The only way I can see that card being useful on a 286 like that is if you use it to fill in upper memory blocks, and then use third-party tools to load things into those UMBs, freeing up conventional memory elsewhere.

Be aware that the UMB memory would be slower, though.

bhtooefr wrote:

The only way I can see that card being useful on a 286 like that is if you use it to fill in upper memory blocks, and then use third-party tools to load things into those UMBs, freeing up conventional memory elsewhere.

Be aware that the UMB memory would be slower, though.

Thanks for the reply!.

How should I set the dip switches to set the 1MB card for UMBs?

According to the wiki https://www.lo-tech.co.uk/wiki/1MB-RAM-Board you set switches 2.3, 2.4, 2.5, 2.6 and 2.7 to "on"

stamasd wrote:

According to the wiki https://www.lo-tech.co.uk/wiki/1MB-RAM-Board you set switches 2.3, 2.4, 2.5, 2.6 and 2.7 to "on"

All of those "ON" ? 😲

I do not see the use of that card in a 286 system that has simm expansion. Because if the simms can provide the last 128kb of RAM it must provide upper memory blocks as well. All the remaining RAM will be extended meory. Unless the Sega Teradrive works in some weirder way...

Remove the Lo-tech card use HIMEM.SYS and check what MEM reports

^ As requested, after a fresh installation of MS-DOS.622 :

Also when it comes to some of the addresses, I've been told the Teradrive uses:

000h-A000h : for 640kb
A000h-C000h: VGA RAM
C000h-D000h-: some more Bios related.
D000h-E000h: EMS
E000h-FFFFh :128kb bios

Load emm386.exe and see add DOS=UMB to config.sys; see if MEM reports UMBs.

On a 286 machine ? 😳

stamasd wrote:

Load emm386.exe and see add DOS=UMB to config.sys; see if MEM reports UMBs.

Isn't emm386 for 386 and up pcs?

Edit: Jojo beat me to it 😀

Oops, my bad.
There are other packages that work for 8088 and up to enable UMBs. e.g. google "use-umbs". Try that and see if it enables any UMBs.

(edit) ftp://ftp.icm.edu.pl/pub/msdos/coast/memutil/use-umbs.zip

If the Teradrive uses all the UMA there's no point in thinking the Lo-Tech card can give you UMB's. All the UMA are is being provided by the RAM sticks.

So the VGA chip doesn't have its own dedicated RAM? Takes 64KB from the UMA? That's laaaaame no wonder that thing is so slow...

Very slow indeed 😵

So, there is nothing the 1MB card can do?

I also tried the Lo-tech 2MB EMS card, it works but keeps locking up.

Lo tech 1MB RAM cards are awesome in an XT.

Hold up, if the Teradrive has a dedicated EMS page frame in its stock memory map... that means that you'd need to configure EMS in whatever that thing has for CMOS configuration.

You also won't be able to use the Lo-Tech EMS card, unless you disable the built-in EMS.

carlostex wrote:

If the Teradrive uses all the UMA there's no point in thinking the Lo-Tech card can give you
UMB's. All the UMA are is being provided by the RAM sticks.

I admit I do know very little about the Teradrive, but the use of the SIMM memory can sometimes be configured in the CMOS utility.
If Shadow Memory or similar is disabled, it may not fill the gap between 640KB and 1MB.
The SIMM memory is then "mapped" beyond the 1MB boundary.
Or not mapped at all, depending on how we look at it:
Early 286s machines lacked the ability to relocate memory and skipped the UMA by default
(reasonable, because it was used solely for devices back then and memory was expensive).
Anyway, in this constellation it could be possible to use that UMB card along with on-board memory.
For what ever reason.

carlostex wrote:

So the VGA chip doesn't have its own dedicated RAM? Takes 64KB from the UMA? That's laaaaame no wonder that thing is so slow...

Wow, never seen that before. 😳
I thought that all VGA cards have at least 256KB, which is somehow mapped into a 64KB/128KB window.
The other way round is more familiar to me. Hercules cards' video memory can be used for creating UMBs.
I think there was a driver for this.. Anyway, other cards like CGA or EGA have very little memory, too, so it may be possible to not
use bank-switching techniques at all. At least for certain video modes.

bhtooefr wrote:

Hold up, if the Teradrive has a dedicated EMS page frame in its stock memory map... that means that you'd need to configure EMS in whatever that thing has for CMOS configuration.

You also won't be able to use the Lo-Tech EMS card, unless you disable the built-in EMS.

I wonder which type of EMS is faster, smoother or more compatible.
The Lo-Tech card has an 8Bit bus, but can do the mapping on it's own, thus lowering system overhead.
And in addition, it has modern memory so access times could be lower.

(Ronnie?)

Going back to the memory map, you mentioned this:

C000h-D000h-: some more Bios related.

This is the option ROM region. For instance, if you're using a card with the XT-IDE Universal BIOS, the card's ROM will occupy part of or all of this region.

There is 64KB between C000h and CFFFh, 32KB of which will be mapped to the XTIDE BIOS.

So basically out of everything between 640KB and 1024KB, you could potentially use a 32KB block between C000h-C7FFh or C800h-CFFFh for UMB. Is that worth occupying an entire ISA slot? Not IMO.

Jo22 wrote:

I wonder which type of EMS is faster, smoother or more compatible. The Lo-Tech card has an 8Bit bus, but can do the mapping on i […]
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bhtooefr wrote:

Hold up, if the Teradrive has a dedicated EMS page frame in its stock memory map... that means that you'd need to configure EMS in whatever that thing has for CMOS configuration.

You also won't be able to use the Lo-Tech EMS card, unless you disable the built-in EMS.

I wonder which type of EMS is faster, smoother or more compatible.
The Lo-Tech card has an 8Bit bus, but can do the mapping on it's own, thus lowering system overhead.
And in addition, it has modern memory so access times could be lower.

System overhead will be basically zero to use any onboard EMS emulation, and the memory will be handled at higher speed - the Lo-Tech card may even be running at half CPU clock speed or so, if it's not handling the zero wait state pin in the way that an AT expects. Combine that with a half bus speed, and even if there's a wait state involved in accessing main memory, that's still only 3 CPU cycles per main memory bus cycle, versus as much as 8 for the Lo-Tech card.

That is assuming that the comments about there being EMS already mapped into the Teradrive's memory are correct, and that it has EMS support in the chipset.

i run the lotech 2Mb EMS Board in a 286 16Mhz.

Even Wing Commander 1 runs very smooth with Sound and the 8Bit EMS Memory Card.
Its not so bad.. The Heatland EMS Driver for Onboard Memory is also no speed demon.
You can hardly tell any difference using the lotech board or onboard ems..

Can't you use the EMS page frame for 64kb of UMB if you're not using EMS? Using drdos himem.sys with /chipset:RAM?