Get the CHS values from the same machine you intend to use the cards on.
You can put the attached utility on a bootable disk and run it from it, to see at least if you are getting the same values.

The problem is that the laptop came with broken FDD as well. But tried to use bios autodetection, IDEINFO and WHATIDE and they all gave the same values, on other system of course.

Just curious, what CHS values does your laptop see? what are the actual values reported by the drive?

Without a working floppy, here is what I would do:

1. go to a computer with a working floppy and make two diskettes:
   a DOS boot disk
   an EZ drive 9.03 boot disk http://vogonsdrivers.com/index.php?catid=19
   or EZ drive 9.09 if you are using a dos that understands fat32 A good FAT32 DOS, MS-DOS 7.1(Windows 98), DR-DOS Enhanced, FreeDOS?
2. mount your storage device on that computer as C:, along side another device that has all your software as D:
3. boot off the EZ drive disk and install the overlay software & dos boot sector on your laptop's storage device (you will lose all data on that device)
4. copy any other software installers you need from D: into a C:\Install directory on your storage device
5. put your storage device back in the laptop and complete the installs

Bernkastel7734 wrote on 2022-11-23, 16:47:

The problem is that the laptop came with broken FDD as well. But tried to use bios autodetection, IDEINFO and WHATIDE and they all gave the same values, on other system of course.

Can't you simply fix the floppy drive? How is it broken?
Seriously, the least stressful method is using a bootable DOS floppy and running FDISK/FORMAT.

The problem is the BIOS here. Using a different computer/BIOS to partition/format a HDD hardly works.

- The overlay trick *may* work, because it's directly installed in the beginning of the boot track.
However, using LBA is not expected below ~500 MB.
Not sure if the overlay will work with so little capacity.

The highest chance to get it to work is to make sure both PCs use exactly same BIOS.
If that's not possible, the manufacturer/type should be at least the same.

If your 386 has AMI BIOS, the new PC should have AMI BIOS, too.

Otherwise, a different drive geometry will be used.
Even if the values for C/H/S are exactly the same.

If you can't afford another PC with a matching BIOS, you cam try to use PCem/86Box.
They have machine settings for AMI BIOS, AWARD BIOS, etc.

By using Win32 Disk Imager, you can read/write binary images.
Use the image with the emulators, then write it onto the CF card.
- Be careful, though. The CF could be corrupted, at worst case.

Better make an image (read) first, then use that freshly created file for the PC emulator (FDISK/FORMAT, install DOS). Then write it back (write) to the CF.
That way, the CF card won't be overwritten too much.

I think I have another PC with the same AMI BIOS so I'll try to use it. The motherboard I was using got a Award one

Jo22 wrote on 2022-11-26, 15:42:

Can't you simply fix the floppy drive? How is it broken?

I guess misaligned heads, got ' bad address mark', 'CRC error' and 'sector not found' errors.

Bernkastel7734 wrote on 2022-11-26, 17:16:

Jo22 wrote on 2022-11-26, 15:42:

Can't you simply fix the floppy drive? How is it broken?

I guess misaligned heads, got ' bad address mark', 'CRC error' and 'sector not found' errors.

Ah, I see. Hm.. Could you (in theory) write a 360KB or 720KB floppy image of DOS onto an 1,44MB diskette ?
If you can do that, there's a chance it boots. In the past, those lower density formats still worked with bad drives.
WinImage might be able to help creating such a DOS image, also.

Otherwise, you can try using an emulator to create a bootable diskette.
Once it runs DOS, it's easy to make a virtual floppy DOS bootable..

Edit: Should be at least MS-DOS 5 (or 4, but that version is obscure) or similar (DR-DOS, PC-DOS, PTS DOS etc).E
Edit: These are just ideas, of course. You don't need to do that.

Have tried to use 720K floppy but it didn't change anything.

I’ve had good luck moving bootable storage devices with ez-drive between legacy computers even if they have different bios (AMI, Award, Phoenix, MRBios) or are from different eras. Booted on all of them. Never had a problem except for one C&T bios that would lock up before loading the boot sector if it saw a drive larger than 512MB, which was sort of a different issue. Ez drive also uses standard partition types so the volumes are accessible on contemporary USB readers under Windows 11 too.

Edit: But I usually use 2GB devices.

Hi again, is this the laptop?

http://retro-pc.ucoz.ru/index/tempo_vt386sx_20/0-1065

I have an idea. But I need your help.

I can try to make you a bootable HDD image, but I need an image of your CF card first (choose one).

a) Erase/format the CF in your modern PC.

b) Use Win32 Disk Imager to make a backup (read) of your empty CF card.
You should get an image of the size of your CF.

c) Now, do compress the image (make a ZIP file).
Since the CF is empty (filled with FFh?), file size should drop to a few KBs.

After that, sent me that file via PM or attach it in a posting down below.

Then I can try to use that image for installing a barebone DOS (Io.sys, ms-dos.sys, command.com - like a boot floppy).

I'll then send it back to you via PM.

It is not the laptop, but Your idea seems good. Will do that and send you that image.

It is around 21MB so it's too big for PM
https://drive.google.com/file/d/1NOrNYqT90B-7 … iew?usp=sharing

Both of those should be small enough that the BIOS isn't a limitation. I did happen to run across a very spoiled 16GB SanDisk CF card that absolutely required that FAT partitions have the LBA flag enabled, otherwise they wouldn't boot. I don't think that's the issue in this case, again, because the drives are so small. But it's worth a shot. The easiest way to add the flag is to boot into something like GParted. It's also possible with Linux FDISK, but this is requires explicitly setting the partition type and is otherwise a bit more complicated.

Bernkastel7734 wrote on 2022-11-28, 19:55:

It is around 21MB so it's too big for PM
https://drive.google.com/file/d/1NOrNYqT90B-7 … iew?usp=sharing

just an FYI, I had a look at the image, and the reason the zip file is so big is simple.
the CF card has never been erased. There is still data left over from the old cisco system it came out of.
edit: and the dos installs you previously attempted.

Fixed that I guess

Bernkastel7734 wrote on 2022-11-28, 21:21:

Fixed that I guess

Did you image the same card ?
Erasing and creating & formatting a partition shouldn't leave the data that is still present on the second image you posted.

Yup, I deleted a partition and the formatted it. But I have did that like 20 times already so don't know what's going on

maybe I missed it,
which CHS numbers are you using on the 386sx laptop?

490C 8H 32S