Looking Inside The Machine

	Sign In Sign-Up

NokhraNetwork

HOME

Learning Section:
Part-1

Looking Inside The Machine
[Basic Concept Of Hardware]

Computer: Computer are now needs in every sphere in human activity and bring many change in constructions, Architectures, Medicine, Space, Vehicles, Aid in Teaching, Grade sheet in Examination and result process, Inventory Controls, Design in buildings, bridge etc.

The creativity of computer in confined by the limitation of human imaginary.

What is a Computer System: The term “ Computer” is a device made up of a Combination of electronic and electromechanical components. The Computer has no intelligence it is just Physical equipment. The computer can’t work until it is connected to the different parts of Computer system. There are six elements of the Computer System.

1. Hardware,

2. Software,

3. Data/ Instruction/Information,

4. People,

5. Procedure,

6. Communication

Hardware: Computer hardware can be divided into five categories: (1) The computer itself - the hardware has many parts, but each piece falls into one of five categories:

1. Processing Hardware

2. Input Device

3. Output Devices

4. Storage Devices

5. Communication.

PROCESSING HARDWARE:

The Processor: The complex procedure that transforms raw data into useful information is called processing. To perform this transformation, the computer uses two components; the processor and memory. The processor is like the brain of the computer, the part that organizes and carries out instructions that come from either the user or the software, In a personal computer, the processor usually Consists of one or more microprocessors, which are slivers of silicon or other material etched with many tiny electronic circuits. The microprocessor is plugged into a circuit board- a rigid rectangular card containing the circuitry that connects the processor to the other hardware. The circuit board to which the microprocessor is connected is called the motherboard.

In some powerful computers, the processor consists of many chips and the circuit boards on which they are mounted. The term central processing unit (CPU) refers to a computers processing hardware, whether it consists of a single chip or several circuit boards. This “vital organ” occupies an amazingly small space in a PC.

The central processing unit (CPU) is the brain of the computer. It reads and interprets software and coordinates the processing activities that must take place. The design of the CPU affects the processing power and the speed of the computer, as well as the amount of main memory it can use effectively. The CPU is also referred to as a processor.

Main memory can be thought of as an electronic desktop. Main memory is also called random access memory (RAM), internal memory, primary storage, or just memory. All instructions and/or data ready for processing are held in memory. The more desk surface you have in front of you, the more you can place on it. Similarly, the amount of memory available determines whether you can run simple or sophisticated software; a computer with a large memory is capable of holding the thousands of instructions that are contained in more sophisticated software programs. In addition, a lot of memory allows you to work with and manipulate gradate amounts of data and information at one time. Typically, the more main memory you have in your computer, the more you can accomplish. However, since RAM is volatile- that is, all contents are lost when the computers power is shut off – the data and instructions should be saved to a storage device before the computer is turned off (and to protect data in case of a power outage). The processor block called itself CPU-Central Processing Unit.

Details:

The Control Unit: All the computers resources are managed from the control unit you can think of the control unit as a traffic cop directing the flow of data it is the logical hub of the computer.

The CPUs instructions for carrying out commands are built into the control unit. The instructions, or instruction set, list all the operations that the CPU can perform. Each instruction in the instruction set is expressed in microcode- a series of basic directions that tell the CPU how to execute more complex operations. Before a program can be executed, every command in it. Must be broken down into instructions that correspond to the ones in the CPU’s instruction set. When the program is executed, the CPU carries out the instructions, in order, by converting them into microcode. Although the process is complex, the computer can accomplish it at an incredible speed, translating millions of instructions every second.

Different CPUs have different instruction sets, Manufacturers, however, tend to group their CPUs into “ families” that have similar instruction sets. Usually, when a new CPU is developed, the instruction set has all the same commands as its predecessor plus some new ones. This allows software written for a particular CPU to work on computers with newer processors of the same family-a design strategy known as upward compatibility. Upward compatibility saves consumers from having to buy a whole new system every time a part of their existing system is upgraded.

The reverse is also true. When a new hardware device or piece of software can interact with all the same equipment and software its predecessor could, it is said to have downward, or backward, compatibility.

The Arithmetic Logic Unit: Because all computer data is stored as numbers, a lot of the processing that takes place involves comparing numbers or carrying out mathematical operations. In addition to establishing ordered sequences and changing those sequences, the computer can perform only two types of operations: arithmetic operations and logical operations, Arithmetic operations include addition, subtraction, and division. Logical operations include comparisons, such as determining whether one number is equal to, greater than, or less than another number. Also, every logical operation has an opposite. For example, in addition to “equal to” there is “not equal to” Table 1 shows the symbols for all the arithmetic and logical operations.

It is important to remember that some of the logical operations can be carried out on text data. For example, when you want to search for a word in a document, the CPU carries out a rapid succession of “equals” operations to find a match for the sequence of ASCII codes that make up the word for which you are searching.

Many instructions carried out by the control unit involve simply moving data from one place to another-from memory to storage, from memory to the printer, and so forth. However, when the control unit encounters an instruction that involves arithmetic or logic it passes that instruction to the second component of the CPU, the arithmetic logic unit, or ALU. The ALU includes a group of registers- high-speed memory locations built directly into the CPU that are used to hold the data currently being processed. For example, the control unit might load two numbers from memory into the registers in the ALU. Then, it might tell the ALU to divide the two numbers (an arithmetic operation) or to see whether the numbers are equal (a logical operation).

Registers – Staging Areas for Processing: The control unit and the ALU also contain registers or special areas that enhance the computer’s performance. Registers are high – speed staging areas that temporarily store data during processing and provided working areas for computation. It could be said that main memory holds material that will be used “a little bit later”. Registers hold material that is to be processed “immediately”. The computer loads the program instructions and data from main memory into the registers just before processing, which helps the computer process faster. (There are several types of registers, including an instruction and address register, register, a storage register, and an accumulator.)

In brief, processor’s chips are created like this:

1. A large drawing of electrical circuitry is made that looks something like the map of a train yard. The drawing is photographically reduced hundreds of times so that it is of microscopic size.

2. That reduced photograph is then duplicated many times so that, like a sheet of postage stamps, there are multiple copies of the same image or circuit.

3. That sheet of multiple copies of the circuit is then printed (in a printing process called photography) and etched onto a 3-inch-diameter piece of silicon called a wafer.

4. Subsequent printings of layer after layer of additional circuits produce multilayered and interconnected electronic circuitry built above and below the original silicon surface.

5. Later an automated die-cutting machine cuts the wafer into separate chips, which are usually, less than 1-centimeter square and about half a millimeter thick. A chip, or microchip, is tiny piece of silicon that contains thousands of microminiature electronic circuit components, mainly transistors. (A transistor is like an electronic “gate”, or switch, that opens and closes to transmit or stop electronic current. It can alternate between “on” and “off” millions of times per second.)

6. After being tested, each chip is then mounted in a protective frame with extruding metallic pins that provided electrical connections through wires to a computer or other electronic device.

OPERATION PERFOMED BY ALU:
Arithmetic Operations	Logical Operations
+ add	=, ¹ equal, not equal
- subtract	> > greater than, not greater than
* multiply	<< less than, less than
/ divided	³ ³ greater than or equal to, not greater than or equal to
^ raise by a power	£ £ less than or equal to, not less than or equal to

The famous company “INTEL” produced the following types of processor: -

1. Intel 8086/808 (XT-Extended Technology)

Clock speed : 4-8 MHz. –1979.

2. Intel 80286 (AT-Advance Technology)

Clock speed : 16-20 MHz. –1981.

3. Intel 80386/80386 DX (With Coprocessor)

Clock speed : 25/33 MHz. –1987

4. Intel 80386 SX (Without Coprocessor)

Clock speed : 40 MHz. –1987.

5. Intel 80486/80486 DX (With Coprocessor)

Clock speed : 60/66 MHz. –1991.

6. Intel 80586 Pentium (With MMX Technology)

Clock speed : 166 MHz. –1993.

7. Intel Pentium Pro (With MMX Technology)

Clock speed : Up to 200 MHz. –1993.

8. Intel Pentium-2 (With MMX Technology)

Clock speed : 250-450 MHz.

9. Intel Pentium-3 (With MMX Technology)

Clock speed : 500-850 MHz. – 1998.

* Another company – Intel Celeron – 1998.

Mega Hertz:

1 MHz. = 1 million (100,00,00) wave/Sec.

1 Second = 1000 Millie Second.

1 Second = 100,000 micro Second.

1 second = 100,000,000 Nano second.

1 Second = 100,00,00,00,00,000 pico second.

Memory: Memory is the computers electronic scratchpad. Programs are loaded into and run from memory. Data used by the jprogram is also loaded into memory fjor fast access. The mjost common type of jmemory is called random access memory or RAM (see Figure 1.4) As a result; the term memory is commonly used to mean RAM.

Perhaps the most important thing to remember about RAM is that it is volatile , so it nseeds a constant supply of power. When you turn off a computer, everything in RAM disappears. As you will soon learn, this is why you frequently have to save everything you are working on to a storage device.

One of the most important factors affecting the speed and power of a computer is the amount of RAM it has. Generally, the more RAM has a computer, the more it can do. The most common measurement unit for describing a computer’s memory is the byte – the amount of memory it takes to store a single character. When people talk about memory , the numbers are often so large that it is useful to use a shorthand term to describe the values:

· Kilobyte (KB) approximately 1,000 bytes,

· Megabytes (MB) approximately 1,000,000 bytes,

· Gigabytes (GB) approximately1,000,000,000 bytes

Today’s personal computers commonly have 16 to 64 million bytes of memory, or 16 to64 MB.

INPUT HARDWARE:

The function of input hardware is to collect data and convert it into a form suitable for computer processing. An example of data for input would be sales figures for different musical instruments sold by different sales people in different states.

Keyboard: The most common input hardware is keyboard by which we can input data/information in to the computer. It looks like a type writer. Two variants of keyboards .

1^st variant: - The Number of keys are 84-86 in the IBM-PC Student type writing keys.

2^nd variant: - 1o1-1o2 writing keys. There are Five Common feature of Standard keyboard

1. Standard type write keys.

2. Cursor Movement keys.

3. Numeric keys.

4. Function keys

5. Special purposee keys .

MOUSE: A mouse is an input pointing device that is rolled about on a desktop to direct a pointer on the computer display screen. A mouse pointer is a device that indicates the position of a mouse on the displkay screen.

Top side: In top sides there are one, two or three button. Depending on the software these button are used for common functions or special purposes like clickjikng and Dragging . The mouse Languages

1. Point

2. Click

3. Double-click

4. Drag

5. Drop

6. Pointing and shoot.

JOYSTICK: It is also input device consist a vertical handle like gearshift lever mounted with one or two (up to 4) buttons. The purpose of this device is for playing Games and some computer aided design (CAD).

Scanner: Through scanner we can input data/information/image in to the computer in a typing list. Scanner read this information and convert them electron copy which is work latter in the computer by using the special programs. Scanner scans the image and transferred them into ASCII (American Standard Code for Information Interchange) code. There are two types of scanner –

1. Flat – bed;

2. Roller – bed.

Flat – bed: This type of scanner is work like as a photocopier machine.

Roller – bed: By the use if this scanner the images are passed over the roller where it is capture.

Modem: Modem is a communication device. Modem is communicated between the computer and the telephone lines, which converted computer’s digital signal to analog signal for telephone and VICE versa (telephones analog signal to digital signal for computer). At first it modulate the signal and then demodulate. There are two types of Modem:

1. Internal;

2. External.

Internal: Modem, which is into the computer system and used power supply from PC.

External: It is independent hardware, which uses own power supply.

There are also many kind of input devices in market –

· Trackballs,

· Touch screen

· Light pens

· Digital tables

· Pen – based system

· Smart Card & Optical Card

· Voice Recognition System

· Audio input device

· Electronic Camera

· Sensor.

Printer: Printer is the most common output device (hardcopy output device). Two types of printer used with microcomputer.

1. Impact Printer;

2. Non Impact Printer.

Impact Printer Non – Impact Printer

Dot Metrics, Daisy Wheel, Line printer. Laser Ink Jet Thermal Transfer

1. Dot Matrix: DMP is the most common type of impact printer. Dot metrics works as a mechanism of typewriter. With creating image tike dot. DMP metrics printer have print head with pins that strike an ink ribbon and forming character on image. May be 9 pins, 18 pins, 24 pins or 32 pins.

2. Daisy wheel printer: DWP has a removal print head consorting of spokes. Each spoke ends has raised character. The wheel move and align the desire character width next printing position and hammer strike the spoke end.

There are another type of Impact printer which is used for large computer installation called line printer. 2 types:

a) chain printer

b) Band “

Non- Impact printer: Non- impact printer is fast and quieter the than IP. NIP forming character or image without having direct physical contact, between the printing mechanism and paper.

Mechanism of Lasar printer.

Laser printer works as a mechanism of dot matrix of creating image. These images created on a charged drum treated with magnetically charged ink like toner (powder) and then treated from drum to paper. A stream of laser beam bounced of a rotating mirror millions time per second and then passed to the lenses and thin hits the drum. The spot where laser beam hits become neutralized enable the toner to strike to them onto the paper. After that this paper passed through the heat and pressure and we get a desire printing copy.

c) Ink- jet printer: Like laser and DMP, Ink jet printer also from image. IJP spray small electrically charged droplets of ink from 4 Nozzle through holes ink a matrix in high speed into paper.

Mechanism of Ink-Jet printer

An upgradeable version of a BJC is call bubble-Jet printer 128 tiny nozzle. By using this types of printer we get bent printing quality as well as graphics and texts.

Storage Device: It is possible for a computer to function with just processing memory input and out put devices To be really useful. However it also needs a place to keep program files and related data when ink is not using them, The purpose of storage is to hold data.

It is helpful to think of storage as an electronic file cabinet and to think of RAM as an electronic worktable, When you need to work with a program or a set of data, the computer locates them in the file cabinet and puts a copy on the table, After you have finished working with the program or data, you put the new version into the file cabinet, There are three major distinctions between storage and memory:

1. There is more room in storage than in memory just as there is major room a file cabinet than there is on a tabletop.

2 Storage retains its contents when the computer is turned off, whereas the programs or the data you put into memory disappear when you shut down the computer.

3 Storage is much cheaper than memory.

The most common storage medium is the magnetic disk, A disk is a round, flat object that spins around its center, Read/write heads, which are similar to the heads of a tape recorder or VCR, float above and below the disk near its surface,

The device that holds a disk is called a disk drive. Some disks are built into the drive and are not meant to be removed, and other kinds of drives allow you to remove and replace disks. Most personal computers have a non-removable hard disk. In addition there are usually one or two diskette drives, which allow you to use removable diskettes. Typically, a hard disk can store far more data than a diskette can so the hard disk serves as the computers primary filing cabinet. Diskettes are used to load new programs or data onto the hard disk to trade data with other users and to make backup copies of the data 0n the hard disk.

Because you can remove diskettes from a computer, they are encased in a plastic or vinyl cover to protect them from fingerprints and dust. The first diskettes commonly used in the late 1970s, were 8-inch diskettes (they weedier 8 inches in diameter) because the vinyl cover was very thin, the diskette was flimsy, or floppy. Hence, came the name of floppy disk. Next came the 5.25-inch diskettes that were common in the early PCs. Finally, the 3.5-inch diskette with its hard plastic shell appeared.

Other types of storage devices include CD-ROM drives, tape drive, optical drives, removable hard drives, and many others. The CD-ROM drive is the most common type after the hard and diskette drives. Compact disks or CDs, are a type of optical storage device, identical to audio CDs, that can store about 60 MB, or about 450 times as much information as a diskette. The type used in computers is called a CD-ROM, which stands for “Compact disk read only memory”. The name implies that you cannot change the information on the disk, just as you cannot record over an audio CD.

Hard Disks:

Hard disks are rigid metal platters that hold data as magnetized spots. Usually a microcomputer hard disk disk drive is built into the system unit but external hard disk drives are available as are removable hard disk cartridges. Large computers use removable hard disk packs, fixed disk drives, or RAID storage systems.

In microcomputers, hard disks are one or more platters sealed inside a hard disk drive that is built into the system unit and cannot be removed The drive is installed in a drive bay, a slot, or opening, in the computer cabinet. From the outside of a microcomputer, a hard disk drive is not visible it looks simply like part of the front panel on the system cabinet Inside however is a disk or disks on a drive spindle read/write heads mounted on an actuator (access) arm that moves back and forth and power connections and circuitry (See Figure 4.12)The disks may be 5 inches in diameter, although today they are more often inches with some even smaller. The operation is much the same as for a floppy disk drive, with the read/write heads locating specific pieces of data according ;to track and sector.

Hard disks have a couple of real advantages over diskettes and at least one significant disadvantage,

Advantages: capacity and speed we mentioned that hard disks have a data storage capacity that is significantly greater than that of diskettes. Microcomputer hard disk drives typically hold 4-5 gigabytes and some newer ones are in the 10-30 gigabyte range.

Disadvantages: Possible “head-crash”; In principle a hard disk is quite a sensitive device. The read/write head does not actually touch the disk but rather rides on a cushion of air about 0.000001 inch thick. The disk is sealed from impurities within a container, and the whole apparatus is manufactured under sterile conditions. Otherwise, all it would take is a smoke particle, a human hair, or a fingerprint to cause what is called a head crash.

A head crash happens when the surface of the read/write head or particles on its surface come into contact with the disk surface, causing the loss of some or all of the data on the disk. An incident of this sort could , of course, be a disaster if the data has not been backed up. There are firms that specialize in trying to retrieve (for a hefty price) data from crashed hard disk, though this cannot always be done.

In recent years, computer magazines have evaluated the durability of portable computers containing hard disks by submitting them to drop tests. Most of the newer machines are surprisingly hardy. However, with hard disks – whether in desktop or in portable computers – the possibility of disk of disk failure always exists.

Hard disk Variations and Portability:
          If you have an older microcomputer or one with limited capacity in its existing hard disk, some variations are that can provide additional power or portability:
         Miniaturization: Newer hard disk drives are less than half the height of older drives (1¹/₂ inches versus 3¹/₂ inches high) and so are called half – height drives. Thus, you could fit two disk drives into the bay in the system cabinet formally occupied by one.
    In addition, the diameter of the disks has been getting smaller. Instead of 5¹/₄ or 3¹/₂ inches, some platters are 2.5, 1.8, or even 1.3 inches in diameter. The half-dollar-size 1.3 Kittyhawk microdisk , which is actually designed for use in handle computers, holds 21 megabytes of data.

Updating Book