AT&T 6386 Expansion memory boards (argh!)

[michael.rubin]

In article <3701 at infmx.UUCP> aland at infmx.UUCP (alan denney) writes:
>Does anybody have info regarding the memory address map for the socket
>on AT&T's "4/16 MB Memory Expansion Board" (PE Code 37337, Comcode
>406130534).  What I need is something that will tell me for any
>given address, which SIMM does it reside in by socket # and column #.

The 4-16 MB memory boards in my 6386 may be different from yours
since the sockets are not marked "U24", "U26" et al... they are marked
M09DS, L09ES, G09FS, ...

These boards have 8 SIMMs mounted horizontally on the left, 8 on the right
and two DIP switches in the top center (along with various other TTL).
According to the installation manual, the memory is arranged:

--0--	DIP DIP  --3--
--1--		 --2--
--2--		 --1--
--3--		 --0--
--0--		 --3--
--1--		 --2--
--2--		 --1--
--3--		 --0--

where 0 is the first meg of memory, etc.  There is no clue as to which
of the 4 SIMM's in a megabyte has the high order bits in the word.

--Mike Rubin <mike at attunix.att.com>