d87-psk@nada.kth.se (Patrik Skottsborg) (06/11/89)
I'm looking for a public domain or shareware program that will break the AT's 640k limit. I am NOT talking about normal EMS- or XMS-extention here. There exist a comercial product called 'MAX 386' which uses your expanded or extended memory to bring up the '640k' block to >752k on a 386-machine (using some 386-cpu feature). Is it possible to do something like this on a 286-machine ? Patrik Skottsborg d87-psk@nada.kth.se Royal Institute of Technology, Stockholm, Sweden ------------------------------------------------------------------------
davidr@hplsla.HP.COM (David M. Reed) (06/13/89)
I am probably wrong, but my understanding is that this cannot be done with a 286 chip as it is because it lack Memory Management such as is built into the 386 chip. I have come across a product, which I have not tried, that claims to allow this. Called the "All ChargeCard", from ALL Computers Inc., of Toronto, Canada (phone 416-960-0111). You remove your 286 processor and plug it into their Card, which in turn in then plugged into the 286 socket on the motherboard. It now provides memory management, and will allow (they claim) extending DOS to 960K, and use Extended Memory as Expanded Memory (just like is done with a 386 system). (They even claim that the multi-tasking/multi-user operating system PC-MOS/386 will then run on your 286 system.) I have not tried it yet because of the ~$500-$600 price, though others may consider this an inexpensive way to extend and fully utilized the capabilities of their system with its "brain-dead" 286 chip.
kjeld@iesd.dk (Kjeld Flarup) (06/15/89)
In article <1177@draken.nada.kth.se> d87-psk@nada.kth.se (Patrik Skottsborg) writes: >I'm looking for a public domain or shareware program that will break >the AT's 640k limit. I am NOT talking about normal EMS- or XMS-extention here. >There exist a comercial product called 'MAX 386' which uses your expanded >or extended memory to bring up the '640k' block to >752k on a 386-machine > (using some 386-cpu feature). Is it possible to do something like this >on a 286-machine ? Both yes and no. Normally the video RAM splits a 1Mb AT into at 640Kb DOS and then the rest is put into EMS. But however there is a gab between the video RAM and BIOS ROM. I have seen a program called himen which is able to load resident programs into RAM located in that part of the memory. These programs could be keyboard drivers or even sidekick. Thus it is possible to release more memory to DOS applications. To do this trick on a 80386 machine is no problem, bacause of the MMU. But on the 80286 there must be memory between video and BIOS. Some AT machines mirrors the EMS into that area. If you want to test this try this little Turbo Pascal line var teststring: string at $e000:0000; If you can work normally on this you may be able to use himem. Note that I haven't testet this, and there could be a conflict with EMS that causes the machine to crash. -- Kjeld Flarup Christensen | "I'am now thirty-seven times older than the universe kjeld@iesd.dk | itself." Marvin the depressed Robot.