The weird stuff I keep finding: 19 bit core memory?
cz at alembic.crystel.com
Wed Oct 21 19:53:57 CDT 2020
My guess is the H215 has two more core fields on it since mine has 3 (18
bits plus parity). Odd they could fit up to 20 bits, maybe an early ECC
On 10/21/2020 7:17 PM, Noel Chiappa via cctalk wrote:
> > From: Richard Sheppard
> > There's a piece of core on eBay .. which claims to be H214. The interesting
> > thing is the label says 8K x 16 but the silkscreen says 8K x 19.
> DEC did that a lot; used one silkscreen (and etch) for two different modules,
> with differing componet sets to produce two different boards (e.g the MSV11-D
> and -E:
> M8044 and M8045 respectively; the boards all say 'M8045' in the etch, you
> have to look at the handles). The H214 is the 16-bit wide version of this
> board, used in the MM11-L UNIBUS memory:
> The parity MM11-LP uses the H215 (an 18-bit wide version), and a G109 instead
> of the G110 (again, same etch, some components left off for the G110.
> There's also an H213, used in the MM11-K:
> which is an 8KB version; the H213 looks identical to the H214 at first
> glance, but if you look closely the core mats are only half as dense.
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