Superior College Okara

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