huilin@hpindda.HP.COM (Hui Lin Lim) (01/19/89)
I have a HIMS386 which uses a Mylex motherboard. It allows the
1M of onboard RAM to be configured as 640+384 or 640+0 or
512+512. According to the Mylex tech support the extended memory
always starts at 1M and this seems to be the case when I used the
system on its own. (Note that unlike several other boards the
Mylex does NOT use the 384K to shadow ROMs).
The trouble started when I plugged an AST Advantage with 1.5M of
RAM in. I thought that the simple answer was to configure the
card so that the 1.5M started at 1402K (1M+384K) since the
motherboard was set up for 640+384. My assuption was that I
would not have a system with 2.5M of RAM running from 0-640K and
1024-2944K, unfortunately the memory check on boot up only shows
2176K (640K+1.5M) while it used to show 1024K before I put the card
in.
The system will run Windows/386 OK so I presume I don't have a
hole in memory apart from 640-1M. The question is what happened to
the remaining 384K?
Mylex can't really help and suggested I call AST but I have a
funny feeling that AST will give me the opposite advice. Mylex
says that the memory check routines on power up look for ALL
memory and not just in 512K blocks and I've read all the manuals
thoroughly but can't find an answer. If any one has any
suggestions I'd be extremely grateful.
Mylex did suggest setting the m'board up as 512+512 then using
the Advantage to backfill 128K and have the rest start at 1.5M.
Problem is that I don't think the Advantage can be set up to do
that. Again any advice would be most appreciated.
Thanks.
Hui-Lin Lim
ARPA: huilin%hpda@hplabs.hp.com
UUCP: {ucbvax,hplabs}!hpda!huilin
Phone: (408)447-2835davidsen@steinmetz.ge.com (William E. Davidsen Jr) (01/24/89)
I think Mylex is right... I have used a Mylex board as 640+384 and all
of the memory was there, so their hardware works as advertized. I
*believe* that some models of AST board must be addresses on 512k
boundaries under some conditions (like using 256k chips). I would check
and see if your AST is in fact at 1MB, leaving you with 2 sets of chips
starting at 1MB for the next 384k.
--
bill davidsen (wedu@ge-crd.arpa)
{uunet | philabs}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me