rasz_pl wrote on 2026-06-11, 10:35:

Weird chipset choice to map this ram to a window at 2000:0 (128KB) instead somewhere at the top. Makes EMS emulation very slow (copying data around).

Yeah, it's essentially a limulator except using this oddball memory instead of XMS or disk.
Incidentally, XMS could be another way to expose the 384K.

Babasha, I've heard of these Juko 128K-512K bank switching memory implementations before. I've thought about whether you have to keep interrupts off while having the opposite memory bank switched in. If the main program is aware of the bank switching, I suppose not, unless there are already drivers or TSRs loaded there.

jakethompson1 wrote on 2026-06-12, 19:27:

Yeah, it's essentially a limulator except using this oddball memory instead of XMS or disk. Incidentally, XMS could be another w […]
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rasz_pl wrote on 2026-06-11, 10:35:

Weird chipset choice to map this ram to a window at 2000:0 (128KB) instead somewhere at the top. Makes EMS emulation very slow (copying data around).

Yeah, it's essentially a limulator except using this oddball memory instead of XMS or disk.
Incidentally, XMS could be another way to expose the 384K.

Babasha, I've heard of these Juko 128K-512K bank switching memory implementations before. I've thought about whether you have to keep interrupts off while having the opposite memory bank switched in. If the main program is aware of the bank switching, I suppose not, unless there are already drivers or TSRs loaded there.

Its better to look at RAM-drive diver disassembled and commented by Indrekis (just translate it)
https://indrekis.github.io/retrocomputing/ibm … %8F%D1%82%D1%8C

rasz_pl wrote on 2026-06-11, 10:35:

Weird chipset choice to map this ram to a window at 2000:0 (128KB) instead somewhere at the top. Makes EMS emulation very slow (copying data around).

Love indrekis blog, had to resort to google translate to read but it was worth it https://indrekis-github-io.translate.goog/ret … &_x_tr_pto=wapp
all blog posts https://indrekis-github-io.translate.goog/pos … &_x_tr_pto=wapp

Indrekis found one BIG bug in EMS driver - in some circumstates stack can be lost during memory switch (in DOS its not so frequent while Windows 3.0 freezes more frequent). I hope in next version 1.3(?) get more stability and compatibility)))

Babasha wrote on 2026-06-12, 19:22:

Next step. Case for my rig.

Little baby or Big brother what you choose?

An XT shouldn't exist without a 5.25" 360KB floppy!

About your SCSI Controller. You know this thread?
Re: Making Future Domain TMC-850MEX SCSI controller bootable

eisapc wrote on 2026-06-15, 10:48:

About your SCSI Controller. You know this thread?
Re: Making Future Domain TMC-850MEX SCSI controller bootable

Tnx!

I know))) Currently i dont ready to solder it and it was so interesting use BIOS EXTENSION socket on motherboard

Some news about shadow RAM usage (part 1)
After bug-hinting by Indrekis and help of GlaBIOS author the EMS driver is way more stable with JUKO ST-12 and SCSI card/HDD
Now it boots and work in Windows 3.0 + Word 1.0

Some news about shadow RAM usage (part 1)
Use shadow RAM as a RAM-disk + benchmarks.

1. SCSI HDD speed

2. Original JUKO RAM-disk driver (direct mode)

3. Universal EMS RAM-disk driver

HI, @Babasha,
This is very useful thread, thank you!

Babasha wrote on 2026-08-03, 20:17:

3. Universal EMS RAM-disk driver

By "Universal EMS RAM-disk driver" do you mean EMSDSK86.EXE ?

aVd wrote on 2026-08-04, 08:13:

HI, @Babasha, This is very useful thread, thank you! […]
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HI, @Babasha,
This is very useful thread, thank you!

Babasha wrote on 2026-08-03, 20:17:

3. Universal EMS RAM-disk driver

By "Universal EMS RAM-disk driver" do you mean EMSDSK86.EXE ?

I use Turbo RAM disk driver from italian programmer. This driver can use convertional/XMS/EMS memory for RAM-DISK

Babasha wrote on 2026-08-04, 11:55:

I use Turbo RAM disk driver from italian programmer. This driver can use convertional/XMS/EMS memory for RAM-DISK

Turbodisk by Ciriaco Garcia de Celis? Please, could you share it or share some normal (non-ftp) link for download?

aVd wrote on 2026-08-04, 12:09:

Babasha wrote on 2026-08-04, 11:55:

I use Turbo RAM disk driver from italian programmer. This driver can use convertional/XMS/EMS memory for RAM-DISK

Turbodisk by Ciriaco Garcia de Celis? Please, could you share it or share some normal (non-ftp) link for download?

Yes its free software

http://www.retroarchive.org/garbo/pc/memutil/index.html
http://old-dos.ru/index.php?page=files&mode=f … =show&id=102775
TDSK with sources

Thanks for the working links, @Babasha!

It looks like, that the attached "TDSK.EXE.zip" contains TURBODSK Spanish version 2.1 (the developer is from Spain, not from Italy, even if its name sounds kinda Italian too), which is not the latest one.

I downloaded the latest available version 2.2 from the links.

And look what I just shared: Re: Unique (Juko ST) UX Turbo XT Mainboard - utility diskette This attachment contains newer versions of drivers for JUKO ST motherboard.

aVd wrote on 2026-08-05, 06:01:

Thanks for the working links, @Babasha! […]
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Thanks for the working links, @Babasha!

It looks like, that the attached "TDSK.EXE.zip" contains TURBODSK Spanish version 2.1 (the developer is from Spain, not from Italy, even if its name sounds kinda Italian too), which is not the latest one.

I downloaded the latest available version 2.2 from the links.

And look what I just shared: Re: Unique (Juko ST) UX Turbo XT Mainboard - utility diskette This attachment contains newer versions of drivers for JUKO ST motherboard.

Tnx for your utils!
Test it with my JUKO - sad they works only if 640KB convertional RAM available (same as EMS driver before patch from @Indrekis). My JUKO have only 639KB free convertional RAM (SCSI card eats 1KB for disk buffers). So i check only RAM-disk driver CDISK.SYS (i boot from floppy without SCSI card and HDD) and it works OK.
My next steps are try to patch this version of utilities to work with my or any ammount of free RAM. Or i resolder SCSI card for SCSI BIOS v. 8.2 without 1KB buffers in RAM.

Babasha wrote on 2026-08-05, 19:51:

Tnx for your utils!
Test it with my JUKO - sad they works only if 640KB convertional RAM available (same as EMS driver before patch from @Indrekis). My JUKO have only 639KB free convertional RAM (SCSI card eats 1KB for disk buffers). So i check only RAM-disk driver CDISK.SYS (i boot from floppy without SCSI card and HDD) and it works OK.
My next steps are try to patch this version of utilities to work with my or any ammount of free RAM. Or i resolder SCSI card for SCSI BIOS v. 8.2 without 1KB buffers in RAM.

Sorry, I forgot about the 639 KB (or less) detected conventional memory bug in the EMS RAM driver. These newer drivers will definitely need some disassembly and patching.

Hi, @Babasha,
The final version of the JSTWSR tool is released now: New DOS Tools for Juko ST motherboard and XT clones based on VDL C1, TD3300A, NEC 567 or Hitachi HG62E22R36FS chipset

Thanks for your testing and detailed feedback!

aVd wrote on 2026-08-11, 14:07:

Hi, @Babasha,
The final version of the JSTWSR tool is released now: New DOS Tools for Juko ST motherboard and XT clones based on VDL C1, TD3300A, NEC 567 or Hitachi HG62E22R36FS chipset

Thanks for your testing and detailed feedback!

Tnx for your work and one more great utility for JUKO ST-12!

If you want quick and dirty boot-up from FDD so you can use every 16-bit ISA multicard. It will support FDD/COM/LPT/GAME ports bit not HDD. You can use any 1.44 floppy drive and usual floppy disk as 360 or 720KB modes 😉

Babasha wrote on 2026-08-11, 16:43:

Tnx for your work and one more great utility for JUKO ST-12!

Thanks! I'm already working on even better tool for setting the wait states with command line parameters, which is based on JSTWSR. Probably tomorrow I'll come with something usable for tests.

Babasha wrote on 2026-08-11, 16:43:

If you want quick and dirty boot-up from FDD so you can use every 16-bit ISA multicard. It will support FDD/COM/LPT/GAME ports bit not HDD. You can use any 1.44 floppy drive and usual floppy disk as 360 or 720KB modes 😉

Interesting. I didn't knew, that I can use any 16-bit ISA multi I/O+FDD+HDD controller without its HDD part on 8-bit ISA slot. Thank you for this information! If this gonna work for me, then I could test these tools during development by myself 😀

aVd wrote on 2026-08-11, 16:54:

Thanks! I'm already working on even better tool for setting the wait states with command line parameters, which is based on JSTW […]
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Babasha wrote on 2026-08-11, 16:43:

Tnx for your work and one more great utility for JUKO ST-12!

Thanks! I'm already working on even better tool for setting the wait states with command line parameters, which is based on JSTWSR. Probably tomorrow I'll come with something usable for tests.

Babasha wrote on 2026-08-11, 16:43:

If you want quick and dirty boot-up from FDD so you can use every 16-bit ISA multicard. It will support FDD/COM/LPT/GAME ports bit not HDD. You can use any 1.44 floppy drive and usual floppy disk as 360 or 720KB modes 😉

Interesting. I didn't knew, that I can use any 16-bit ISA multi I/O+FDD+HDD controller without its HDD part on 8-bit ISA slot. Thank you for this information! If this gonna work for me, then I could test these tools during development by myself 😀

Not just ISA16 but and VLB. My first JUKO start was with VLB monster multicard FLOPPY/COM/LPT/GAME/IDE/SCSI. And it works with FLOPPY/COM/LPT/GAME))))