ching@pepsi.amd.com (Mike Ching) (05/29/90)
My AT has forgotten how to map memory from 640K-1M to extended memory. Can anybody help? Details: 286 clone with C&T chipset and Award BIOS. It used to work and I changed to a newer BIOS version that included setup in the ROM. Now it maps the 1Meg into 512K base and 512K extended instead of 640+384. Putting the old ROMs back and using the old setup program doesn't change things back to the original condition. Losing base memory is a disaster. Help! Mike Ching ching@pepsi.amd.com
david@gisatl.FIDONET.ORG (David Deitch) (05/30/90)
In a message of <May 28 17:06> Mike Ching (ching@pepsi.amd.com ) writes: > My AT has forgotten how to map memory from 640K-1M to extended > memory. Can anybody help? > > Details: 286 clone with C&T chipset and Award BIOS. It used to work > and > I changed to a newer BIOS version that included setup in the ROM. > Now > it maps the 1Meg into 512K base and 512K extended instead of > 640+384. > Putting the old ROMs back and using the old setup program doesn't > change things back to the original condition. Losing base memory is > a > disaster. Help! Mike, most likely you have accidentally reset the base system memory switch on your motherboard. Check your docs and make sure it is set for 640K system memory. David Deitch (GIS) deitch@gisatl.fidonet.org 1:133/411@fidonet -- ----------------------------------------------------------------------------- David Deitch - via FidoNet node 1:133/411 UUCP: galbp!gisatl!david INTERNET: david@gisatl.FIDONET.ORG
ching@pepsi.amd.com (Mike Ching) (05/31/90)
In article <1255.26634CFE@gisatl.FIDONET.ORG> david@gisatl.FIDONET.ORG (David Deitch) writes: >In a message of <May 28 17:06> Mike Ching (ching@pepsi.amd.com ) writes: > > > My AT has forgotten how to map memory from 640K-1M to extended > > memory. Can anybody help? > > > > disaster. Help! [ most of my original post deleted] > > Mike, most likely you have accidentally reset the base system memory >switch on your motherboard. Check your docs and make sure it is set for >640K system memory. > Sadly I've already tried setting memory to 640K (out of desperation) and it turns the memory to a total of 640K with the other 384K ignored. I KNOW the mapping feature can be enabled/disabled, just not how to do it. The C&T data sheets only address hardware and say nothing about programming the chips. I guess it's not necessary to publish anything if there are only a handful of BIOS programmers who need to know. I guess memory is cheap enough to throw away 384K but it's annoying to know it's there and SHOULD be available. Mike Ching
phil@pepsi.amd.com (Phil Ngai) (06/01/90)
In article <1990May31.061805.15760@bach.amd.com> ching@pepsi.amd.com (Mike Ching) writes: |Sadly I've already tried setting memory to 640K (out of desperation) and |it turns the memory to a total of 640K with the other 384K ignored. I |KNOW the mapping feature can be enabled/disabled, just not how to do I believe that some very early chip sets indeed could not map the 384K to extended. Your system matches the other thing I heard, which is that your other configuration is 512+512. I suspect you have a very early machine because you are the guy with a seven megabyte hard disk, as I recall. -- Phil Ngai, phil@amd.com {uunet,decwrl,ucbvax}!amdcad!phil "Separate but equal": bad for blacks, good for women.
nelson_p@apollo.HP.COM (Peter Nelson) (06/01/90)
From: ching@pepsi.amd.com (Mike Ching)
:Sadly I've already tried setting memory to 640K (out of desperation) and
:it turns the memory to a total of 640K with the other 384K ignored. I
:KNOW the mapping feature can be enabled/disabled, just not how to do
:it. The C&T data sheets only address hardware and say nothing about
:programming the chips.
My 386SX generic clone ("Magitronics" motherboard) also has
C&T chips (their NEATSX chip set) and with the computer I got
a disk of NEATSX utilities which set the chips (interleaving,
memory configuration, wait states, shadow RAM, etc, etc...lots
of stuff.) This is very handy although I imagine you can really
shoot yourself in the foot with it if you're not real careful.
Have you tried contacting C&T to get more information? Tell them
what chip set you've got and they'll probably send you a utility
disk.
---Peter