Harry Potter wrote on 2023-04-08, 19:58:

the last time I tried to install JAM on a Win98SE system, it didn't load at all: it complained that it was incompatible with my system. 🙁

What version did you try? I'm looking at 1.25 shareware (which is the latest version that was ever on simtel as far as I can tell) and its README.DOC says:

5.1. DOS versions
-----------------

The JAM 1.25 is fully compatible with the following Disk Operating Systems
(Control Programs):

1. PC-DOS 3.30, 5.02, 6.01, and 6.3
2. MS-DOS 3.30, 4.01, 5.0, 6.0, 6.2, 6.22, and 7.0
3. Compaq DOS 3.31, 5.0
4. DR-DOS 6.0 (April 1992 and earlier releases)
5. DR-DOS 6.0 March 1993 "business update"
7. Novell DOS 7

NOTES:

1. To prevent possible conflicts with other Disk Operating Systems,
we have not tested, JAM driver checks the DOS OEM number. If DOS
version is between 3.30 and 7.0, but OEM number is neither 00h
(IBM), 01h (Compaq), nor 0FFh (Microsoft), the JAM driver will
display the error message like:

'Warning: Incorrect DOS OEM number.'

In this case (or in case if you have newer release of PC-DOS,
MS-DOS, or Novell DOS than listed above) you could contact us for
upgrade information (see section 8. Technical Support below).

I think the DOS version in Windows 98 SE is greater than 7.0 (7.10?) so JAM probably won't be happy with that. Perhaps you can make JAM think it's version 7.00 using SETVER, but I gather that it requires a driver to be installed in CONFIG.SYS and I'm not sure if SETVER works for drivers.

Were you trying to use JAM within Windows? Since it is a driver, I'm not sure how well it would work inside Windows. Perhaps if you get it to mount the drive before Windows starts it will just show up as some kind of legacy 16-bit drive (I assume Windows 98 SE still supports them like Windows 95 did), but I don't think you could mount and unmount drives within Windows. In fact I don't even know if that would work, perhaps the best you can hope for is to be able to use JAM when you boot into DOS mode (assuming SETVER works).

Disclaimer: I only read a little bit of the README.DOC so I probably don't understand how it works that well but I think I get the vague idea. I assume it's like DoubleSpace/DriveSpace, although I never used those either.

Okay, I'm sorry. 🙁 I think that was the version I had. Unfortunately, I still can't run it, as it will cost me 32-bit Windows disk access. 🙁

I'm not sure why you apologised, sorry if you found my message rude for some reason!

Yeah, I don't think I'd want to lose 32-bit disk access either! DOS mode is probably the only option then.

Maybe if you can get it working in DOS mode, you wouldn't have to have it running all the time when in DOS mode - you could create a shortcut which runs in DOS mode and includes the necessary CONFIG.SYS and AUTOEXEC.BAT parts in the shortcut so you basically have a shortcut which starts DOS mode with JAM. You could just start it whenever you want to get something off one of those floppies, but at that point maybe you could convert the floppy to use DriveSpace instead (I think that works with floppies from what I read online just now) or copy the files to your hard drive so you don't have to boot into DOS mode too often.

Well, I actually have many floppies compressed with DriveSpace from an old Win98SE computer, but I also had a DOS laptop on which I used JAM and 2M to get more disk space, and I want to use those disks. You're right, though, I could create a shortcut and use it to boot to DOS. Thanks! 😀

About 2M: its docs say that I can use it within Windows 95, but it will result in poor performance. Two questions: how do I disable 32-bit virtual drivers for the floppy and use the real-mode drivers for the floppy? How much of a performance hit would I expect from this? If it's small, it might be worth it. If major, it probably isn't.

Interesting questions! I don't really know the answers. I found this in the Windows 95 Resource Kit (part 5 chapter 20):

Windows 95 provides floppy disk controller support as a 32-bit device driver, and offers improved performance for file I/O to floppy disk drives, plus improved reliability of the system. You can now format a disk or copy files to and from a disk while performing other tasks.

This somewhat confirms my suspicion about what the performance impact might be: I suspect that input and output to the floppy might not be much slower in 16-bit mode because the device is so slow, but I suspect that you won't be able to do anything else on your computer during the I/O. For example I suspect it might take about the same amount of time to format a floppy, but that instead of being able to do that in the background, you can't do anything else while it's running.

As for changing over to 16-bit mode, I couldn't easily find information about how to do that. It seems to me like the kind of thing that Windows Setup would arrange for you if you already had the 1 6-bit drivers installed when you installed Windows, as I think that is what happened when I first installed Windows 95 and needed a 16-bit CD-ROM driver. https://www.betaarchive.com/wiki/index.php/Mi … _Archive/131499 talks about 16-bit CD-ROM drivers and it just says to use them, it doesn't say you need to do anything special, so maybe you can just add the 2M driver to CONFIG.SYS and Windows will pick it up.

Okay. Thank you. 🙁