The document summarizes the five generations of computers from 1945 to the present. The first generation used vacuum tubes and were bulky, power-hungry machines used mainly for scientific computations. The second generation saw the introduction of transistors, making computers smaller and more reliable. The third generation saw the rise of integrated circuits and memory became semiconductor-based. The fourth generation began using microprocessors and saw widespread adoption of personal computers. The fifth generation began in 1989 and is characterized by advancements in parallel processing, portable devices, networking and artificial intelligence.

1.  Write About The Generations Of Computers

2. I Generations : 1945 – 55
II Generation : 1955 – 65
III Generation : 1965 – 75
IV Generation : 1975 – 89
V Generation : 1989 to present
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3.  Vacuum tubes were used – basic arithmetic operations took few milliseconds ƒ
 Bulky ƒ
 Consume more power with limited performance ƒ
 High cost ƒ
 Uses assembly language – to prepare programs. These were translated into
machine level language for execution. ƒ
 Mercury delay line memories and Electrostatic memories were used ƒ
 Fixed point arithmetic was used ƒ
 100 to 1000 fold increase in speed relative to the earlier mechanical and relay
based electromechanical technology ƒ
 Punched cards and paper tape were invented to feed programs and data and
to get results. ƒ
 Magnetic tape / magnetic drum were used as secondary memory ƒMainly used
for scientific computations.
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4.  Vacuum tube technology
 Unreliable
 Supported Machine language only
 Very costly
 Generate lot of heat
 Slow Input/Output device
 Huge size
 Need of A.C.
 Non portable
 Consumed lot of electricity
Some computer of this generation were:
 ENIAC
 EDVAC
 UNIVAC
 IBM-701
 IBM-650
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5.  Transistors were used in place of vacuum tubes. (invented at AT&T Bell lab in 1947) ƒ
 Small in size ƒ
 Lesser power consumption and better performance
 Lower cost ƒ
 Magnetic ferrite core memories were used as main memory which is a random-access
nonvolatile memory ƒ
 Magnetic tapes and magnetic disks were used as secondary memory
 Hardware for floating point arithmetic operations was developed. ƒ
 Index registers were introduced which increased flexibility of programming. ƒ
 High level languages such as FORTRAN, COBOL etc were used - Compilers were
developed to translate the high-level program into corresponding assembly language
program which was then translated into machine language. ƒ
 Separate input-output processors were developed that could operate in parallel with
CPU. ƒ
 Punched cards continued during this period also. ƒ
 1000 fold increase in speed. ƒ
 Increasingly used in business, industry and commercial organizations for preparation
of payroll, inventory control, marketing, production planning, research, scientific &
engineering analysis and design etc.
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6.  Use of transistors
 Reliable as compared to First generation computers
 Smaller size as compared to First generation computers
 Generate less heat as compared to First generation computers
 Consumed less electricity as compared to First generation computers
 Faster than first generation computers
 Still very costly
 A.C. needed
 Support machine and assembly languages
Some computer of this generation were:
 IBM 1620
 IBM 7094
 CDC 1604
 CDC 3600
 UNIVAC 1108
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7.  ICs were used ƒ
 Small Scale Integration and Medium Scale Integration technology were
implemented in CPU, I/O processors etc.
 ƒSmaller & better performance ƒ
 Comparatively lesser cost ƒ
 Faster processors
 ƒIn the beginning magnetic core memories were used. Later they were
replaced by semiconductor memories (RAM & ROM) ƒ
 Introduced microprogramming ƒ
 Microprogramming, parallel processing (pipelining, multiprocessor system
etc), multiprogramming, multi-user system (time shared system) etc were
introduced. ƒ
 Operating system software were introduced (efficient sharing of a
computer system by several user programs) ƒ
 Cache and virtual memories were introduced (Cache memory makes the
main memory appear faster than it really is. Virtual memory makes it
appear larger) ƒ
 High level languages were standardized by ANSI e.g. ANSI FORTRAN, ANSI
COBOL etc ƒ
 Database management, multi-user application, online systems like closed
loop process control, airline reservation, interactive query systems,
automatic industrial control etc emerged during this period.
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8.  IC used
 More reliable
 Smaller size
 Generate less heat
 Faster
 Lesser maintenance
 Still costly
 A.C needed
 Consumed lesser electricity
 Support high level language
Some computer of this generation were:
 IBM-360 series
 Honeywell-6000 series
 PDP(Personal Data Processor)
 IBM-370/168
 TDC-316
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9.  Microprocessors were introduced as CPU– Complete processors and large
section of main memory could be implemented in a single chip ƒ
 Tens of thousands of transistors can be placed in a single chip (VLSI design
implemented) ƒ
 CRT screen, laser & ink jet printers, scanners etc were developed. ƒ
 Semiconductor memory chips were used as the main memory. ƒ
 Secondary memory was composed of hard disks – Floppy disks & magnetic
tapes were used for backup memory ƒ
 Parallelism, pipelining cache memory and virtual memory were applied in a
better way ƒ
 LAN and WANS were developed (where desktop work stations
interconnected)
 ƒIntroduced C language and Unix OS ƒ
 Introduced Graphical User Interface
 Less power consumption ƒ
 High performance, lower cost and very compact ƒ
 Much increase in the speed of operation
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10.  VLSI technology used
 Very cheap
 Portable and reliable
 Use of PC's
 Very small size
 Pipeline processing
 No A.C. needed
 Concept of internet was introduced
 Great developments in the fields of networks
 Computers became easily available
Some computer of this generation were:
 DEC 10
 STAR 1000
 PDP 11
 CRAY-1(Super Computer)
 CRAY-X-MP(Super Computer)
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11.  Generation number beyond IV, have been used occasionally to describe some
current computer system that have a dominant organizational or application
driven feature. ƒ
 Computers based on artificial intelligence are available ƒ
 Computers use extensive parallel processing, multiple pipelines, multiple
processors etc ƒ
 Massive parallel machines and extensively distributed system connected by
communication networks fall in this category. ƒ
 Introduced ULSI (Ultra Large Scale Integration) technology – Intel’s Pentium 4
microprocessor contains 55 million transistors millions of components on a
single IC chip. ƒ
 Superscalar processors, Vector processors, SIMD processors, 32 bit micro
controllers and embedded processors, Digital Signal Processors (DSP) etc
have been developed. ƒ
 Memory chips up to 1 GB, hard disk drives up to 180 GB and optical disks up
to 27 GB are available (still the capacity is increasing) ƒ
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12.  Object oriented language like JAVA suitable for internet programming
has been developed. ƒ
 Portable note book computers introduced ƒ
 Storage technology advanced – large main memory and disk storage
available ƒ
 Introduced World Wide Web. (and other existing applications like e-
mail, e Commerce, Virtual libraries/Classrooms, multimedia
applications etc.) ƒ
 New operating systems developed – Windows 95/98/XP/…, LINUX,
etc. ƒ
 Got hot pluggable features – which enable a failed component to be
replaced with a new one without the need to shutdown the system,
allowing the uptime of the system to be very high. ƒ
 The recent development in the application of internet is the Grid
technology which is still in its upcoming stage. ƒ
 Quantum mechanism and nanotechnology will radically change the
phase of computers
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13.  ULSI technology
 Development of true artificial intelligence
 Development of Natural language processing
 Advancement in Parallel Processing
 Advancement in Superconductor technology
 More user friendly interfaces with multimedia features
 Availability of very powerful and compact computers at
cheaper rates
Some computer types of this generation are:
 Desktop
 Laptop
 NoteBook
 UltraBook MOHSIN RAZA-ROLL #15