IT & ITES COPA INTRODUCAION TO COMPUTER COMPONENTS
Introduction to computers
Objectives : At the end of this lesson you shall be able to
· Define and classify computers
· List the advantages and limitations of computers
· List the application of computers
· Describe the voltages and currents in the computers.
Computer – Definitions
A computer is an electronic machine, operating under the control of instructions stored in its own memory that can accept data (input) produce results (output) and store the results for future use.
Technically a computer is a programmable machine. This means it can execute a list of programmed instructions and respond to new instructions that it is given.
History of Computer
Charles Babbage’s Machine
The working principles of today’s computers were provided by an English Mathematician Charles babbage around 1833’s invented a machine called the “analytical Engine”. A machine which could calculate and print tables of functions using limited techniques.
The analytical Engine had four parts. A mill which was the section which did the calculations essentially the CPU. The store were the information was kept recorded essentially the memory the reader which would allow data to be entered using punched cards essentially the keyboard and the printer.
Hence Charles babbage is considered as the “Father of the Computer” as in
The generations of computers are characterized by a major technological development that fundamentally changed the way computers operate. Resulting in increasingly smaller, cheaper more powerful and more efficient and reliable devices the various generations of computers are listed below.
First generation
(1946-1954)
First generation (1946-1954) in 1946 the digital computer using electronic calves (Vacuum tubes ) are known as first generation computers. The first computer to use electronic valves i.e. vacuum tubes. The high cost of vacuum tubes prevented their use for main memory. The stored information in the form of propagating sound waves.
The vacuum tube consumes a lot of power. These computers were large in size and writing programs on them was difficult. Some of the computers of this generation were.
Mark I : IBM Automatic Sequence controlled Calculator (ASCC), called the mark I by Harvard University was an Electro-mechanical computer . Mark I is the first machine to successfully perform a long services of arithmetic and logical operation. Mark I is the first generation computer.
ENIAC : it was the first electronic computer built in 1946 at university of Pennsylvania USA by John Eckert and John Mauchy. It was named electronic Numerical Integrator and calculator (ENIC). The ENIAC was 30-50 feet long, weighted 30 tons, contained 18,000 vacuum tubes 70,000 resisters 10,000 capacitors and required 150,000 watts of electricity. Today computer is many times as powerful as ENIAC still size is very small.
EDVAC: it stands for Electronic Discrete Variable Automatic Computer and was developed in 1950. The concept of storing date and instructions inside the computer was introduced here. This allowed much faster operation since the computer had rapid access to both fata and instructions. The other advantage of storing instruction was that computer could do logical decision internally. The EDVAC was a binary serial computer with automatic addition subtraction multiplication, programmed division and automatic checking with an ultrasonic serial memory.
EDSAC : it stands for Electronic Delay storage Automatic Computer and was developed by M.V. Wilkes at Combridge University in 1949. The EDSAC is the first stored-program computer. The EDSAC performed computations in the three millisecond range. It performed arithmetic and logical operations without human intervention. The key to the success was in the stored instructions which it depended upon solely for its operation.
This Machine marked the beginning of the computer age.
UNIVAC-1: stands for universal Automatic computer and it was the first commercial computer developed by united states in 1951. The machine was 25 feet by 50 feet in length contained 5,600 tubes 18,000 crystal diodes, and 300 relays. It utilized serial circuitry, 2.25 MHz bit rate, and had an internal storage capacity 1,000 words or 12,000 characters.
The UNIVAC was used for general purpose computing with large amounts of input and output. The UNICAC was also the first computer to come equipped with a magnetic tape unit and was the first computer to use buffer memory.
Limitations of first Generation Computer
Followings are
the major drawbacks of first generation computers.
· 1. They used valves or vacuum tubes as their main electronic component.
· 2.They were large in size slow in processing and had less storage capacity.
· 3.They consumed lots of electricity and produced lots of heat.
· 4.Their computing capabilities were limited.
· 5.They were not so accurate and reliable.
· 6.They used machine level language for programming. They were very expensive.
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Second generation (1955-1964):
The second generation computer used transistors for CPU components and ferrite cores for main memory & magnetic disks for secondary memory. They used high-level languages such as FORTRAN(1956), ALGOL (1960), COBOL(1960-1961). Input Output (I/O) processor was included to control I/O operations.
Manufacturing cost was also very low. Thus the size of the computer got reduced considerably.
It is in the second generation that the concept of Central Processing Unit(CPU) Memory, Programming Language and Input and output units were developed. some of the second generation computers are IBM 1620 IBM 1401, CDC 3600.
· 1.Transistors were used instead of Vacuum tube.
· 2.Processing speed is faster than First Generation Computers(Micro Second)
· 3.Smaller in Size (51 square feet)
· 4.The input and output devices were faster.
Third Generation (1964-1977):
By the development of a small chip consisting of the capacity of the 300 transistors. These integrated Circuits(IC)s are popularly known as Chips.
A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. So it is quite obvious that the size of the computer got further reduced. Some of the computers developed during this period were IBM-360, ICL-1900, and VAX-750. Higher level language such as BASIC(Beginners All Purpose Symbolic Instruction Code) was developed during this period.
Computers of this generation were small in size, low cost, large, memory and processing speed is very high. Very soon ICs were replaced by LSI(Large Scale Integration), which consisted about 100 components.
And IC containing about 100 components is called LSI as In .
Features :
· They used integrated circuit(IC) chips in place of the transistors.
· Semi conductor memory devices were used.
· The size was greatly reduced the speed of processing was high, and they were more accurate and reliable.
· Large Scale Integration (LSI) and very large Scale Integration (VLSI) were also developed.
· The mini computers were introduced in this generation.
· They used high level language for programming.
Fourth Generation (1978- Present):
An IC containing about 100 components is called LSI(Large Scale Integration) and the one , which has more than 1000 such components is called as VLSI (Very Large Scale Integration)
It uses large scale integrated Circuits(LSIC) built on a single silicon chip called microprocessors. Dye to the development of microprocessor it is possible to place computer’s central processing unit(CPU) on single chip. These computers are called microcomputers.
Later very large scale integrated circuits(VLSIC) replaced LSICs. Thus the computer which was occupying a very large room in earlier days can now be placed on table. The personal computer(PC) that you see in your school is a Fourth generation Computer main memory used fast semiconductors chips up to 4 M bits size. Some of the Fourth generation computers are IBM PC, Apple-Macintosh, etc.
Hard disks were used as secondary memory. Keyboards, dot matrix printers etc. were developed. Operating system(OS) such as MS-DOS Unix, Apple’s Macintosh were Available. Object oriented language, C++ etc. were developed.
Features :
· 1.They used microprocessor(VLSI) as their main Switching element.
· 2.They are also called as micro computers or personal computers.
· 3.Their size varies from desktop to laptop or palmtop
· 4.They have very high speed of processing they are 100% accurate reliable, diligent and versatile.
· 5.They have very large storage capacity.
Fifth Generation(Present and Future):
5th generation computers use ULSI(ultra-large scale integration) chips Millions of transistors are placed in a single IC in ULSI chips.
64 bit microprocessors have been developed during this period. Memory chips and flash memory up to 1 GB. Hard disks up to 600 GB &optical disks up to 50 GB have been developed.
Fifth generation computing devices based on Artificial Intelligence are still in development though there are some applications such as voice recognition, that are being used today.
Artificial intelligence is the branch of computer science concerned with making computers behave like humans. The term was coined in 1956 by John McCarthy at the Massachusetts Institute of Technology. Artificial Intelligence includes.
Games Playing:
Programming Computers to play games such as chess and checkers
Expert Systems:
Programming computers to make decisions in real –life situations(for example, some expert system help doctors diagnose diseases based on symptoms)
Natural Language:
Programming computers to understand natural human languages
Neural networks:
Systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains
Robotics:
Programming computers to see and hear and react to other sensory stimuli
