PDP-7

PDP-7
A PDP-7 in Oslo, Norway
Manufacturer:	Digital Equipment Corporation
Year Introduced:	1965
Form Factor:	minicomputer
Word Size:	18 bits
Logic Type:	PNP Transistor FLIP CHIPs
Memory Speed:	1.75 μsec
Physical Address Size:	15 bits (32K words)
Virtual Address Size:	13 bits (direct), 15 bits (extended)
Operating System:	DECSYS-7
Predecessor(s):	PDP-4
Successor(s):	PDP-9
Price:	US$72K

The PDP-7 is a minicomputer produced by DEC. Introduced in 1965, the first to use their Flip-Chip® technology, with a low cost, it was cheap but powerful. The PDP-7 was the third of Digital's 18-bit machines, with essentially the same instruction set and architecture as the predecessor PDP-4 and successor PDP-9. It was the first wire-wrapped PDP.

In 1969, Ken Thompson wrote the first UNIX system in assembly language on a PDP-7, then named Unics as a somewhat treacherous pun on Multics, as the operating system for Space Travel, a game which required graphics to depict the motion of the planets. A PDP-7 was also the development system used during the development of MUMPS at MGH in Boston a few years earlier.

There are a few remaining PDP-7's still in operable condition, along with one under restoration in Oslo, Norway.

Emulation

The PDP-7 can be emulated with SIMH. DECSys and some other software is available and can run on the emulator.

External links

• "The famous PDP-7 comes to the rescue" (Bell Labs' Unix history)
• http://research.microsoft.com/~gbell/Digital/timeline/1964-3.htm PDP-7 entry from Year 1964 in the DIGITAL Computing Timeline
• http://heim.ifi.uio.no/~toresbe/dec PDP-7 restoration project located in Oslo, Norway