[Info-vax] OT: Halt and Catch Fire

[Neil Rieck]

On Tuesday, June 2, 2015 at 11:25:53 PM UTC-4, JF Mezei wrote:
> Yeah, I know , "HCF, Halt and Catch Fire"  was an IBM 370 instruction in
> many "hacked" university documents.
> 
> It is also an AMC TV series now available on Netflix (at least in Canada).
> 
> Seems to deal with the emergence of the PC in early 1980s.
> 
> A curious to see if Digital will ever be mentioned or ignored. So far,
> one conversation had many companies listed and DEC was ignored.

As others have already pointed out, there was no HCF instruction but I have been told by people who worked on those machines that you could not stop the CPU on some IBM machines: Halt really meant the CPU went into a tight NOP loop (which is were the catch-fire myth comes from).

On the flip side, there were a lot of machines which could be stopped and even "single stepped". These machines included every mini I ever worked on starting with the Interdata-70 (an IBM-360 inspired clone) and PDP-11. I remember my Interdata-70 instructor back in 1976 saying something like: "being able to stop a CPU was only possible with fully-static CPU designs". So does anyone out there have any examples of a non-static designs?

As for the AMC series, there was no Cardiff Electric. Season-1 is really about Compaq Computer Corp who had the audacity to reverse engineer the IBM-PC. 

http://iq.intel.com/uncover-the-real-life-story-behind-amcs-halt-and-catch-fire/
http://www.internethistorypodcast.com/2014/05/the-incredible-true-story-behind-amcs-halt-and-catch-fire-how-compaq-cloned-ibm-and-created-an-empire/

Neil Rieck
Kitchener / Waterloo / Cambridge,
Ontario, Canada.
http://www3.sympatico.ca/n.rieck/