The Deal

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Introduction Introduction toto

ComputersComputers

Hardware Concepts-IHardware Concepts-I

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Information TechnologyInformation Technology

The branch of technology devoted to:

(a) The study and application of data and the processing thereof; i.e., the automatic acquisition, storage, manipulation (including transformation), management, movement, control, display, interchange, transmission or reception of data and

(b) The development and use of the hardware, software, and procedures associated with this processing.

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Model of an Information SystemModel of an Information System

DATA

H/W

ProceduresStored Data

S/W

People

INFORMATION

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The The Five GenerationsFive Generations of Computers of Computers First Generation - 1940-1956:First Generation - 1940-1956:

Vacuum Tubes for Circuit for Circuit Magnetic drums for Memory Enormous in size, taking up entire rooms Very expensive Used a great deal of electricity, generated a lot of heat,

which was often the cause of malfunctions Relied on machine language to perform operations They could only solve one problem at a time. Input was based on punched cards and paper tape Output was displayed on printouts. E.g..: UNIVAC and ENIAC

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The The Five GenerationsFive Generations of Computers of Computers Second Generation - 1956-1963:Second Generation - 1956-1963:

Transistors replaced vacuum tubes Allowing computers to become smaller, faster, cheaper,

more energy-efficient and more reliable than their first-generation predecessors.

Punched cards for input and printouts for output. Symbolic, or assembly languages High-level programming languages, such as early

versions of COBOL and FORTRAN. Stored instructions in their memory The first computers of this generation were developed for

the atomic energy industry.

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The The Five GenerationsFive Generations of Computers of Computers Third Generation - 1964-1971:Third Generation - 1964-1971:

Integrated circuit Transistors were miniaturized and placed on silicon

chips, called semiconductors, which drastically increased the speed and efficiency of computers

Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

Keyboards for input Monitors for output Interfaced with an operating system, which allowed the

device to run many different applications at one time with a central program that monitored the memory.

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The The Five GenerationsFive Generations of Computers of Computers Fourth Generation - 1971-Present:Fourth Generation - 1971-Present:

Microprocessor, where thousands of integrated circuits were built onto a single silicon chip

Fit in the palm of the hand The Intel 4004 chip, developed in 1971, located all the

components of the computer - from the central processing unit and memory to input/output controls - on a single chip.

In 1981 IBM introduced its first computer for the home user,

And in 1984 Apple introduced the Macintosh Linked together to form networks, which led to the

development of the Internet. Development of GUIs, the mouse and handheld devices

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The The Five GenerationsFive Generations of Computers of Computers Fifth Generation - Present and Beyond:Fifth Generation - Present and Beyond:

Based on artificial intelligence, are still in development Though there are some applications, such as voice

recognition, that are being used today. The use of parallel processing and superconductors is

helping to make artificial intelligence a reality. Quantum computation and molecular and

nanotechnology will radically change the face of computers in years to come.

The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization

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Classification of Computers based on SizeClassification of Computers based on Size

Super computersSuper computers These are the largestlargest and fastest fastest computers available. Not used for commercial data processing. Instead used in specialized area such as defence, defence,

aircraft design, computer generated movies etc.aircraft design, computer generated movies etc. They can process 64 bits64 bits or more at a time. Processing speed ranges from 10,000 million10,000 million

instructions per second to 1.2 billion1.2 billion instructions per second.

They can support up to 10,000 terminals10,000 terminals at a time.

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Main frame computersMain frame computers These are less powerful and cheapercheaper than super

computers. However they are big general-purpose computers

capable of handling all kinds of scientific and business applications.

They can process at several million instructions per second.

They can support more than 1000 remote terminals1000 remote terminals at a time.

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Mini ComputersMini Computers This type of computer performs data processing

activities in the same way as the mainframe but on a smaller scalesmaller scale.

The cost of minis is lower. It costs about Rs 5 lacs to 50 lacs. Data is usually input by means of a keyboard. It consists of a C.P.U., several disk drives, a high speed

printer and number of terminals

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Micro computersMicro computers It is a full fledged computer system that uses a

microprocessor as its CPU. Also called personal computer systemspersonal computer systems.

Now a days computer are also categorized as: ServerServer

It provides services to other computing systems called –clients- over a network.

WorkstationWorkstation Between minicomputer and microcomputer- in terms of

processing power. Looks like PC and used by one person.

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CComponents of PComponents of PC

Central Processing Unit (CPU)

Primary storage

Input devices

Output devices

Communication devices

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Block Diagram of ComputerBlock Diagram of Computer

CPU

PrimaryStorage

SecondaryStorage

CommunicationsDevices

OutputDevices

Input Devices

Buses

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Central Processing Unit (CPU)Central Processing Unit (CPU)

Area of the computer system,

That manipulates symbols, numbers, and letters,

And controls the other parts of the PC

Two components of CPU: Control UnitControl Unit Arithmetic Logic UnitArithmetic Logic Unit

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Control UnitControl Unit Component of the CPU that controls and that controls and

coordinates the other parts of the computer coordinates the other parts of the computer systemsystem

Reads and interprets program instructions Direct internal processor components Moves programs and data in & out of RAM Components

Decoder: to decode instruction Accumulator: to store results Registers: to store instruction, data

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Arithmetic-logic Unit (ALU)Arithmetic-logic Unit (ALU)

Component of the CPU

That performs the principal logic and arithmetic operations of the computer.

Performs computations (+,-,*, /)

Performs logic operations (>, <, =, AND, OR, XOR)

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Primary Storage (Main Memory)Primary Storage (Main Memory)

Part of the computer that temporarily stores Part of the computer that temporarily stores program instructions and data being used by the program instructions and data being used by the instructionsinstructions

It is mainly categorized into two types: RAMRAM: Random Access Memory ROMROM: Read Only Memory: Read Only Memory

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RAM (Random Access Memory)RAM (Random Access Memory) Primary Storage, accessed at electronic speeds Volatile (electrical interruption loses data) The program can randomly select and use any of the

storage locations of RAM. Data and programs can be stored in RAM from input

devices or auxiliary storage devices. The stored data can be retrieved and displayed on a CRT

screen or printed on a printer Data stored in RAM can be changed by a user using

instructions within a computer program during computer processing.

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RAM (Random Access Memory)RAM (Random Access Memory)

Two types of RAM DRAM: Dynamic RAMDRAM: Dynamic RAM

It is dynamic because each memory cell quickly loses its charge, so it must be refreshed hundreds of times each second to prevent data from being lost.

SRAM: Static RAMSRAM: Static RAM It is like DRAM, but it is a lot faster, larger and more

expensive. It is static because it does not need to be continually

refreshed. Because of its speed, it is used in a special area of memory

called Cache.

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ROMROM Read Only Memory

Primary Storage

Non-Volatile

It is used for storing micro-program control instructions that cause the machine to perform certain operations.

With ROM, data is recorded in the memory when the memory is manufactured.

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ROMROM The data or programs which are stored in ROM can be

read and used but they cannot be altered.

The information form the memory may be read but fresh information cannot be written into it.

ROM BIOS is one such example.

But now a days some alterations can be done in the following forms of ROM: PROM – Programmable read only Memory EPROM – Erasable Programmable read only memory EEPROM – Electrically Erasable Programmable Read Only

Memory.

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Cache MemoryCache Memory Cache is special area of high speed memory that is

located between the CPU and main memory.

When the processor needs data, it checks high-speed cache first to see if the data is there, if not, the processor then retrieves the data from the main memory.

On some systems, cache memory is four times as fast as regular main memory.

However, cache costs six times as much as main memory