Uncreative Labs

Joined: 05 Aug 2008 Posts: 23

Is it possible to multi-task under Desqview on an XT class system? I have an old XT clone that I would like to setup as a dedicated DOS box. It's a 10MHz V30 CPU (I believe this has some 286 instructions), 640KB of memory, and a 20MB ST-238 Seagate.

I have an AST RamPage card with 2 megs on it. In theory I should be able to configure this via the dip switches on the card to run as EMS memory and install a memory manager like QRAM. But, do I need to backfill the memory on the motherboard, that is disable it down to 64K or as low as it will allow?

I also have an old Micropolis 72mb drive that I'd like to put in this system (has a ton of software and old games on it). Can I just plug 'er in to the existing controller or will it not work unless I do a low level format first.....which of course would wipe out the data?

TIA.

Joined: 03 Feb 2006 Posts: 488 Location: pennsylvanai

the relationship between a controller and a drive on an XT is very "picky"
if you have the super formatter WD bios it will see and read most drives other low level formatted drives.

The low level formatting on an AT is not compatible.
you could lose the data easily by just plugging it in,.
---------------------
let me digress.
with an at you can swap controllers back and forth.
most are based on the wd 1003 chipset ( including the ibm cards) 2:1 max interleave.
if the AT drive controller is based on the wd1006 (1:1)
it will work ok with AT drives that are formatted with wd1003 cards.
--------------------

back to the xt:
the xebex original IBM hard drive controller is DOG.
it is incompatible.

we wx2 cards older 2/3 length cards often have a short bios. for only 10 & 20 meg drives.
you can plug in a newer bios chip from a newer wx1
( square) card. and gain full function.

if the 71m drive was originally ll formatted with a WD controller in an XT, it will likely work if your present card has one of the newer bios chips.
I think the limit is 1024/16/17
the largest MFM drive was a 144?? it was a st4096 ( 80m) intended for RLL.
you stated you have a st-238 and it is 20 megs.
it is an RLL drive ( 615-4-616 and 17 sectors
instead of the 26 sectors for rll.

the rll drives get screwed up in a year or so
and require a low level format, this usually clears the errors.
if the controller for the xt is "27x" it is a rll controller.

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

Yes, from what I have read DESQView will "multitask" on an XT using LIM 4.0 memory board. Using the back filling EMS is ABSOLUTELY REQUIRED for this configuration so that you can use Large Page Frame EMS. You should try to set your motherboard memory as low as it can possibly go to make the page frame as large as possible.

May I ask which XT motherboard you are running. I also have an 10MHz V30 XT board, and I am badly in need of some documentation for it. I can't seem to get my FPU working with it. Would it be possible to post a picture?

Joined: 05 Aug 2008 Posts: 23

It is a Juko Super Turbo XT motherboard.

You FPU isn't taking the overclock very well?

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

In theory it shouldn't be overclocked. I think the board runs at 10MHz, rather than the 15MHz it was sold to me as. Do you have yours running with an FPU?

Do you have any documentation for your board?

I'd really like to see a photo also if possible.

Joined: 05 Aug 2008 Posts: 23

This looks the same as my board (green PCB and Juko ST sticker on the BIOS). I'm running a 10MHz V30, though. No FPU on my board. My BIOS is dated early 1990, pretty late in the game for an XT clone. Norton SI gives me a rating of 4.6....definitely 286 class performance, and if I am not mistaken _some_ of the 286 instruction set is included on the V30. It does run programs that are not supposed to run on an 8088 (Wolf 3D).

It did not come with docs which is why I am somewhat reluctant to mess with it.[/img]

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

You aren't getting that score of 4.6 using Norton Utilities v4.5a are you? It's notoriously inaccurate. The real score should be more like 3.5 XTs, and 3.7 after FASTV20.COM is loaded.

I've definitely seen the picture of the board you posted, but I am much more interested in an actual shot of your board. The V20 board you posted uses a slightly different planar, and the jumpers are not exactly the same.

Here's an actual shot of mine:

Does yours have this NEST BIOS as well. I believe it stands for something like National Electronics Super Turbo. My BIOS seems to have a date of 1988, so if yours is newer I'd really like a ROM dump. You're the only other person I know of with this board.

Joined: 05 Aug 2008 Posts: 23

Well, the computer is on my workbench in the garage at the moment. I am going to take it apart to clean the chassis and then put it back together with the EMS card and bigger hard drive. Might take a couple weeks at this point (work and other projects), but I'll take some photos when I do that.

I was definitely suspicious about the Norton SI rating. Landmark tells me that I am running the equivalent of a 7 MHz AT. That is with FASTV20 loaded.

Going back to the memory upgrade, I'd like as close to 640K conventional as I can get, with DOS and TSRs loaded high, and then I'd split the remaining memory for a ram disk (extended) and expanded for DesqView. I'd like to be able to run a couple of light weight DOS programs concurrently and use some of the >1MB memory for a ram disk with those programs. One of which is a C compiler.

I also have a Six Pack Plus with 384KB on it. Can I use this to fill in the 640KB-1024KB area and load stuff high, and then throw in my 2 meg RamPage (also have an Above Board with 2 meg) and split that 1/2 extended and 1/2 expanded?

Thanks again for your help.

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

Which version of Landmark gave you that result? I think I ran V6.00, and it reported my system as running as fast as a 10MHz AT. I don't think that is accurate though. Feels more like 7MHz AT to me.

As far as I know there is no way to use a SixPackPlus to map in the 640k-1024kb range. With a modification it might be possible, but that's beyond my ability.

Also, you can't use extended memory on a V30, because you still can't address more than 1mb of RAM. AST cards have a utility called REXX.SYS that can emulate extended memory, but it can only be used for ram drives and disk caches.

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

Oh. There's one more thing I wanted to bring up about backfilling with an EMS memory board. It will kill your memory performance. The memory installed on your planar is 16-bit, but the memory on an EMS board would be 8-bit. Your memory scores will drop by about half, which will probably have a big effect on overall system performance.