Five Generations of Computer

Computer is an electronic device,operating under the control of instructions stored in its own memory,that can accept data,process the data according to specific rules,produce information and store the information for future

5 GENERATIONS OF COMPUTER

•   First Generation (1946-1954)

The first computer systems used vacuum tubes for circuitry and magnetic drum for memory, and were often enormous, taking up entire rooms.It is also very expensive.The Vacuum tube was developed by Lee DeForest in 1908.It consumes a lot of power.The first generation stored information in the form of propagating sound waves.They were large in size, slow in processing and had less storage capacity.They consumed lots of electricity and produced lots of heat. Their computing capabilities were limited. They were not so accurate and reliable.They used machine level language for programming.Example of first generation computer is ENIAC (Electronic Numerical Integrator and Calculator).

It  was the first general-purpose electronic computer built in 1946 at University of Pennsylvania, USA by John Mauchly and J. Presper Eckert.ENIAC contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints. It weighed more than 30 short tons (27 t), was roughly 8 by 3 by 100 feet (2.4 m × 0.9 m × 30 m), took up 1800 square feet (167 m2), and consumed 150 kW of power. Input was possible from an IBM card reader, and an IBM card punchwas used for output.It could store only limited or small amount of information.

•   Second Generation (1955-1964)

The second-generation computer used transistors for CPU components & ferrite cores for main memory & magnetic disks for secondary memory.The transistor was invented at Bell Labs in 1947 but did not see widespread use in computers until the late 1950s. A transistors is much smaller in the size than that of a vaccum tube.Transistors have higher operating speed. They have no filament and require no heating. 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.Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words.The programming languages such as COBOL, FORTRAN were developed during this period.Example of second generation are IBM 1400 and 7000 Series, Control Data 3600.

•   Third Generation (1964-1977)

 By the development of a small chip consisting of the capacity of the 300 transistors. These ICs 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, IBM-370, 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. An IC containing about 100 components is called LSI. 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, 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. Example of third generation are IBM 360, IBM 370 etc. 

•   Fourth Generation 

 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. Due 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 a 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. Hard disks were used as secondary memory. Keyboards, dot matrix printers etc. were developed. OS-such as MS-DOS, UNIX, Apple’s Macintosh were available. Object oriented language, C++ etc were developed. 

 They used Microprocessor (VLSI) as their main switching element.  They are also called as micro computers or personal computers.  Their size varies from desktop to laptop or palmtop. They have very high speed of processing; they are 100% accurate, reliable,   diligent and versatile. They have very large storage capacity.

Example of fourth generation are IBM PC, Apple-Macintosh

• Fifth Generation (1991-continued)

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. Data flow & EPIC architecture of these processors have been developed. RISC & CISC, both types of designs are used in modern processors. 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 digital computer will be Artificial intelligence.

Reference : Vangie B. (2010, January 22) The five generations of computers. Retrieved from https://www.webopedia.com/DidYouKnow/Hardware_Software/FiveGenerations.asp