Extremely brief history of PDP computers

9 points by icefox

I quibble a bit with the bottom. VAX was intended more as a follow-on to the PDP-11 than the PDP-10. It was even called VAX-11 initially. It certainly subsumed that class of system but I don't think that was the original intent, and architecturally it was closer to the 11s.

kev009

Agreed, the PDP-11 was a minicomputer and the PDP-10 was a mainframe. The VAX was a minicomputer with clear PDP-11 heritage. Over time DEC did a good job covering low to high end with it and VAXclustering pushed it into unique space that covered the need of a separate mainframe ISA.
chbarts

VAX even stands for Virtual Address Extension, as an extension to the PDP-11, going from 16-bit to 32-bit. The whole 36-bit mainframe world died and there was no upgrade path, which lead to some interesting projects (ITS, WAITS, and Multics on a completely different 36-bit lineage) dying for lack of a newer platform to jump to.
- fanf
  The surviving 36 bit mainframe systems are these days emulated on commodity hardware:
  
  the Sperry UNIVAC 1100/2200 aka Unisys ClearPath Dorado https://en.wikipedia.org/wiki/OS_2200
  
  the GE / Honeywell / Bull 600 / 6000 series running GCOS (or Multics until about 25 years ago) https://en.wikipedia.org/wiki/General_Comprehensive_Operating_System
  
  Unisys also still supports 48 bit Burroughs Large System software under the name ClearPath MCP https://en.wikipedia.org/wiki/Burroughs_MCP
Garbi

If you're in western Pennsylvania and like old computers you might want to visit the Large Scale Systems Museum:

https://www.mact.io/