DEC H207 Core Memory Boards

[Ian King]

I just happened across a description of the MP8-E memory parity module.  It uses another core stack to maintain parity data for all other memory installed in the machine.  All core was 12-bit.  Source: PDP8/e Maintenance Manual, Vol. 2.  -- Ian 

> -----Original Message-----
> From: cctalk-bounces at classiccmp.org [mailto:cctalk-
> bounces at classiccmp.org] On Behalf Of Allison
> Sent: Friday, July 10, 2009 5:46 PM
> To: cctech at classiccmp.org
> Subject: Re: DEC H207 Core Memory Boards
> 
> There wass never ECC memory as the logic for that likely exceeds
> that of the PDP-8.  There was 13bit Parity memory (I don't mean the
> oddball
> 13bit rom /ram mix device).
> 
> 
> Allison
> 
> 
> >
> >Subject: Re: DEC H207 Core Memory Boards
> >   From: Ethan Dicks <ethan.dicks at gmail.com>
> >   Date: Fri, 10 Jul 2009 19:43:52 -0400
> >     To: "General Discussion: On-Topic and Off-Topic Posts"
> <cctalk at classiccmp.org>
> >
> >On 7/10/09, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
> >> While the use of the H207 has apparently been determined, out of
> curiousity was
> >>  there ever any ECC core memory for the PDP-8?, it might have have
> had a width
> >>  of 16 or 17 bits.
> >
> >I have never seen ECC core for any DEC machine (but don't take that as
> >the definitive answer).  The PDP-8/L, though, was commonly shipped
> >with parity (there's space in the CPU chassis that's pre-wired for the
> >parity support cards and the slots for the core sense/inhibit wires
> >are wired for 13 bits).  It might also be supported in the -8/i, but
> >I'd have to look that up (I know about the -8/L for certain because
> >one of mine arrived with that option populated).
> >
> >-ethan