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Intel AboveBoard: Curious beasts

ajrossnz

Member
Joined
Dec 30, 2019
Messages
19
Location
Wellington, NZ
Hi all,

I recently received my dream machine, the 5162 XT/286. I had the Intel AboveBoard lying around waiting for a home, so this seemed to be the perfect machine to try it out on.

My 5162 has 640K onboard RAM, so when it starts up with the AboveBoard in it, the mem count gets to 1664KB. I read the documentation a number of times, but I still can't understand why the board allocates all but 384K to extended (XMS) RAM, rather than Expanded RAM.

I don't really know what one can do with a machine of 286 era with XMS (as opposed to EMS). Maybe run win/286 or something? Anyway, Even though it gives 1024K to XMS, it shows 100% of that being used. The 384K which is given to EMM/EMS/Expanded isn't really enough to be useful - at least for the software I want to use it with. I can't see anything in the documentation about saying
a) Why it configures XMS at all.
b) Why 100% of XMS is allocated
c) how to not use XMS and use all of the RAM for EMM.

I attach a screenshot of mem /c showing how XMS has 1MB of RAM, yet 0K free, whilst EMS has only 384K but has 100% free.

Any clues on how to use just EMS? And if any of you are using extended or expanded RAM for your low-end PCs (i.e. 286 and below), what do you use it for?

IMG_20210220_002323.jpg

Cheers,
Alistair
 
Minuszero has an Aboveboard Shortcuts to Installing Above Board for DOS Experts. Look for it.

Extended memory can be used for OS/2 1.x or Windows 3 or Lotus 1-2-3 R3. It is a good idea to have at least some since you are using a late version of DOS which supports the HMA which reduces DOS's needs in the lower 640K by 64K.

What is in the CONFIG.SYS and AUTOEXEC.BAT? Do you have an extended memory RAMDISK or disk cache running?

To not use any, set the left set of switches to OFF which gives no extended memory and the card should use all the memory as EMS. Note that few programs use much EMS either so most of the memory would need to be assigned to a disk cache.

I think dropping the extended memory to 512K to provide 64K of extended for HMA reserving the rest for EMS would be best for your described usage. I am puzzled by the 384K of EMS which seems most likely if the card is trying to backfill 128K but that shouldn't be done if the system already has 640K on the motherboard. Could you verify the actual memory total on the board? Does the card have 1.5 MB which would be 6 banks of 256 kbit chips?
 
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