I think you mean 2S SD. That's 2-Sided, Single Density, aka a 160K/180K floppy. Doesn't your 360K drive (2S DD) handle it?

I mean 255D cause that's what the box says. I'm afraid just trying to read it with my 360K drive because it's such a rare game.

You might have misread the box, or the person making the box may have misread something (5 and S do look similar after all). I think that's the most likely as I'm pretty sure there's no such thing as a 255D floppy, but I do have 2SSD floppies (and even older ones too).

If it looks like a normal 360K disk, (which 2SSD floppies do), the worst that could happen is that DOS gives you a "general failure error" (the drive, or rather the controller claiming it can't read the disk). It won't damage the disk in itself unless the drive is malfunctioning, but then it'd damage other disks too. The reverse is also try. It won't damage the drive unless the disk is seriously damaged.

Just be sure not to *write* to the disk. There, you can cause problems due to varying track sizes and magnetic signal strengths.

you can see a scan of it here:
http://www.mobygames.com/game/dos/dunjonquest … meCoverId,3641/

that's not my scan and one can't read the sticker clearly but it says 255D. You might be right that it's a fault by the guy doing the box though.

so, I checked the manuals and there's a "How to Load" instruction. It says

HOW TO LOAD
TEMPLE OF APSHAI
EXPANSION MODULE
IBM: 235D, 255D

So there it is again, together with 235D which can hardly be a mistranscription. I guess those are kinds of either IBM machines or IBM disks from back then (remember, this is a 1983 game with the original game being from 1982). Someone surely remembers that stuff... I hope 😉

I'm gonna guess that those are then the type numbers of the IBM disk drives. At any rate, it should be fine in your existing drive, especially if you don't write to it.

No luck reading with my 360K drive 🙁

That means that game is probably meant to be read on a 1.2M drive. I started with an IBM XT and those came with either 160/180k singe-sided floppy drives or doube-sided 360k. When 80286 (AT) machines became more popular so did the 1.2M drives and more games were released on 1.2M floppies.

If you can find a 1.2M floppy I recommend upgrading your PC with it since it can read 160k/180k/360k diskettes as well. Good luck, it's tough finding vintage hardware. I'm glad I kept mine which allowed me to transfer Wing Commander to IMG files.

That is very unlikely. 5.25" HD drives had only just been invented when the game was released. Almost nobody will have had such a drive at that time. (I got my first 5.25" HD drive in 1988, a full 5 years later, and nobody else that I knew had one. All software still came on DD disks).

did you have to select the drive capacity in the bios ?

ps: did you try reading both sides ?

What operating system did you use? The modern ones might not care about these microscopic disk sizes.

As my DOS machine is not with me right now I could only try it out on a XP machine. My 360K floppy drive is supported by the BIOS and XP and I've backed up >100 disks with it already. So it's definitely working. Among those was a 180K disk iirc. So it's kinda weird that it doesn't read this one.

I tried a couple of tools to read from it (dd, WinImage, Unstoppable Copier, VGACopy) but none of them even detect a disk. I can give you the WinImage error msg (something about the format not being supported) later.

thanks for all your help 😀

(oh, and if someone wants to donate a 1.2MB drive you're very welcome. There's about two dozen games I couldn't backup yet because my 1.2MB drive broke...)