🚀 go-pugleaf

JIM SHERWIN <shlump.nac.dec.com!video.dec.com@DECWRL.DEC.COM>
inquires about memory options:

>    Let me begin by apologizing that this query is originating from
>    w/in DEC.  It's regretful how quickly we've forgotten this
>    dandy little PC.  Enough said, on to my query.

That's o.k.  We understand all too well.


>    I have 2 PC100B (aka 100+) memory extension boards.  I am
>    wondering if I can combine the chips from them onto a single
>    board.  Doing so would entail using 256k and 64k chips on a
>    single board.  Here are the details:

>    [Details omitted]

The "Memory Board Option Installation Guide" (EK-RBMXE-IN-002) shipped
with the Rainbow memory expansion board shows many combinations of 64K
and 256K chips, so no problem there.

If I understand your description, you have one set of 256K chips and
two sets of 64K chips (total 128K).  So that would be 384K.  Added to
the 128K on the motherboard, this would come to 512K.

Configuration 4 on page 55 of the publication cited above shows just
such an arrangement, with the 256K chips in bank 1 (far right end of
the board when viewed with the memory chip sockets to your right) and
the 64K chips in banks 2 and 3.

With this configuration the switch settings are:
  1 - on
  2 - off
  3 - off
  4 - on.

Hope this helps.


Michael E. Macmillan
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