[Info-vax] OT: Halt and Catch Fire

[JohnF]

terry+googleblog at tmk.com wrote:
> On Thursday, June 4, 2015 at 3:27:36 AM UTC-4, JohnF wrote:
>> As pointed out, no model 69, though I do recall a 65. And I also
>> recall that list posted on the front panel of either our 360/30 or 40.
>> Let's see, it also had RSC=read and shred card, among maybe one or two
>> dozen other mnemonics. But I don't have a copy.
>> You think you could scan your copy and post a pdf somewheres???
> 
> Model 69 was probably part of the joke nature
> of the card that listed the HCF instruction.

Duh, okay, thanks, now I get it. But it's very annoying that
my computer apparently has a better sex life than I do.
  I subsequently googled those instructions and found a bunch
of hits, but those lists of joke mnemonics must be later editions,
much longer than the one I recall from the late 1960's.

> I never had an IBM CPU burn. I had a bunch of ITT Courier pseudo-3277
> controllers that tended to smolder. I told my students "What do you
> expect from a company that makes both atomic bomb parts and Twinkies?".
> The ITT service guy was NOT amused by my putting "Thank you for not
> smoking" desk signs on top of each of the controllers.
> 
> RSC is only implemented by the IBM 2560 MFCM (officially
> "MultiFunction Card Machine", but more commonly known as
> the "Mother-F****** Card Mangler") due to its 2 input hoppers,
> 5 output stackers, and the non-deterministic path between them,
> where a card might randomly encounter a read station, a punch
> station, or an interpretation station. The initial 90-degree turn
> and the subsequent 180-degree turn with rotation were added simply
> to frustrate the user or CE who attempted to determine where
> the 12-car[d] pileup had happened inside the machine.
> https://www.google.com/search?q=ibm+2560&tbm=isch
> 
> To briefly answer some later posts...
> 
> I'm pretty sure that it was called a "hard wait" state. Machine problems
> during IMPL didn't get that far (since there was no WAIT instruction
> loaded yet). There were a row of front lamps (top right by the "Emergency
> Pull", IIRC) with legends like "CPU EARLY", "CPU LATE", and my favorite,
> "SYSTEM DAMAGE". I had a 3125 (370/125) with an add-on memory cabinet
> from MAI (installed with a Sawzall and hundreds of wire-wrap wires
> coming out of the 3125 cabinet and into the memory cabinet), where if
> the add-on memory was powered on during IMPL, you got both a CPU EARLY
> and a CPU LATE. There was only a 30-second or so period to power it on,
> late in IMPL, so it would be detected and sized.
> 
> Microcoded CPUs generally don't have hardware-level HALT instructions -
> the microcode keeps spinning to detect changes in machine state and
> respond accordingly. Even microcoded systems with front panels had the
> front panel service routine (including single step) implemented in
> microcode.
> 
> For the ultimate reference to things IBMish, we'd need to tempt
> Lynn Wheeler to post here. http://www.garlic.com/~lynn/subtopic.html

-- 
John Forkosh  ( mailto:  j at f.com  where j=john and f=forkosh )