Computer History
Computer system as mulitlevel machine #
- Level 5
- Problem oriented language level (C++/…)
- Level 4
- Assembly language level
- Level 3
- Operating system machine level (syscalls)
- Level 2
- Instruction set architectures
- Level 1
- Microarchitecture level
- Level 0
- Digital logic level
Evolution #
Micoprogramming #
Microcode is a layer of hardware-level instructions that implement higher-level machine code instructions or internal finite-state machine sequencing in many digital processing elements.
-> So basically the processor has a few internal instructions which it uses to implement the machine code instructions of the ISA.
- Invented 1951 by Maurice Wilkes
- Simplified hardware
Single user #
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computers could only be used by one user
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program on punch cards (in some language)
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compiler is also set of cards
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feed compiler into machine
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feed program into machine
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compiler will compile the program
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output compiled program as punch cards
Operating System wars #
- 1960s
- Operating system was kept in memory
- Maches did not need an “Operator” any more
Timesharing Machines #
- Allow multiple users on the same machine at the same time
- 1960s at MIT
Computer Generations #
- Generation 0
- 1945 -> Mechanical computers
- Generation 1
- 1955 -> Vacuum Tubes
- Generation 2
- 1965 -> Transistors
- Generation 3
- 1980 -> Integrated circuits
- Generation 4
- Very large scale integration
- Generation 5
- Ubiquitous computing