Hand-wired core for ROM?

[Brent Hilpert]

On 2015-Apr-10, at 12:29 PM, Brent Hilpert wrote:
> On 2015-Apr-10, at 9:32 AM, geneb wrote:
>> On Fri, 10 Apr 2015, William Donzelli wrote:
>> 
>>> You should probably cut him a little slack, since core and rope are
>>> easily confused, as they are so similar. Rope could be rewired in the
>>> field, but I certainly would not want to be the FE with that job.
>>> 
>> Yeah.  I think I'm just going to walk away from it. :)
> 
> Core RAM and "core rope" ROM sure are often confused, but technically I would disagree that they are similar.
> . . . .
> 
> Strikes me as conceivable that DEC used a field-configurable core rope design for the PDP-14 program memory - something like the PDP-9 module that Mattis linked to could be field alterable, but it sounds like "joe" in the OP thread may be confusing things.


This 1969 PDP-14 manual from bitsavers indeed describes a core rope ROM implementation for the control memory:

	http://bitsavers.trailing-edge.com/pdf/dec/pdp14/DEC-14-GGZA-D_PDP14UM_Nov69.pdf

It indicates the initial programming was generally done by specification to the DEC factory, but in-the-field reprogramming was also done.