability to perform administrative tasks on any computer in the domain.




Enterprise Admins: This group is for users who have the capability to administer the entire network




Account Operators: This group provides its members with the capability to create, modify, and delete user accounts and groups, which means that it gives its users access to the Active Directory.




Server Operators: Members of this group can create shares on a server and backup and restore files on the domain controller.




Print Operators: This group is for users who need to set up and manage printers. Backup Operators: Members of this group can back up and restore files Administrators: This group is for users who need to perform all the administrative tasks required on your domain controllers.

Users: This group is used to control the access to resources.

Windows Server 2003 Group Scopes The group scope refers to the level at which the group operates within the network.

• Universal group—A group that spans multiple domains and can have users from any of these domains as members.

• Global group— A group used to organize users in one domain. Global group can access resources in any domain in the Active Directory tree.

• Domain local group— A group created at the domain level and used to provide users with permissions to local resources (within the domain).

Creating Groups 1. Open Active Directory Users and Computers snap-in. 2. Click the icon Create a New Group on toolbar (or right-click in an empty space in the Details pane and select New. The Create New Object (Group) dialog box appears. 3. Type a name for the new group. 4. Choose the group type security for Domain Users. 5. Choose the scope for the new group: Domain Local, Global, or Universal.

Organizational Units Organizational Unit (OU) is an Active Directory object that serves as a domain container. This container can be used to hold users, groups, computers, and other OUs.

Creating Organizational Unit: Go to Active Directory Users and Computers snap-in tree, rightclick the domain node, select New on the shortcut menu and select Organizational Unit

Active Directory Sites Active Directory site is typically a physical location on the network that represents one or more IP subnets.

Creating a Site: Open Active Directory Sites and Services snap-in, Right-click the Sites folder and then select New Site.

Active Directory Replication and Sites: Replication is the process that allows domain controllers to keep Active Directory data consistent throughout the network. You can also specify the schedule for replication between sites. Right-click a site link in the IP or SMTP folders in the Active Directory Sites and Services snap-in. Select Properties from the shortcut menu. Select the General tab on the Properties dialog box.

Adding Client Computers to the Domain: Windows Server 2003 supports client computers with operating systems like DOS, Windows 3.11, Windows 9x/ME, Windows NT Workstation, Windows 2000 Professional, and Windows XP and Macintosh operating system. Computers running Windows NT, 2000, and XP must be added to the domain before the user can log on to the domain controller.

Using Active Directory to Add Computers to the Domain: Open the Active Directory Users and Computers snap-in, select the Computers node, right-click the Details pane, point at New, and then select Computer. The New Object–Computer dialog box opens.

Remote Installation Services Windows Server 2003 Remote Installation Services (RIS) used to install client operating system individually on desktop computers. Clients with a Boot ROM Chip or a Boot Disk will connect to the RIS server.

Installing the Remote Installation Service 1. Open the Add or Remove Programs applet in the Control Panel. 2. Select Add/Remove Windows Components. 3. Select Remote Installation Services, Continue with installation wizard and finish. 4. For RIS you must have both a DNS server and a DHCP server available on the network.

Configuring RIS 1. From Administrative Tools Select Remote Installation Services Setup. 2. On the next screen specify the path that will hold the installation files for the client. 3. Configure the RIS server to respond to clients requesting the service. 4. Provide the path to the CD-ROM that holds the Windows installation Disc. 5. Type in the name of the folder that will be created on the RIS server to hold the installation files. 6. Provide description for the installation files & continue to finish.


You can add any number of images to your RIS server from Active Directory Users and Computers snap-in RIS server - Properties - Remote Install tab - Advanced Settings - Images tab - Add




The RIS server can also deploy Windows clients using system images. An image of a Computer includes the operating system and the applications installed on the computer. You can create images using the riprep.exe utility from \Remote Install\Admin\I386 folder.

Creating the Remote Boot Floppy: Client computers boot to the RIS server over the network either with a boot ROM chip (Pre-Boot eXecution Environment, or PXE) or by using a boot disk. To create the boot disk Locate \Remote Install\Admin\I386 folder created for the RIS server, Run rbfg.exe file. The Microsoft Windows Remote Boot Disk Generator opens. To create the boot disk, place a formatted floppy disk in the server’s floppy drive and then click Create Disk.

Installing a Client Operating System: Go to BIOS settings on the computer to boot from Network / PXE ROM chip or boot disk. After booting the system to the network, the client should contact RIS server. After user login, installation of the client software proceed automatically.

Terminal Services: Terminal Server (server running Terminal Services) functions as an application server, providing applications that would not run as standalone software on the thin client. A thin client is software (used to refer computer) that allows a computer with a minimal hardware configuration to connect to an application server. Another aspect of Windows Terminal Services is Remote Desktop for Administration. This tool enables an administrator to connect to Windows Server 2003 remotely over an IP connection. This then enables to manage file and print sharing or other administrative tasks.

Adding the Terminal Server Role: 1. Start Manage Your Server window & select the Add or Remove Role link or from Administrative Tools Configure Your Server. 2. On the Server Role screen, select the Terminal Server role. 3. Continue summary and Restart.

Terminal Services Licensing: Each client that connects to the Terminal Server must have a license. These licenses are provided by a Terminal Server license server (server other than the Terminal Server).

Setting up a Terminal Server license server: 1. Add License server service to a server on the network and activate the service. 2. Acquire client access licenses from Microsoft and install them on the License Server.

Configuring Terminal Server: Select Start, Administrative Tools, Terminal Services Configuration

Configuring Connections: By default, a connection is created by the Remote Desktop/TCP protocol. This connection should be sufficient for all your remote connection users. The Settings are as follow:

Server Settings These settings basically provide the environment that Terminal Server clients will experience when connected.


Delete Temporary Folders on Exit




Use Temporary Folders Per Sessions




Licensing




Off for Terminal Server Sessions




Permission Compatibility




Restrict Each User to One Session

Session Directory: A session directory server keeps a database of Terminal Services clients and makes sure that they connect to the appropriate Terminal Server on the network.

Using the Terminal Services Manager The Terminal Services Manager enables you to view information related to Terminal Servers, capability to end sessions, log off users, and send messages to users.

Installing and Configuring the Remote Desktop Client To connect a client to the Terminal Server, the client computer needs to have the Remote Desktop Connection client installed on it. You can install the client over the network to any connected computer by sharing the C:\WINDOWS\System32\clients\tsclient folder. Run Setup executable file (msrdpcli.exe) from shared directory or from a storage media to install. After installation a connection can be made to a Terminal Server on the network. Settings for the connection are Terminal Server name / IP Address, resolution of the screen provided by the Terminal Server (to the client), and the selection of an application to automatically start. The Remote Desktop Connection client consists of five tabs:

General: Specify the name (or IP address) of the Terminal Server, username, password, and domain that the client will be logging on to.

Display: This tab enables you to set the display resolution and colors Local Resources: Configure settings such sound, keyboard hotkeys, connections to disk drives, printers, and serial ports can also be enabled or disabled on this tab. Programs: Specify an application to start automatically Experience: The experience relates mainly to speed of the session. You can configure the session to emulate a modem, broadband, or LAN connection.

Using Remote Administration: Another aspect of Terminal Services is the Remote Administration tool. This enables you to manage any server on your network that allows remote connections.To allow remote administration on a server, open the System Properties dialog box , select the Remote tab, select check box “All Users to Connect Remotely to Your Computer”.

Laser Printers

Laser Printer Working Steps: Step 1: Incoming data First, the computer sends data to the printer. Step 2: Drum preparation The single largest part of the laser printer is the drum, an aluminum cylinder coated with photosensitive material. In preparation for printing, the drum must be cleaned to remove any traces of previous pages. First, a rubber blade wipes the excess toner from the drum, and then erase lamps (in older models) or a charged drum (in newer models) electro statically clean it by neutralizing residual electrical charges on it.

After the cleaning, the printer conditions the drum to receive the next image by applying a uniform negative charge of -600v to its surface. The primary corona (in the toner cartridge) performs this function in some printers; in other models another charged drum does it. The primary corona is a thin wire; there are several corona wires involved in the print process. The primary corona must emit a charge of -6000v in order to apply a -600v charge to the drum. That is some seriously high voltage! Step 3: Drum writing The data in the printer’s memory is written to the drum using a laser on the photosensitive drum in certain spots, changing the electrical charge in those spots. As the drum cylinder rotates past the laser, it sweeps across the surface, turning on and off to neutralize certain areas to about -100v. These neutralized areas will be the spots where toner adheres to the drum later in the process and then transfers to the paper. Step 4: Paper feed Feed rollers draw the paper into the printer from the paper tray. Step 5: Toner pickup Steps 4 and 5 occur more or less simultaneously; as the paper is being drawn in, the toner is being applied to the drum. The toner cartridge contains a rotating, magnetic, metal-developing cylinder, a toner reservoir, and a height control mechanism that limits the amount of toner the cylinder can pick up at a time. Toner consists of plastic resin particles (the particles that melt to produce the image on paper) and iron oxide. The toner’s metal particles adhere to the magnetic cylinder, and the cylinder presents the toner to the drum as it passes by. The developing cylinder is charged to -600v, like the blank portions of the photosensitive drum, and the toner adhering to the cylinder also takes on that same charge. As the drum passes by the cylinder, the toner ignores all the areas charged to -600v because that’s the same charge as itself. It jumps off and clings to the areas with the lesser charge (-100v), however, and that’s what makes the toner stick to the drum. Step 6: Toner transfer to paper At this point, the image exists on the drum, complete with toner. As the paper feeds into the

printer, the transfer corona applies a +600v (positive) charge to the paper. When the paper passes by the drum, the -100v charged toner on the drum jumps off onto the positively charged paper. Then, the paper runs past a static charge eliminator. Step 7: Fusing the toner to the paper The image is now on the paper, but it’s just loose toner held in place. For permanent application, it must be fused. Fusing is basically melting the toner’s plastic particles so they stick to the fibers in the paper. The fuser roller is a nonstick cylinder with a heater inside it that heats the paper to around 330 to 355 degrees Fahrenheit.

The final part of the fusing assembly is the pressure roller. It’s a rubber roller that presses against the fuser roller; the paper feeds between it and the fuser roller on its way through the printer. The fuser roller can leave an indent on the softer pressure roller because of the heat it produces, so the printer’s internal software will rotate the assembly periodically to keep this from happening. That’s how a laser printer works. Each printer has built-in sensors at critical points that check whether the paper is in the right place for that step to occur. The printer knows how long it should take for the paper to move from one sensor to the next, and if the paper is delayed, the printer gives you a paper jam message.

Troubleshooting problems with laser printers Loose or smeared toner If the toner is loose (that is, not fused to the paper), the fuser is not melting the toner, and thus the toner is not fusing with the paper. Make sure the fuser is heating; if not, replace it. Similarly, smeared toner happens because the nonstick coating on the fusing roller is scratched or has baked-on debris. You can try to clean it with a soft cloth and alcohol, but make sure you let it cool down first! Vertical white areas To fix this problem, clean the corona wires. Why? This problem is caused by either the main corona or the transfer corona being covered with toner in a certain spot. A quick fix is to change the toner cartridge, even if it isn’t empty. Because the primary corona is located in the cartridge, this will correct problems with a dirty primary corona. To clean corona wires, use a special felt-lined tool that comes with your printer or use an alcohol-dipped cotton swab. But be very careful! Corona wires are thin and easy to break with too much pressure. To locate the primary corona, remove the toner cartridge and look for an exposed wire. The transfer corona’s location depends on the printer, but it is usually protected with a webbing of filament threads. Not all laser printers allow you access to the transfer corona, so check your manual if you can’t find it.

Gray mist If the white areas look like they have been lightly sprayed with a gray mist, making them look slightly dirty or dingy, the problem is also likely to be a dirty corona wire. (See the preceding section.) This can also be the result of turning the printer’s print density control up too high. The newer the drum, the lower this setting can be. As the drum ages, you must turn up the print density control higher to achieve sharp black printouts. However, if you turn it up too high, the entire page acquires a dirty gray tinge. Some printers include the drum in the toner cartridge, so you get a new one each time you change toner. On other printers, the drum is separate, and you must eventually replace it when it wears out. Printing not dark enough or varied in darkness If the print is a dismal gray rather than a sharp black, you are probably almost out of toner. This can manifest itself evenly across the entire page or in splotches or stripes, depending on the printer. Sometimes you can wring a little bit more out of a toner cartridge by taking it out and gently shaking it from side to side (never up and down, as toner can spill out). You can also try turning up the printer’s contrast adjustment, if it has such a knob (usually on the back side if it exists). Faded print can also result from a dirty corona wire, because a dirty wire inhibits a full electrical charge from being passed. If the printouts are consistently varied in density, and you have to frequently remove the toner cartridge and shake it to redistribute the toner inside it, make sure the printer is sitting on an even, flat surface.