Wagner WAC40

[Paul Koning]

> On Mar 13, 2021, at 1:34 PM, Joshua Rice via cctalk <cctalk at classiccmp.org> wrote:
> 
> 
>> Very interesting looking.  I can't quite make out what is going on in that rectangular area where all the wires terminate, labeled 0-15 and A-R.  Are there diodes there?  Anything on the other side of that board?
> 
> Nothing but traces on the other side, though you’re right on them being diodes.
> 
>> The large cores with all the wires are remisniscent of core rope ROM.   If so, I wonder if it's AGC (Lincoln Labs) style, EL-X1 style, or a scheme different from either of those two.
> 
> It’s definitely some form of core rope ROM. 
> 
> Interestingly, the ferrite rings are built in pairs, with a "selection" coil wrapped around both, joining them. Therefore (i assume, i’m really no expert) they’ll be a positive pulse induced when passing through one coil, but a negative pulse when passed through the opposite coil. This probably helps in differentiating beween a 0, a 1, or a NULL state (ie 0v). 
> 
> I have no idea if that correlates with any particular format of Core Rope, but as far as my eyes can tell, that’  how the core rope is woven and functions.

The key component of core rope memory (and X1 ROM) is square-loop cores, like the cores used in conventional read/write core memory.

There is another kind of core ROM where the cores are simply transformer cores.  Since you mentioned a "selection" coil, chances are that's what we're dealing with here.

Brent Hilpert has a great writeup on a number of the technologies used.  http://madrona.ca/e/corerope/index.html 

	paul