PDP-11

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The PDP-11 is a series of computers introduced in 1970 by Digital Equipment Corporation (DEC).
A loaded PDP-11/23 PLUS

The machine word size was 16 bits. For more information about the architecture itself, see PDP-11 architecture.

It could run a variety of operating systems. Many were produced by DEC themselves, but several were produced by third-parties. Often DEC would purchase or rebrand this OS and resell it as their own product. For example, UNIX sold as Ultrix by DEC.

Operatingn Systems

Unix based Operating Systems

This was the first shipping unix distro by the CSRG. It included a few fixes, and a bunch of the BSD utilities. This released was based on Unix System 6.

This version was a port of the 4.3 feature set to the PDP-11. Although considered impossible by many, it accomplished this by using overlays for portions of the kernel, and exe's to allow for programs larger then 64kb.

This version is still supported, and if you really felt the need to load a Unix for use on a PDP-11 this would be the best fit. It has support for TCP/IP, large memory space and is the best UNIX experence you are going to get on a 16bit mini.

Other OS's

PDP-11 Models and notes

Model Introduced Bus Type Addressing Notes Speed (VUPS)
11/20 1970 UNIBUS 16-bit
11/05 1972 UNIBUS 16-bit
11/10 1972 UNIBUS 16-bit
11/15 1972 UNIBUS 16-bit OEM model
11/40 1973 UNIBUS 18-bit
11/45 1973 UNIBUS 18-bit core memory
11/50 1975 UNIBUS 18-bit MOS memory
11/70 1975 UNIBUS 22-bit 0.6
11/03 1975 QBUS 16-bit first QBUS model, first F-11 0.5
11/34 1976 UNIBUS 18-bit 0.21
11/04 1976 UNIBUS 16-bit 0.11
11/55 1976 UNIBUS 18-bit fast bipolar memory
11/60 1977 UNIBUS 18-bit writable control store
11/23 1979 QBUS 18-bit or 22-bit 0.12
11/24 1979 UNIBUS 22-bit first UNIBUS model to use F-11 chip 0.18
11/44 1979 UNIBUS 22-bit last non-LSI PDP-11 0.42
11/23+ 1981 Nov QBUS 22-bit 0.18
11/73 1983 QBUS 22-bit first J-11 machine, 15MHz, integrated FPU, also first PMI PDP-11
11/53 1984 QBUS 22-bit S-box or standard qbus, integrated FPU, 768KiW memory
11/83 1988 QBUS 22-bit J-11 at 18MHz, integrated FPU
11/84 1988 UNIBUS 22-bit J-11 at 18MHz, integrated FPU
11/93 1990 QBUS 22-bit J-11 at 18MHz, integrated FPU, 2MiW onboard memory
11/94 1990 UNIBUS 22-bit J-11 at 18MHz, integrated FPU, 2MiW onboard memory