Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!ukma!psuvm.bitnet!cunyvm!ndsuvm1!ndsuvax!ncoverby From: ncoverby@ndsuvax.UUCP (Glen Overby) Newsgroups: sci.space.shuttle Subject: Re: Shuttle Computer Info? Message-ID: <2645@ndsuvax.UUCP> Date: 6 May 89 22:56:18 GMT References: <24055@agate.BERKELEY.EDU> <3227@kalliope.rice.edu> Reply-To: ncoverby@ndsuvax.UUCP (Glen Overby) Organization: North Dakota State University, Fargo Lines: 25 In article <3227@kalliope.rice.edu> phil@hypatia.rice.edu (William LeFebvre) writes: >In article <24055@agate.BERKELEY.EDU> labc-4da@e260-4d.berkeley.edu (Bob Heiney) writes: >I don't know how much I can find out about the history of the programs >(design and implementation issues), but I can get an answer for just about >any technical question concerning the GPCs. >What else do you want to know? Thanks for the interesting info on the computers. I don't recall this from the 1984 CACM article. The flight software (both on the ground and on-board) gives me the impression of being crufty. On the failed attempt last Friday, the countdown was halted at 31 seconds; thats exactly when control of the launch is turned over to the on-board computers. So why do they decide to hold the launch at that point? Most of what causes the countdown to hold will have existed for several minutes at least, so why don't the ground computers decide to hold the launch then, or have the on-board computers say "I'm gonna hold when I get control". On another subject; I recall reading that the Shuttle's computers were so stuffed that to add something, something else had to be removed. With a 16MB address space, it would seem that more memory could be added and this could be avoided. -- Glen Overby uunet!ndsuvax!ncoverby (UUCP) ncoverby@ndsuvax (Bitnet)