[Info-vax] Whither VMS?

[Richard B. Gilbert]

Bill Gunshannon wrote:
> In article <7iv384F31nq9iU23 at mid.individual.net>,
> 	Bob Eager <rde42 at spamcop.net> writes:
>> On Mon, 05 Oct 2009 20:15:13 +0000, glen herrmannsfeldt wrote:
>>
>>> Bob Eager <rde42 at spamcop.net> wrote:
>>> < On Mon, 05 Oct 2009 15:00:20 -0400, Richard B. Gilbert wrote:
>>>  
>>> <> It's not SUPPOSED to happen but Murphy says if it can it will!
>>>
>>> A good rule for computing hardware in general.
>>>  
>>> < Yes...in that case, the manufacturer insisted there was no fault. < So
>>> I wrote a microprogram patch....!
>>>
>>> Reminds me of the story of one IBM computer sometime before S/360.
>>>
>>> For S/360, the EX (execute) instruction is not allowed to execute
>>> another EX.  An earlier machine allowed it with a loop so tight that
>>> power cycling the machine wouldn't get out of it. (Core memory including
>>> the address of the next instruction.) The only way out involved magnets
>>> and opening the memory box.
>> I heard that on the Honeywell 516, a very tight loop (single instruction) 
>> would burn out core. Never tried it though!
>>> I know the PDP-10 has XCT, and I thought VAX would have one, but I don't
>>> see it in the book.
>> No, I don't see it, and I think I would have remembered it since I pretty 
>> well immersed myself in the VAX instruction set when writing a compiler...
>  
> Sounds like the HCF instruction reported to exist in some (in particular
> Motorolla) microprocessors in the dim dark past.
> 
> bill 
>  
>  
> 

I think HCF (Halt and Catch Fire) was invented by a humorist writing in 
"Datamation".  It might even have made into the book "Faith, Hope and 
Parity", a collection of humorous stories and cartoons culled from 
"Datamation".  I think that this was many years before Motorola got 
involved in the computer business!