1 Feb
2017
1 Feb
'17
10:06 a.m.
On Feb 1, 2017, at 1:02 PM, Paul Koning <paulkoning
at comcast.net> wrote:
Never mind, that was all wrong. It takes only 2*n wires to select one of 2^n cores in a
core-rope ROM, so far that was correct. But the number of ROM words equals the number of
cores (obviously). So if there are 16 cores that would mean 16 words, but it also means
that only 8 drivers are needed (4 address bits). So there's a puzzle.
paul
On Feb 1, 2017, at 11:57 AM, Rick Bensene
<rickb at bensene.com> wrote:
Mr. Havermout wrote:
If it's a core-rope ROM, which seems plausible, then it would be 256 x 16. Core rope
uses 2 select ("inhibit") lines/drivers per address bit. So 16 drivers means 8
address bits, i.e., 2^8 words. Can someone identify this circuit board? It's
some sort of magnetic core
memory. I've had this for ages and I've always wondered what it is and
where it comes from.
http://lookpic.com/O/i2/366/iAFq4mLF.jpeg
Whatever this was, it appears that it has been scavenged for parts over time. Many
components appear to be missing.
It seems to me from looking at the board carefully that it could be a small wire-rope
ROM, or, perhaps the cores (one module has its cover removed exposing the large ferrite
rings) serve as pulse transformers for magnetic core that resides on another circuit
board.
If it is a small wire-rope read-only memory, it appears that it could be a 16x16 ROM,
perhaps hard wired for some kind of small bootstrap loader or the like.
It looks like there are 16 wire drivers (two of the driver transistors are missing), and
16 sense amplifiers. 