daveb@geac.UUCP (David Collier-Brown) (04/25/88)
In article <76700015@uiucdcsp> gillies@uiucdcsp.cs.uiuc.edu writes: >I hope it's o.k. for me to ammend [sic --dcb] your list: >PDP-11: The addressing modes of this mini even influenced a major > language (C). Now that's influence!!! Well, that's an "urban legend". The pre/post-ops predated the 11, if one is to believe Ritchie. >Multics: The segmented architecture was imitated (unfortunately) by > the Intel 8086 - 8088 and esp 80286 (remember all those > articles in Electronics on "rings of protection" in the '286 ?) Sorry, that one's just plain wrong. The multics segments were a general-purpose mechanism with a few clumsy (ie, user-visible) restrictions. The intel segments were user-MANAGED [long, incoherent rant deleted]... and were different in both nature and purpose. The braying about 286 rings of protection in Electonics and the other Supermarket tabloids were back-patting by copywriters. Not to say that you couldn't **build** rings, because Intel did out of gates for its own operating systems, just that they weren't there. You could as easily claim that it had domains. >VAX-11: 2nd-place for CISC == Success. 9-11 cycles/instruction > These machines had a major influence on RISC designers > (e.g. disgust). Also, inept Berkeley computer designers > (small designs only!) and small dies in hands-on VLSI courses > had a big impact on RISC computers (just kidding). Well, probably third-place CISC if you consider the IBM 360 (which did about twice as much raw work per cycle, as the recent "VAX 11-780 MIPS" discussions implied). The IBM's instruction complexity was probably as much an influence as the Vax's. My favorite for a CISC (or vCISC) is actually the Honeywell level 66 "ICEbox", an instruction set expansion unit which made many COBOL or PL/1 statements into single instructions. This was folded into the base architecture quite soon after its invention, and does make it **quite** easy to write a certain class of code-generators for the level 66 and 68 machines. I suspect that other good (?) examples could be found. -- David Collier-Brown. {mnetor yunexus utgpu}!geac!daveb Geac Computers International Inc., | Computer Science loses its 350 Steelcase Road,Markham, Ontario, | memory (if not its mind) CANADA, L3R 1B3 (416) 475-0525 x3279 | every 6 months.