classification of...
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CLASSIFICATION OF COMPUTERS
According to function/logic use:
1. Analog computer
2. Digital computer
3. Hybrid Computer
1. ANALOG COMPUTERS are that in which data varies continuously i.e. the
movement of data is continuous.
REPRESENTED BY: series of waves
OR
An analog computer is a form of computer that uses the continuously changeable
aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to
Model the Problem being solved.
Polish Analog computer:
USED FOR
Measuring temperature, pressure, etc
Communication
Broadcast transmission
EXAMPLE
Automobile Speedometer, Voltmeter, etc
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2. DIGITAL COMPUTERS:
Digital Computers are those computers in which data flows in discrete form.
REPRESENTED BY: Pulses, two series i.e. 0s & 1s
OR
Digital computer, any of a class of devices capable of solving problems by processing
information in discrete form. It operates on data, including magnitudes, letters, and
symbols, that are expressed in binary form—i.e., using only the two digits 0 and 1.
OR
Computer that stores data in terms of digits (numbers) and proceeds in discrete steps from
one state to the next. The states of a digital computer typically involve binary digits
which may take the form of the presence or absence of magnetic markers in a storage
medium, on-off switches or relays. In digital computers, even letters, words and whole
texts are represented digitally.
USED FOR
Mathematical calculations
Compare values
Storing the result
EXAMPLE
Digital watch, Education system, business purpose
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3. HYBRID COMPUTERS
Hybrid Computers are combination of both analog computer and digital computer
MEASURES: both continuous and discrete form of data
OR
Hybrid computers are computers that exhibit features of analog computers and digital
computers.
OR
Computers that exhibit features of analog computers and digital computers. The digital
component normally serves as the controller and provides logical operations, while the
analog component normally serves as a solver of differential equations.
EXAMPLE
STD/PCO phone, where one communicate with a person using analog computer & the
rate as charges and pulse rate is measured in forms of digit or A petrol pump contains a
processor that converts fuel flow measurements into quantity and price values.
In hospital Intensive Care Unit (ICU), an analog device is used which measures patient's
blood pressure, heart beat or ECG, and temperature etc, which are then converted and
displayed in the form of digits.
Hybrid Computers:
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Digital Computer Classification according to purpose:
General Purpose Computer
Special Purpose Computer
GENERAL PURPOSE COMPUTER:
These are designed to perform the variety of jobs or applications for this reason; they are
less efficient than special purpose computers.
EXAMPLE
Banking, Sales Analysis, PCs, etc
SPECIAL PURPOSE COMPUTER:
These are designed to meet the needs of some special application. They are designed to
perform a single job. So they execute a task quickly and more efficiently. Program and
instructions are stored permanently in them.
EXAMPLE:
Weapon designing
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Digital Computer Classification according to sizes:
1. Super Computer
2. Mainframe Computer
3. Mini Computer
4. Micro Computer
5. Desktop Computer
6. Pocket Computer
1. SUPER COMPUTER:
The fastest type of computer, Supercomputers are very expensive and are employed for
specialized applications that require immense amounts of mathematical calculations. For
example, weather forecasting requires a supercomputer.
PURPOSE: Special purpose computers handle mostly complex scientific, statistical
applications or programs.
KEY FEATURES
High technology
High capacity memory i.e. 8.4 million
Computes data processing in short time
Highly sophisticated technology
Cost varies from 1 million to 5 million
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EXAMPLE:
1. Titan:-
The fastest supercomputer in the world is used to study alternative energy resources and
climate change simulations in a global level.
2. Sequoia:-
This one’s a life saver. USA doesn’t have to actually conduct nuclear tests anymore,
Sequoia simulates them. This one makes sure that the nuclear weapons are ready for
action any time of the day.
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3. IBM Mira:-
Mira by IBM, simulates the evolution of the Universe. It also runs the climate change
scenarios and helps in research of more efficient car batteries.
Super computer in India:
• India’s first super computer is PARAM yuva II
• I Data Plex DX360M4
• Cluster Platform 3000 BL460c Gen8
• SAGA - Z24XX/SL390s Cluster
• EKA
DRAWBACK
Operating Supercomputer requires highly qualified staff.
Experts were required for such computer engineering.
They are sensitive to temperature, humidity, dust, etc.
Non portability & large size
2. MAINFRAME COMPUTERS:
The term referred to the large cabinets that housed the central processing unit and main
memory of early computers. Modern mainframes can run multiple different instances of
operating systems at the same time.
KEY FEATURES
Smaller size than super computer
Large memory capacity
Allows networking of up to 100 terminals
Cost varies from 5-20 lacs.
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EXAMPLE
1. IBM System 3:
2. AS-400:
3. PDP-370, IBM 40
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DISADVANTAGES
Experts and highly qualified professionals were required to operate it
Sophisticated technology required for manufacturing & assembling the computer
3. MINI COMPUTER:
A minicomputer, or colloquially mini, is a class of smaller computers that evolved in the
mid-1960s. They use of transistors and core memory technologies, minimal instructions
sets and less expensive peripherals such as the ubiquitous Teletype Model 33 ASR.
KEY FEATURES
Higher processing speed than lowest category computer but slower than super computer
& Mainframe computer
Portable computers because of smaller size
Memory capacity RAM is up to 128 MB
Secondary Memory store 40 GB
Costs around Rs 50 thousand to 90 thousand
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EXAMPLE:
1. The first successful Western minicomputer was Digital Equipment Corporation's 12-bit
PDP-8, which was built using discrete transistors and cost from US$16,000 upwards
when launched in 1964.
2. The 7400 series of TTL integrated circuits started appearing in minicomputers.
3. PDP-11 and PDP-45 etc.
DISADVANTAGES
Cannot connect all hardware devices
Cannot execute all languages and software
4. MICRO COMPUTER:
A microcomputer is a small, computer with a microprocessor as its central processing unit
(CPU).Microcomputers became popular in the 1970s and 80s with the advent of increasingly
powerful microprocessors.
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KEY FEATURES
Smaller than Mini Computer
High speed computer but slower than mini computer
Costs around Rs 30000 to 60000
Portable
RAM requires 64 MB to 128 MB
Limited languages FORTRAN, Basic, COBOL, Pascal can be executed
EXAMPLE
1. ECD Micro mind:
2. Data point 2200:
3. Uptron, HCL, PCL, Wipro, PCs, HP, PC-AT, PC-XT
DRAWBACKS
Limited Hardware devices can be connected
Experts were required
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5. DESKTOP COMPUTERS:
A Desktop computer is a personal computer in a form intended for regular use at a
single location, as opposed to a mobile laptop or portable computer.
PURPOSE: Education system and small scale industry
CALLED: HOME or Briefcase Computers
KEY FEATURES
Portable
High speed processing processor varies from 80286 to 80586
Requires RAM from 16 MB to 64 MB
Internet facility for communication
Costs around Rs 30,000 to Rs 60,000
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EXAMPLE
HCL, PCL, Wipro, COMPAQ, HP, LEO, SAMSUNG, etc
DISADVANTAGES
Execute limited software and languages related to windows based
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6. POCKET COMPUTER
KEY FEATURES
Small in size
Portable like a digital diary
Requires RAM maximum up to 1GB
Disk capacity is 80 GB
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DISADVANTAGE
Execute limited Software