Talk: PDP-11
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PDP-11 was flagged as needing attention because "this needs to be more easily understood".
Though it is a bit dry, I had no trouble understanding the article. Its terms appear to be well-defined.
What parts must be more easily understood??
[207.112.115.248]
If you are an assembly language programmer, it is perfectly clear. But most folks are not.
I think PDP-11 needs two more sections:
- On the social significance of the machine. Who used it? What did they do with it? What new feats did it enable? What was its market niche?
- Why did DEC build it? (The article almost answers this.) Why did they drop it? Is it associated with struggles within DEC? Did it make money for DEC? (Those of us who were fondly dependent on one or more DEC machines are deeply interested in this sort of thing.)
[207.172.11.147]
I am aware that the PDP-11 had the following types of applications in the 1980's:
- Academic institutions used them to train scientists and engineers in computer programming. The PDP-11 had a great little Fortran compiler and could service multiple terminals in a computer lab.
- They got used as remote communications processors to control printers etc. connected to mainframe computers.
- Siemens used duplicated-redundant PDP-11's to operate their telex exchanges.
I suspect that they also got a lot of use in industry as numerical machine or industrial process controllers. Basically the PC became more powerful and cheaper for the single user and industrial applications and the VAX was the natural upgrade path before computer servers came along. kiwiinapanic 10:19 Jan 20, 2003 (UTC)
I agree that it could use the sections suggested above (significance, and why it died). Alas, I don't have time to add them now - I just used my quota fixing the technical content! I'll add a bit about the second, though.
As to the technical content, a couple of fixes: the devices really did put an address on the bus (at least on the Unibus, haven't checked my Q-bus manuals); manuals show the interrupt vector being gated onto lines D02 through D08. The Unibus was a real bus, not just a backplane (old-timers will remember those long flat white Unibus cables), and although I don't recall using them for the Q-bus (perhaps for analog reasons), the Qbus really was a bus, not just a backplane. There were also 4 interrupt levels, BR4 through BR7; there was also the DMA-only NPR (you could do DMA on BR levels, but I don't know of any devices that did).
Sorry about all the extra RETURNs, and the numerous versions to fix them; I can't break the automatic habit of typing RETURN when I get near the end of a line!
Noel 16:06, 2 Mar 2004 (UTC)
