Joshua: I have one of those too. They do make a great display piece. If you collect any information off list, I would love to hear it.
On Sun, Mar 14, 2021 at 11:20 AM Paul Koning via cctalk < cctalk@classiccmp.org> wrote: > > > > On Mar 13, 2021, at 1:34 PM, Joshua Rice via cctalk < > cctalk@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 > >