The weird stuff I keep finding: 19 bit core memory?

[Chris Zach]

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 
(16b+4 ECC?)

C

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:
> 
>    http://gunkies.org/wiki/MSV11-D_MOS_memory
> 
> 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:
> 
>    https://gunkies.org/wiki/MM11-L_core_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:
> 
>    https://gunkies.org/wiki/MM11-K_core_memory
> 
> 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.
> 
> 	Noel
>