Hand-wired core for ROM?

[Johnny Billquist]

On 2015-04-10 18:00, Rod Smallwood wrote:
> Not seamstresses but nimble fingered girls in Puerto Rico and the
> Phillipines
> Core was in effect ROM. Power the system down switch off and anytime
> later turn it back on and whatever was
> in core was still there. I can remember our  Field Service guys
> restarting the final factory diagnositc on new systems.

But... That is not what ROM is. You are just talking about store that 
persists over power failure. You can still overwrite it whenever.
And actually, reading core is destructive. So you can never have core 
for rom. It needs to be rewritten whenever it is read.

	Johnny

>
>
>
> On 10/04/2015 16:32, geneb wrote:
>> On Fri, 10 Apr 2015, Paul Koning wrote:
>>
>>>
>>>> On Apr 10, 2015, at 10:38 AM, geneb <geneb at deltasoft.com> wrote:
>>>>
>>>> Did the PDP14 (or any machine of that era) ever use hand-threaded
>>>> (by the end user) core boards as ROM?
>>>
>>> Do you mean DEC machine?
>>>
>> Yes.
>>
>>> I don’t know any.  Certainly not any PDP-11; those used solid state
>>> ROMs, or in the early boot ROM cards, diode arrays.
>>>
>> I want to make sure it wasn't in use before I double-down on calling
>> shennanigans on "Joe" in this thread:
>> http://hackaday.com/2015/04/08/restoring-a-vintage-pdp-1104-computer/#comments
>>
>>
>> As far as I know, machines of that era used cores that were so small
>> the DEC hired master seamstresses (myth?) to make them. It's certainly
>> not something that would be done in the field by John Q. Programmer.
>>
>> If I'm wrong, I'll happily admit it, but it just doesn't sound
>> reasonable.
>>
>> Thanks!
>>
>> g.
>>
>