1st%20chapter

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1st chapter

• Rashedul Hasan

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1st Chapter.

• What Computer is
• -How does a Computer works
• -Characteristics of Computer
• -History of Computer
• -Computer Generation
• -Types of Computer

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What computer is

• The word Computer derives from Compute means
  To calculate
• Calculating device that can perform arithmetic
  operation at high speed.
• But to define a computer merely as a calculating
  device is to ignore over 80 of its Function.

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Data processor
Input
process
output
process
Data
Information
Store
Retrieve
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Data Information

• Data Data is Raw material used as input to Data
  processing.
• Information Information is processed data
  obtained as output of Data processing.

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Data Processing

• Processing in general terms, is a series of
  actions or operations that converts some input
  into useful output.
• Hence, Data processing is a series of actions or
  operations that converts data into output.
• Data processing transforms raw data into
  information.

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Results Of Process -ing In Human acceptable for
m
Input data From External Source
Input Data In Internal form
Process -ed Data In Internal form
CPU Memory
output Devices

• Input
• Devices

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What Computer is?

• Four basic functions of computers include
• Receive input
• Process information
• Produce output
• Store information

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Characteristics of Computer

• Automatic An automatic machine works by itself
  without human intervention. Computers are
  automatic machine as once started on a job, it
  carry out the job normally without human
  assistance until it is finished. We only need to
  instruct computer using coded instruction.

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• Speed a computer is very fast device. It can
  perform in a few seconds, the amount of work that
  a human being can do in an entire year.
• Computer can perform its tasks in a microsecond
  (10-6), nanosecond (10-9) and even in picoseconds
  (10-12),

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• Accuracy computers are very accurate. A computer
  can perform every calculation with the same
  accuracy over again and again.
• However errors can occur in computer due to
  incorrect input data or unreliable programs.
• Garbage in garbage out GIGO

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• Diligence Computer is free from monotony,
  tiredness and lack of concentration.
• It do not call for strike, movement for pay rise
  and does not create any political instability.

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• Versatility It is the most important
  characteristics of computer. One moment it is
  preparing results of an examination, next moment
  it is busy preparing salary sheet, and in between
  it may play your favorite songs.
• This is called multitasking ability.

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• Power of remembering People may forget many
  things over the time. But in case of computer, it
  can recall any amount of information stored in
  its memory.

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• No I.Q. Computer has no intelligence of its
  own. Its I.Q. is zero, at least until today. A
  computer cannot take its own decision. Only a
  user determines what tasks a computer will
  perform.

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• No feelings Computer has no emotion. Based on
  our feelings, taste, knowledge and experience we
  often make certain judgments in our day-to-day
  life whereas computer can not make such
  judgments.
• what is good what is bad.

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HOW DOES A COMPUTER WORK?

• The computer accepts input. Computer input is
  whatever is entered or fed into a computer
  system. Input can be supplied by a person (such
  as by using a keyboard) or by another computer or
  device (such as a diskette or CD-ROM). Some
  examples of input include the words and symbols
  in a document, numbers for a calculation,
  instructions for completing a process, pictures,
  and so on.

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HOW DOES A COMPUTER WORK?

• ? The computer performs useful operations,
  manipulating the data in many ways. This
  manipulation is called processing. Examples of
  processing include performing calculations,
  sorting lists of words or numbers, modifying
  documents and pictures according to user
  instructions, and drawing graphs. A computer
  processes data in the CPU.

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HOW DOES A COMPUTER WORK?

• ? The computer stores data. A computer must store
  data so that it is available for processing. Most
  computers have more than one location for storing
  data (the hard drive or C\, and the floppy drive
  or A\). The place where the computer stores the
  data depends on how the data is being used. The
  computer puts the data in one place while it is
  waiting to be processed and another place when it
  is not needed for immediate processing. The
  storage of data in the computer is called online
  storage while the storage of data on computer
  tapes, diskettes or CD-ROMs is called offline
  storage.

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HOW DOES A COMPUTER WORK?

• ? The computer produces output. Computer output
  is information that has been produced by a
  computer. Some examples of computer output
  include reports, documents, music, graphs, and
  pictures. Output can be in several different
  formats, such as paper, diskette, or on screen.

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Activity

• Describe, in terms of input, processing and
  data, the production of a letter using a
  computer. What happens first? What happens last?

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You could draw a simple flow chart that showed
the following

• The input for the letter is received from
  keyboarding, scanning or copying data from a disk
• The data are processed by the computer
• The data are stored in a storage device, such as
  a floppy disk, hard disk or magnetic tape
• The computer produces output in the form of a
  printed letter and an electronic version that may
  remain in the computer for future use or
  reference.

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History of Computer

• Pascal (1623-62) was the son of a tax collector
  and a mathematical genius. He designed the first
  mechanical calculator (Pascaline) based on gears.
  It performed addition and subtraction.
• Leibnitz (1646-1716) was a German mathematician
  and built the first calculator to do
  multiplication and division. It was not reliable
  due to accuracy of contemporary parts.

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History of Computer

• Babbage (1792-1872) was a British inventor who
  designed an analytical engine incorporating the
  ideas of a memory and card input/output for data
  and instructions. Never actually built.
• Babbage is largely remembered because of the work
  of Augusta Ada who was probably the first
  computer programmer.
• Many people refer him as a father of computer.
• Burroughs (1855-98) introduced the first
  commercially successful mechanical adding machine
  1,000,000 were sold by 1926.

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History of Computer

• Hollerith developed an electromechanical
  punched-card tabulator to tabulate the data for
  1890 U.S. census. Data was entered on punched
  cards and could be sorted according to the census
  requirements. The machine was powered by
  electricity. He formed the Tabulating Machine
  Company which became International Business
  Machines (IBM). IBM is currently the largest
  computer manufacturer, employing in excess of
  300,000 people.

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History of Computer

• Aiken (1900-73) a Harvard professor with the
  backing of IBM built the Harvard Mark I computer
  (51ft long) in 1944. It was based on relays
  (operate in milliseconds) as opposed to the use
  of gears. It required 3 seconds for a
  multiplication.

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History of Computer

• Eckert and Mauchly designed and built the ENIAC
  in 1946 for military computations. It used vacuum
  tubes (valves) which were completely electronic
  (operated in microseconds) as opposed to the
  relay which was electromechanical.
• It weighed 30 tons, used 18000 valves, and
  required 140 kwatts of power. It was 1000 times
  faster than the Mark I multiplying in 3
  milliseconds. ENIAC was a decimal machine and
  could not be programmed without altering its
  setup manually.

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History of Computer

• Atanasoff had built a specialised computer in
  1941 and was visited by Mauchly before the
  construction of the ENIAC. He sued Mauchly in a
  case which was decided in his favour in 1974!

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History of Computer

• Von Neumann was a scientific genius and was a
  consultant on the ENIAC project. He formulated
  plans with Mauchly and Eckert for a new computer
  (EDVAC) which was to store programs as well as
  data.  
• This is called the stored program concept and Von
  Neumann is credited with it. Almost all modern
  computers are based on this idea and are referred
  to as Von Neumann machines.  
• He also concluded that the binary system was more
  suitable for computers since switches have only
  two values. He went on to design his own computer
  at Princeton which was a general purpose machine.

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Examples of machines in the computer evolution

• 14th C. - Abacus - an instrument for performing
  calculations by sliding counters along rods or in
  grooves
• 17th C. - Slide rule - a manual device used for
  calculation that consists in its simple form of a
  ruler and a movable middle piece which are
  graduated with similar logarithmic scales
• 1642 - Pascaline--a mechanical calculator built
  by Blaise Pascal
• 1804 - Jacquard loom--a loom programmed with
  punched cards invented by Joseph Marie Jacquard
• 1850 - Difference Engine , Analytical
  Engine--Charles Babbage and Ada Byron Babbage's
  description, in 1837, of the Analytical Engine, a
  mechanical digital computer anticipated virtually
  every aspect of present-day computers.

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Examples of machines in the computer evolution

• 1939 -1942 - Atanasoff Berry Computer - built at
  Iowa State by Prof. John V. Atanasoff and
  graduate student Clifford Berry. Represented
  several "firsts" in computing, including a binary
  system of of arithmetic, parallel processing,
  regenerative memory, separation of memory and
  computing functions, and more. Weighed 750 lbs.
  and had a memory storage of 3,000 bits (0.4K).
  Recorded numbers by scorching marks into cards as
  it worked through a problem.
• 1946 - ENIAC--World's first electronic, large
  scale, general-purpose computer, built by Mauchly
  and Eckert, and activated at the University of
  Pennsylvania in 1946. ENIAC recreated on a modern
  computer chip. The ENIAC is a 30-ton machine,
  filled with 19,000 vacuum tubes, 6000 switches,
  and could add 5,000 numbers in a second, a
  remarkable accomplishment at the time. A
  reprogrammable machine, the ENIAC performed
  initial calculations for the H-bomb.
• 1940s - Colossus - Alan Turing's vacuum tube
  computing machines broke Hitler's Enigma codes.

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Examples of machines in the computer evolution

• 1950s -1960s - UNIVAC - "punch card technology"
  The first commercially-successful computer,
  introduced in 1951 by Remington Rand. Over 40
  systems were sold. Its memory was made of
  mercury-filled acoustic delay lines that held
  1,000 12-digit numbers. It used magnetic tapes
  that stored 1MB of data at a density of 128 cpi.
  UNIVAC became synonymous with computer (for a
  while).

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Evolution of Computing
No Computers
PCs introduced!
1960s
2001
1950
mid- 1970s
Very expensive computers for large companies.
Computer professionals ran the show.
Powerful PCs on every desktop. Explosion of
applications.
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Computer Generation

• Generation in computer talk is step in
  technology.
• It is used to distinguish between various
  hardware technologies.
• Totally 4 computer generations known till today.

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COMPUTER GENERATIONS

• 1. VACUUM TUBES 1946-1959

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VACUUM TUBES
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Tubes from a 1950s computer.
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VACUUM TUBES

• a vacuum tube is a device used to amplify,
  switch, otherwise modify, or create an electrical
  signal by controlling the movement of electrons
  in a low-pressure space.

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Characteristics of 1st Generation computer

• Too big in size.
• Used vacuum tube.
• Power consumption of these computers was very
  high.
• Magnetic drums were developed to store
  information and tapes were also developed for
  secondary storage.
• Power consumption of these computers was very
  high.
• Limited commercial use. Mainly used for
  scientific computations.
• Commercial production was difficult and costly.

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COMPUTER GENERATIONS

• 1. VACUUM TUBES 1946-1959
• 2. TRANSISTORS 1957-1963

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Transistors
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Transistors
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TRANSISTORS

• a transistor is a semiconductor device commonly
  used to amplify or switch electronic signals.
• The transistor is the fundamental building block
  of modern electronic devices.

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Comparison with vacuum tubesAdvantages

• Small size and minimal weight, allowing the
  development of miniaturized electronic devices.
• Highly automated manufacturing processes,
  resulting in low per-unit cost.
• Lower possible operating voltages, making
  transistors suitable for small, battery-powered
  applications.
• No warm-up period for cathode heaters required
  after power application.
• greater energy efficiency.
• Higher reliable.
• Extremely long life. Some transistorized devices
  produced more than 30 years ago are still in
  service.

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Characteristics of 2nd Generation computer

• Faster, smaller and more reliable.
• Smaller in size than first generation computer
  and were more reliable and less prone to hardware
  failure.
• They were more than ten times faster than the
  first generation computer.
• Consumed almost one-tenth the power consumed by a
  tube.
• Were less expensive.
• Commercial production was still difficult and
  costly.
• Another major feature of the second generation
  was the use of high-level programming languages
  such as Fortran and Cobol. These revolutionised
  the development of software for computers.

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COMPUTER GENERATIONS

• 1. VACUUM TUBES 1946-1959
• 2. TRANSISTORS 1957-1963
• 3. INTEGRATED CIRCUITS 1964-1979

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INTEGRATED CIRCUITS
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INTEGRATED CIRCUITS

• an integrated circuit (also known as IC,
  microcircuit, microchip, silicon chip, or chip)
  is a miniaturized electronic circuit (consisting
  mainly of semiconductor devices) that has been
  manufactured in the surface of a thin plate of
  semiconductor material.

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Generation of I.C.

• The first integrated circuits contained only a
  few transistors. Called "Small-Scale Integration"
  (SSI), they used circuits containing transistors
  numbering in the tens.
• The next generation in the development of
  integrated circuits, taken in the late 1960s,
  introduced devices which contained hundreds of
  transistors on each chip, called "Medium-Scale
  Integration" (MSI).

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• They were more powerful then 2nd generation
  computer. They were capable of performing 1
  million instruction per second.
• They were smaller then 2nd generation computer
  requiring smaller place.
• They consumed less power dissipated less heat.
• Was suitable for commercial uses.
• They were easier to upgrade.

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COMPUTER GENERATIONS

• 1. VACUUM TUBES 1946-1959
• 2. TRANSISTORS 1957-1963
• 3. INTEGRATED CIRCUITS 1964-1979
• 4. VERY LARGE-SCALE INTEGRATED (VLSI) CIRCUITS
  1980- PRESENT

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Very Large-Scale Integration

• The final step in the development process,
  starting in the 1980s and continuing through the
  present, was "Very Large-Scale Integration"
  (VLSI). This could be said to start with hundreds
  of thousands of transistors in the early 1980s,
  and continues beyond several billion transistors
  as of 2007.

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COMPUTER GENERATIONS

• General purpose machine. Suitable for scientific
  commercial uses.
• Cheaper and very powerful.
• Much smaller and handy. (such as Laptop)
• Consume less power and less prone to hardware
  failure than 3rd generation computers.
• More reliable.
• Faster and larger storage.
• More user friendly interface with multi media
  features.
• Graphical user interface enables new user to
  quickly learn how to use computer.
• Easier to produce commercially.
• Secondary storage has also evolved at fantastic
  rates with storage devices holding gigabytes
  (1000Mb 1 Gb) of data.

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In short
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Types of Computer

• SUPERCOMPUTER
• MAINFRAME
• MINICOMPUTER
• MICROCOMPUTER
• LAPTOPS SMALLER

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SUPERCOMPUTERTERAFLOP TRILLION
CALCULATIONS/SECOND

• An extremely fast computer that can perform
  hundreds of millions of instructions per second.
• Supercomputers are very expensive and are
  employed for specialized applications that
  require immense amounts of mathematical
  calculations. For example, weather forecasting
  requires a supercomputer. Other uses of
  supercomputers include fluid dynamic
  calculations, nuclear energy research, and
  petroleum exploration.

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SUPERCOMPUTER

• E.g.- CRAY Research- CRAY-1 CRAY-2,
• Fujitsu (VP2000),
• Hitachi (S820),
• NEC (SX20),
• PARAM 10000 by C-DAC.

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General Use of Super Computer

• Petroleum industry - to analyze volumes of
  seismic data which are gathered during oil
  seeking explorations to identify areas where
  there is possibility of getting petroleum
  products inside the earth
• Aerospace industry - to simulate airflow around
  an aircraft at different speeds and altitude.
  This helps in producing an effective aerodynamic
  design for superior performance
• Automobile industry to do crash simulation of
  the design of an automobile before it is released
  for manufacturing for better automobile design
• Structural mechanics to solve complex
  structural engineering problems to ensure safety,
  reliability and cost effectiveness. Eg. Designer
  of a large bridge has to ensure that the bridge
  must be proper in various atmospheric conditions
  and pressures from wind, velocity etc and under
  load conditions. ?Meteorological centers use
  super computers for weather forecasting
• Biomedical research atomic nuclear and plasma
  analysis to study the structure of viruses such
  as that causing AIDS
• Other Use For weapons research and development,
  sending rockets to space etc

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SUPERCOMPUTER

• Teraflop Trillion calculations/second
• Highly sophisticated
• CPU speed 100 MIPS, Equivalent to 4000 computers
• Complex computations
• Fastest CPUS
• Large simulations High precision
• State-of-the-art components
• Expensive

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MAINFRAME
MIPS Millions of Instructions per second

• A powerful multi-user computer capable of
  supporting many hundreds or thousands of users
  simultaneously.
• mainframes are just below supercomputers.
• The chief difference between a supercomputer and
  a mainframe is that a supercomputer channels all
  its power into executing a few programs as fast
  as possible, whereas a mainframe uses its power
  to execute many programs concurrently.
• E.g.- IBM 3000 series, Burroughs B7900, Univac
  1180, DEC

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MAINFRAME
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MAINFRAME
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• Mainframe computers are large-sized, powerful
  multi-user computers that can support concurrent
  programs. That means, they can perform different
  actions or processes at the same time.
  Mainframe computers can be used by as many as
  hundreds or thousands of users at the same time.
  Large organizations may use a mainframe computer
  to execute large-scale processes such as
  processing the organizations payroll.

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General Use of Mainframe Computer

• Used to process large amount of data at very
  high speed such as in the case of Banks/
  Insurance Companies/ Hospitals/ Railway etc.
  which need online processing of large number of
  transactions and requires massive data storage
  and processing capabilities
• Used as controlling nodes in WANs (Wide Area
  Networks)
• Used to mange large centralized databases

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MAINFRAME

• MIPS millions of instructions per second
• Largest enterprise computer
• Able to process large amount of data at very high
  speed
• Supports multi-user facility
• Supports many I/O and auxiliary storage devices
• 5o megabytes to over one gigabyte ram
• Commercial, scientific, military applications
• Massive data
• Complicated computations

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MINICOMPUTER

• A multi-user computer capable of supporting from
  10 to hundreds of users simultaneously.
• E.g.- Digital Equipments PDP 11/45 and VAX 11)
• Middle-range
• 10 megabytes to over one gigabyte ram
• Universities, factories, labs
• Used as front-end processor for mainframe. Can
  also communicate with main frames
• Perform better than micros
• Designed to support more than one user at a time
• Posses large storage capacities and operates at
  higher speed

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• Mini-computers are mid-sized multi-processing
  computers. Again, they can perform several
  actions at the same time and can support from 4
  to 200 users simultaneously.
• In recent years the distinction between
  mini-computers and small mainframes has become
  blurred. Often the distinction depends upon how
  the manufacturer wants to market its machines.
  Organizations may use a mini-computer for such
  tasks as managing the information in a small
  financial system or maintaining a small database
  of information about registrations or
  applications.

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MICROCOMPUTER

• A small, single-user computer based on a
  microprocessor. In addition to the
  microprocessor, a personal computer has a
  keyboard for entering data, a monitor for
  displaying information, and a storage device for
  saving data.
• E.g.- IBM PC, PS/2 and Apple Macintosh
• Microcomputer is generally used in the field of
  desktop publishing, accounting, statistical
  analysis, graphic designing, investment analysis,
  project management, teaching, entertainment etc

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MICROCOMPUTER

• Desktop or portable
• They are designed to be used by only one person
  at a time
• A microcomputer uses a microprocessor as its
  central processing unit. Microcomputers are tiny
  computers that can vary in size from a single
  chip to the size of a desktop model
• Personal or business computers
• Affordable
• Many available components
• Can be networked

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• Personal computers (PCs), also called
  microcomputers, are the most popular type of
  computer in use today. The PC is a small-sized,
  relatively inexpensive computer designed for an
  individual user. Today, the world of PCs is
  basically divided between IBM-compatible and
  Macintosh-compatible machines, named after the
  two computer manufacturers. Computers may be
  called desktop computers, which stay on the
  desk, or laptop computers, which are
  lightweight and portable. Organizations and
  individuals use PCs for a wide range of tasks,
  including word processing, accounting, desktop
  publishing, preparation and delivery of
  presentations, organization of spreadsheets and
  database management. Entry-level PCs are much
  more powerful than a few years ago, and today
  there is little distinction between PCs and
  workstations.

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LAPTOPS SMALLER

• PERSONAL COMPUTERS (PC) The name PC was given by
  the IBM for its microcomputers. PCs are used for
  word processing, spreadsheet calculations,
  database management etc.
• LAPTOP (OR NOTEBOOK) Briefcase type package,
  very portable, can be inexpensive, can connect to
  other computers or networks
• HAND-HELD (OR PALMTOP) Sub-miniature, wireless
  computer. Growing in sophistication and
  connectivity

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Activity

• If you have computer in your home find out the
  type or types. Are they mainframe computers,
  mini-computers, workstations or personal
  computers? What processes or actions are the
  computers used for? Write a brief description of
  the types of computers in place and their main
  uses. If you have more than one type of computer,
  find out why? What different tasks are the
  different computers intended to do?
• If you have not any computer in your home, try to
  contact a colleague or friend who has a computer
  and ask him or her what type he or she has and
  what primary functions it is used for.