settings for DEC M7506 (MSV11-M)

Noel Chiappa jnc at
Thu Apr 9 06:52:44 CDT 2015

    > From: Pete Turnbull

    > Does anyone have a description of the switch settings for a QBus
    > MSV11-M (aka MSV1M) memory card (M7506)?
    > .. I can't find the manual ... or any useful notes anywhere.

How odd. I've looked through every plausible DEC QBUS document I've got, and
none mention the MSV11-M! They all jump straight from the MSV11-L to the
MSV11-P. E.g. the "Microcomputer Products Handbook" from 1985 has the
MSV11-L, then the MSV11-P, then the MSV11-Q. (Although it doesn't have the
MSV11-J either, though - although my MSV11-J manual says the first version
was '85.)

I wonder why? Was the MSV11-M a later card? (Well, it must have been...)

There's a Micro-Note (#28) from June '85 which mentions the MSV11-M, so it's
not _that_ late. However, e.g. the "Supermicrosystems Handbook", from 1986,
mentions the MSV11-J, then the MSV11-Q, then the MSV11-P!

I wonder why they left it out? It provides up to 1MB on a dual card, whereas
the MSV11-P only does 512KB on a quad card? So it's not as if it were already
obsolete by 1986 - it's clearly better than something they _did_ include!

Very odd.


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