VOGONS


First post, by keenmaster486

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I am playing with my IBM PC AT, and I am wondering if there is anything better than just the default HIMEM.SYS for memory management. (I'm using DOS 5)

It has 512 K of base memory, and an Everex EV159 expansion card, which adds an additional 128K of base memory (to get the max 640K), and 1.5 megs each of XMS and EMS.

I tried FDXMS286.SYS, but that worked nearly identically to HIMEM.SYS, except it used slightly more conventional memory (about 1K).

What are my options here? It's a 286 so I can't use miracle-workers like JEMMEX or QEMM, which I'm used to.

I flermmed the plootash just like you asked.
World's foremost 486 enjoyer.

Reply 1 of 10, by maxtherabbit

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if your goal is to free up more conventional you pretty much only have the option of adding physical memory in to the UMA or hoping your motherboard chipset has shadow RAM functionality that can be repurposed to create UMBs

if you have a genuine IBM 5170, there's no shadow RAM to play with so you'd be limited to the "add physical" approach like the lo-tech 1MB RAM card

Reply 2 of 10, by maxtherabbit

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Your other option would be to switch to PC-DOS 7. It uses less conventional by a few kB and loads a larger quantity of the kernel into the high memory area IIRC

Reply 3 of 10, by Anonymous Coward

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DR-DOS. Maybe QRAM too.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 4 of 10, by keenmaster486

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maxtherabbit wrote on 2020-01-23, 00:15:

if you have a genuine IBM 5170, there's no shadow RAM to play with so you'd be limited to the "add physical" approach like the lo-tech 1MB RAM card

If I already have my Everex EV159 card though, wouldn't I not need that?

maxtherabbit wrote on 2020-01-23, 01:46:

Your other option would be to switch to PC-DOS 7. It uses less conventional by a few kB and loads a larger quantity of the kernel into the high memory area IIRC

Is that 286 compatible? I know MS-DOS 7 (Win9x DOS) won't boot on a 286.

Anonymous Coward wrote on 2020-01-23, 02:21:

DR-DOS. Maybe QRAM too.

Does DR-DOS use less RAM?

I'll try QRAM and see what happens.

I flermmed the plootash just like you asked.
World's foremost 486 enjoyer.

Reply 5 of 10, by Anonymous Coward

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DR-DOS comes with a 286 memory manager called EMM286. I think you can use it with other versions of DOS too.
At least out of the box, I remember DR-DOS providing more conventional memory than PC-DOS.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 6 of 10, by maxtherabbit

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PC-DOS 7 runs a treat on a 286 - and it uses less conventional than any other version of PC-DOS when paired with a 286+ system

I'm not familiar with your Everex memory card's layout, but the vast overwhelming majority of ISA EMS/XMS cards do not support mapping physical memory into the UMA

Reply 7 of 10, by kjliew

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maxtherabbit wrote on 2020-01-24, 03:16:

...the vast overwhelming majority of ISA EMS/XMS cards do not support mapping physical memory into the UMA

They don't, but the 64KB EMS Page Frame itself is memory, which can provide 64KB of UMB as long as there no one else is using true EMS then. I don't think it is possible for QRAM or any 286 UMB providers to manage EMS and UMB at the same time. None of the 386 EMS managers cannot do that, too.

Reply 8 of 10, by maxtherabbit

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kjliew wrote on 2020-01-24, 03:30:
maxtherabbit wrote on 2020-01-24, 03:16:

...the vast overwhelming majority of ISA EMS/XMS cards do not support mapping physical memory into the UMA

They don't, but the 64KB EMS Page Frame itself is memory, which can provide 64KB of UMB as long as there no one else is using true EMS then. I don't think it is possible for QRAM or any 286 UMB providers to manage EMS and UMB at the same time. None of the 386 EMS managers cannot do that, too.

Yeah, I didn't suggest using the page frame as a UMB because sacrificing access to all your physical EMS on a 286 for 64kB of UMB seems short sighted but it would work I suppose.

Reply 9 of 10, by keenmaster486

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I tried QRAM (version 2). It doesn't like the EMM.SYS that came with the Everex card. Either way it doesn't work right and I don't have any documentation for it, sadly.

I flermmed the plootash just like you asked.
World's foremost 486 enjoyer.

Reply 10 of 10, by Anonymous Coward

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Do you know if your EV 159 is LIM 4.0 compliant? I used to own a few of these cards, but never tested the expanded memory functions.

QRAM should be able to let you use UMBs and EMS at the same time if your card is LIM 4.0. Make sure your EMM driver is the latest one.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium