Hi!
You will need a driver which knows your exact chipset for UMB,
unless you have a very verbose CMOS BIOS setup giving you some
fine-grained control over the configuration at boot already.
In your other mail, you show some MEM output which mentions
a driver LTEMM and FDXMS286, so I guess LTEMM is exactly that
driver for your chipset? You also load NNANSI, FDAPM, CLOCK (?)
and CTMOUSE. Not sure what EXP16 is. Shell is 4DOS and you
have FILES, LASTDRV and STACKS active.
In DRDOS, the MEM listing does not say which EMS driver you
loaded, but there is no CLOCK loaded there. Rest is similar,
but DRDOS uses less low RAM. No FILES, STACKS, LASTDRV etc.
In both cases, there are 15 MB of XMS "and" 2 MB of EMS. Do
UMB work with DR DOS? If yes, in which memory areas? Which
options or parameters do you use for the UMB and EMS drivers?
What exactly is the hardware on which you are running this?
other then "genuine harris 286 @ 25MHz with 16 MB of ram and @ mb of
EMS", how would this help you?
ok let me show the mobo
https://theretroweb.com/motherboards/s/pcchips-m218
it is this board exactly with lo-tech ems board and it has 16 mb of
XMS system ram
The VLSI VL82C311L (SCAMP-DT 286) chip of your mainboard chipset
https://theretroweb.com/chips/3036
supports shadow RAM and hardware-EMS. That means you can use EMS
on that 286 mainboard without needing a 386 CPU and without the
need, but also without the ability to load EMM386. Instead, you
would have to load an EMS driver for EXACTLY that mainboard chip.
The chip can also be used on mainboards for 386 CPU, by the way.
What is important for you is "Shadow RAM in 640K to 1M range"
and related features. The chipset can configure areas in 16kB
or 32kB blocks in the whole upper area from c000:0 to f000:ffff.
Each zone can be either: EMS (4.0 compatible), RAM, ROM / BIOS
or ISA card, or a combination, where reading and writing have
different endpoints, for example for shadowing.
Only zones where both reading and writing are configured as RAM
and not mapped AWAY from the first MB and not used for hardware
EMS can be used for UMB. The remapping can be useful because it
lets you use RAM for EMS or XMS which would otherwise be behind
ROM BIOS or similar at the same address between 640k and 1 MB.
But of course if some RAM is remapped to > 1 MB, it is no UMB!
You could even write your own driver. Pages 27-29 etc. for UMB,
continue to 36 to include EMS, etc. If you are VERY bored ;-)
Regards, Eric
_______________________________________________
Freedos-devel mailing list
Freedos-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freedos-devel
