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Types of General Purpose Computers
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Mainframe
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- 1950's
- 1947 IBM 700 series (vacuum tubes), later 7000 series (transistors)
- still in use today, mostly legacy applications
Attributes
* large transactional power
* large input/output (I/O) capability
* virtualisation (can run multiple OS's)
* high stability and reliability (restarted once a decade)
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Supercomputer
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- 1960's
Attributes
* massive processing power --> arithmetic calculations
* parallelism
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Mini computer
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- Mid 1960's to mid 1980's
- Took advantage of the cost and size savings of transistors (later models used microprocessors).
- 10 to 20 thousand dollars US.
Attributes
* Native interpreters --> allowed for high level languages --> easier to program
* Significantly cheaper and smaller.
* Lower computational and transactional capability, but the cost allowed for wider application.
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Microcomputer
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- Introduced in the 1970's.
e.g. Altair 8800 that used Intel 8080 (clock 2MHz, ~4500 transistors)
- Became popular in the 1980's.
e.g. IBM XT, Apple II, Commodore 64.
Attributes
* Microprocessor (much cheaper to produce, much higher transistor density)
* Today have billions of transistors
