I have used FreeDOS a few times too and only issue I had was with PAS16 and the old CDROM driver it used but it was on a Beta version from about 2001/2002.
Not sure if that issue still happens under the distributed releases....

A few years into the noughties, you started to see boards saying Win98 or higher required... this wasn't "we're only going to provide drivers for 98 up" this was MS-DOS 6.22, PC-DOS 7 etc will not boot on this system. I believe it was something to do with resource management and allocation and the low/UMB/high mem boundaries. The point I'm making is, FreeDOS isn't to blame, if unfree DOS doesn't work on the system either. However, I had heard there were efforts to work around these broken by design systems, so eventually, FreeDOS might be the only DOS that ever works with them.

EDIT: BTW I'm pretty sure Dell, IBM, HP/Compaq made sure that DOS continued to work on their business systems because there were still legacy business DOS applications that their big customers were using, still might be using even.

DOS 6.22 will boot on anything. Whether or not you get sound on it is another thing, and many modern video cards lack a few of the old VESA modes.

I would love to see a supposed list of older hardware (motherboards) that are confirmed to not work with DOS versions before Windows 98 DOS.

I wish I could remember more details was mentioned on the hardware sites in the day, can't think of search terms that get anything sensible out of google at the moment, it's getting worse. Not sure who it was that started it, Soyo or Shuttle maybe, there was some discontent about it, maybe market rejected those boards and nobody else did it until what's recently going on with secure boot etc.

I booted into DOS on accident once. I took the CF card out of my XT machine and put it into the USB reader on my Ryzen PC, and then the computer restarted after an update. It booted from the CF card instead of the HDD for some reason and there was the DOS prompt 🤣

BitWrangler wrote on 2021-07-17, 00:18:

A few years into the noughties, you started to see boards saying Win98 or higher required... this wasn't "we're only going to provide drivers for 98 up" this was MS-DOS 6.22, PC-DOS 7 etc will not boot on this system. I believe it was something to do with resource management and allocation and the low/UMB/high mem boundaries. The point I'm making is, FreeDOS isn't to blame, if unfree DOS doesn't work on the system either. However, I had heard there were efforts to work around these broken by design systems, so eventually, FreeDOS might be the only DOS that ever works with them.

EDIT: BTW I'm pretty sure Dell, IBM, HP/Compaq made sure that DOS continued to work on their business systems because there were still legacy business DOS applications that their big customers were using, still might be using even.

Unlikely, as you need a way to install windows 98 into said system and that includes booting DOS.
From what I remember you just couldn't get certain subsystems of the board to work.

Yeah maybe I'm stating it wrong, like DOS will boot, but you'd got no DMA in 16 bit mode

konc wrote on 2021-07-17, 06:51:

BitWrangler wrote on 2021-07-17, 00:18:

A few years into the noughties, you started to see boards saying Win98 or higher required... this wasn't "we're only going to provide drivers for 98 up" this was MS-DOS 6.22, PC-DOS 7 etc will not boot on this system. I believe it was something to do with resource management and allocation and the low/UMB/high mem boundaries. The point I'm making is, FreeDOS isn't to blame, if unfree DOS doesn't work on the system either. However, I had heard there were efforts to work around these broken by design systems, so eventually, FreeDOS might be the only DOS that ever works with them.

EDIT: BTW I'm pretty sure Dell, IBM, HP/Compaq made sure that DOS continued to work on their business systems because there were still legacy business DOS applications that their big customers were using, still might be using even.

Unlikely, as you need a way to install windows 98 into said system and that includes booting DOS.
From what I remember you just couldn't get certain subsystems of the board to work.

Hm. This reminds me of certain notebooks. Worked fine in Windows each, but in pure MS-DOS.. 😮

Btw, I remember that DELL included a copy of FreeDOS (a CD) at some point..
I suppose, to not violate the OEM agreement it had with Microsoft (PCs must not be sold without an OS).

No idea if that FreeDOS was ever meant to be used with those PCs, thus.
From what I can say, DELL PCs have the strangest BIOSes I've ever seen.

They are encrypted somehow and you need the official upgade tool, too.
Luckily, older versions of it are dual Windows/DOS executables, at least.

But still, being able to simply write a BIN file into a socketed FLASH ROM chip with my TL866 would be much nicer.
That whole annoying corporate fuss is just nasty. I'd rater play with open cards.

I take it there isn't much of an issue then.

Caluser2000 wrote on 2021-07-22, 05:32:

I take it there isn't much of an issue then.

It really depends, I guess.

The basic stuff might work on such PCs, ie. they can boot DOS and execute Windows 9x setup.
If that wasn't the case, it wouldn't be an IBM PC compatible PC, after all.

The "issues" might be related to buggy/missing PS/2 mouse emulation via USB, faulty ISA DMA in certain memory regions,
the inability to run EMM386 properly, because the region in 640KB to 1MB is write-protected or occupied by USB/ethernet controllers,
issues with floppy drives (ISA DMA is required for floppy drives) and so on.

Another example that comes to mind: LPT ports found on PCI cards are seldomly DOS compatible.
The reason is, that they don't have port adresses like 3BCh, 378h, 278h in ISA address space.
They rather use 9800h and other high addresses on PCI range.

No make them work in DOS, a TSR would be required, which is rarely provided.
So these cards are essentially usable in Windows 9x/NT only.
Ironically, the Windows 9x drivers do sometimes include the ability to "remap" them to classic i/o ports.
So someone has to run DOS programes on Windows 9x, in order to be able to use the LPT ports.

This is similar to the Sound Blaster emulation found in certain Windows 9x drivers for late 90s sound chips.
On PCs equipped with such sound chips, DOS games have to run on Windows, in order to have sound.

Later, VDMSound was born, which provided SB16 emulation for all Windows 2k/XP PCs (an Alpha for Win98 also exists).
Gratefully, Windows XP at least had SB2 emulation in NTVDM out-of-box.

What I mean to say: Some "legacy" free systems may indeed suffer compatibility issues in plain DOS, but work in Windows 9x.

I'd prefer real issues and not hypothetical ones in this thread thanks/