this post was submitted on 25 Apr 2024

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Trying to get DOS 6.22 on an SD Card, to then run via an ISA IDE to SD Adapter on my Commodore PC-10 III, but It doesn't wanna boot. What am I doing wrong? (lemmy.blahaj.zone)

submitted 6 months ago by [email protected] to c/[email protected]

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I have been following the exact steps as outlined in this tutorial video, with no oddities happening along the way: https://youtu.be/twQbHWJF7LA

Well, I was able to follow it up and until we got to the Partitioning part, where he says to load DOS up in the machine, presumably meaning the PC-10 in this case.

The PC-10 loads the ISA IDE to SD Adapter just fine, it even tried to look for Drive C (The SD Card) for like 10-15 seconds, until giving up then and there (as seen in the pic). (ISA IDE to SD card Adapter i got:)

In other words it seems that the Adapter either doesn't recognise what is on the Card and I've done something wrong in burning the provided image onto it or formating, or it doesn't recognise the card itself to begin with. Its a Brand new 32GB SanDisk SD so that be pretty suprising...

In other words... im out of ideas... i tried different DIP switch configurations and all, but no change. Perhaps the PC-10 III Simply doesnt like the Adapter... or can't run 6.22... im just out of ideas and frustrated. I've had this thing for over a month now with no luck in seeing it run once properly, and original 5,25" DOS Bootdisks are expensive and take a while to arrive. Should I just bite the bullet and go for one? I don't know. Any advice is much appreciated...

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[–] TootSweet 14 points 6 months ago (1 children)

Just some thoughts off the top of my head.

Did you burn the image to the partition on the card or to the card? (You'll want to do the latter.)
You might want to try booting from the card before expanding the partition to 2GB just to make sure the partitioning program isn't doing anything bad.
Can you check and see if one of the partitions on the card is marked as a boot partition?
Maybe just open the disk itself in a hex editor if you can and make sure whether the MBR seems to have bootloader code in it.

[–] [email protected] 4 points 6 months ago (1 children)

I did try to see if leaving the partitioning part out changes anything, and still nothing. Same thing as before. Also tried not changing sizes, same thing sadly.

As for the other 2 points, im afraid that I don't have the knowhow yet as to how to check those...

[–] TootSweet 5 points 6 months ago (2 children)

I'm not familiar with the tool they talked about for burning the image to the SD card, but can you share a screen shot of the options you used when burning the image?

[–] [email protected] 4 points 6 months ago

I'll do once im home in around 7 hours! In the mean time, I can definetly say that what the Video shows is 1 to 1 the same thing I saw while working with both programs and I followed them to the Pixel if that helps

[–] [email protected] 3 points 6 months ago (1 children)

Just got around to taking some screenshots.

First I press the "Flash from File" button and choose the DOS6.22 Ultimate .img

Then I select the Target, which is the SD Card

Then Lastly I press the Flash button and it does its thing

All ending without error on this screen

This is what the finished thing then looks like

Then I'd usually move onto the Partition Wizard.

Something odd I just noticed is that even after all the flashing and stuff, the card retains its original thumbnail saying "SD HC", would've thought that be gone by now, could that be an issue?

[–] TootSweet 3 points 6 months ago (1 children)

Ah! SDHC.

So, SDHC cards are a little different than regular SD cards (the protocol used to communicate with the card is a little different) and often aren't supported by particular SD card readers like potentially the SD-to-IDE adapter you're using.

(I know back in the day, I hacked my Nintendo Wii, which involved loading a bunch of homebrew programs on an SD card, and at first it didn't support SDHC cards until there was a firmware update.)

Technically, I think any SD card can be SDHC, but almost always SDHC is only used by high-capacity cards. Also, I think they usually say "SDHC" physically on the card.

So, probably the next thing I'd try if I was you was to change out your SDHC card for a non-HC SD card. Any 8GB to 32GB card should be fine, I'd think. (If you have any that are smaller even than that, like 256MB, even, you could at least use it to confirm that's the issue. You just couldn't expand the partition sizes out to 2GB.)

[–] [email protected] 2 points 6 months ago

I see, in that case I'll go to the store tomorrow and see if they got a tiny non HC SD card! Thank you!

[–] [email protected] 4 points 6 months ago (1 children)

Would FreeDOS work ? https://en.wikipedia.org/wiki/FreeDOS

[–] [email protected] 3 points 6 months ago (1 children)

I did think of that too after DOS failed, but from what I can find there only seems to be a floppy based installer for it? Since It doesnt have a working 3,5" drive, I can't install it via that. That or have I overlooked something while looking into it? Is there a way to burn it into an SD Card?

[–] [email protected] 5 points 6 months ago (1 children)

https://wiki.freedos.org/wiki/Main_Page#How_do_I_install_FreeDOS? There's more options than a floppy based installer to try.

[–] [email protected] 1 points 6 months ago

As far as I can see, the only one of these relevant to my XT Based PC-10 III would be the classic version which reads

For classic hardware: FreeDOS 1.3 includes a floppy-only edition! This edition should run on any original IBM PC system, including the PC, XT, and AT. Provides versions for 720kB, 1.2MB, and 1.44MB floppy disks.

Since it says its a floppy version, I'd asume I'd have to burn it onto a floppy and then install it? Or can I burn it onto the SD and then somehow boot it into the installer directly?

[–] [email protected] 3 points 6 months ago (1 children)

It's apparent it sees the SD card, but it's not seeing the MBR on it. I doubt the DOS version is the issue, because it's not event attempting to boot. Unfortunately there's no guarantee your 360kb floppy drives are in working order if you don't know already. I usually recommend a flash floppy but for an machine like this you're really getting into the weeds with it not being bootable. Try an different SD card, they can be weird, smaller is better. And try writing a different dos bootable image to it.

[–] [email protected] 1 points 6 months ago (1 children)

Yeah I'm getting a different SD card tomorrow. One thats notably not an HC SD card, which someone noted to probably be not compatible with the adapter.

[–] [email protected] 1 points 6 months ago

Well if that doesn't work I'll ship an 360kb boot disk to see if that helps. No guarantees it'll work.

[–] [email protected] 3 points 6 months ago

I haven't played around with SD adapters but there is a common problem with compact flash cards that gives the same symptom. They won't be bootable until you fire up DOS 6.22 and run FDISK /MBR, which is an undocumented command which gives no output but fixes the boot record. I would focus on getting the floppy drive working or buy a gotek so you can boot floppy images from USB and get into DOS that way.

[–] [email protected] 1 points 6 months ago* (last edited 6 months ago)

DOS disk interface is quite mundante. It was dependant on BIOS recognition, and its not compatible with 32 GB disk at all. An 120MB or 250MB HDD was the usual MS-DOS disk sold during the 6.22 era. The firsts GB disk ware common by 1996. By the way, 2GB is the max recognizable partition size. Use fdisk to create a Master Boot Record, and a 2GB partition, and try it. I tried it with ease with old 1 GB and 512MB Compact Flash cards, but I must say CF has almost direct compatibility with IDE. SD cards require an adapter controller (you seems to have one of those, tho).