PDA

View Full Version : XT-286 + 2MB extended Memory + DOS 3.3



MaTel
July 4th, 2010, 02:28 AM
Hello,

I own a IBM-XT/286 with a 2MB Memory-Extension. At boot the system recognize the extended Memory. But how can I use it under DOS 3.3 ? Do I need special software for that expansion board?

modem7
July 4th, 2010, 03:59 AM
You could use DOS 3.3's VDISK to use the extended memory as a virtual drive.
See http://www.woodboy.org/computing/msdos/vdisk.txt
So a line like the following would go into your CONFIG.SYS

device=c:\dos\vdisk.sys 2048 128 128 /e

Note that there is no central management/control of extended memory happening in DOS 3.3
VDISK will assume that it 'owns' the extended memory. If you run something else that uses extended memory, it will trample on the virtual drive.

MaTel
July 4th, 2010, 05:15 AM
ok. vdisk is one possibility to use the ram-expansion.

Are there other known DOS (Windows?) software, that use the extended memory under DOS 3.x?
I ask this because i want to know which people needed the ram-expansion on a 286-system.

glitch
July 4th, 2010, 06:12 AM
WordPerfect for DOS could be configured to use EMS rather than conventional memory. I believe AutoCAD's extender used EMS as well on pre-386 releases. There were also disk cache systems that could use EMS while leaving conventional RAM alone.

Chuck(G)
July 4th, 2010, 08:09 AM
Are we talking about EMS or XMS here? (XMS = extended memory above 1MB), (EMS = expanded memory; LIM, paged through a "window" in memory below 1MB). To run programs from it, the CPU needs to be in protected mode, so direct use of it was limited to Windows in standard mode and OS/2, Xenix and the like. Otherwise, you're selection is mostly limited to RAMDisks and cache programs.

Of course, the HMA (64K) is usable for storage, with the right driver. There are also many programs that can take advantage of extended memory for temporary storage and there are libraries like Ralf Brown's SPAWNO that allow programs to swap program space to it.

There do exist some emulators that claim to provide some LIM support using XMS and/or disk. In theory, one could run a multitasking app such as Desqview using one.

Raven
July 4th, 2010, 09:35 AM
My only experience with EMS is for some games, namely Monster Bash. It requires some small amount (I use 768K) of EMS to enable SB sound.

Chuck(G)
July 4th, 2010, 10:18 AM
My only experience with EMS is for some games, namely Monster Bash. It requires some small amount (I use 768K) of EMS to enable SB sound.

The original post was about Extended Memory XMS, not Expanded Memory, EMS. Very different fish.

MaTel
July 4th, 2010, 11:24 AM
The original post was about Extended Memory XMS, not Expanded Memory, EMS. Very different fish.

My question is, which software uses the capabilities of a ram-extension on a 286-System under DOS 3.x.

I know the differences between XMS and EMS. But both "systems" give DOS the possibility to use more memory than the first 640kb.

krebizfan
July 4th, 2010, 12:07 PM
Well, you could run Windows 3. I think that could install on DOS 3.3. I know Lotus 1-2-3 v3 was written for a 286 extended; there were about a dozen other programs that ran on 286 extended memory. There is also OS/2 1.x but you won't be on DOS 3.3 anymore.

If your card allows, you should probably reduce the extended memory and set some as EMS. MS's Smartdrv was much faster using extended memory than EMS. Windows 286 would use the HMA but if one wants the biggest benefit of HMA upgrading to DOS 5 or 6 is required. Desqview on a 286 needs EMS as does Windows 286. Splitting the memory as 512k extended (for disk cache and HMA) and 1.5MB EMS (for applications) works bests for most configurations unless running Win 3 or Lotus v3.