PDP-7
The PDP-7, a member of the PDP series of computers, was introduced by Digital Equipment Corporation (DEC) in December 1964. Here are some key details about this historic machine:
Design and Architecture
- Processor: The PDP-7 used a 18-bit word length, with 16-bit instructions, which was an evolution from the earlier 12-bit PDP-4 and PDP-5. It featured a single-address architecture.
- Memory: It could support up to 64K words of core memory, although most configurations had far less due to cost considerations.
- I/O: The I/O operations were managed through a separate I/O Processor which allowed for direct memory access (DMA).
- Instruction Set: It had a simple instruction set that was later expanded for the PDP-11.
Significance
- Unix Development: One of the most significant aspects of the PDP-7 was its use by Ken Thompson and Dennis Ritchie at Bell Laboratories for the development of the Unix operating system. This system was initially written in Assembly Language for the PDP-7.
- Computing History: The PDP-7 played a pivotal role in the evolution of computer architecture and operating systems, influencing subsequent designs and software development practices.
Usage
- The PDP-7 was primarily used in research, educational institutions, and by businesses for scientific and engineering calculations.
- It was also popular in time-sharing environments due to its efficient memory usage and I/O handling capabilities.
Software
- Apart from Unix, the PDP-7 ran various assembly languages, FORTRAN compilers, and other specialized software tailored for its architecture.
End of Life
- The PDP-7 was discontinued in 1975, by which time more advanced models like the PDP-11 had taken over.
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