IMHO SvarDOS is way better, than FreeDOS. As for compatibility... m$-DOS 6.22 for pre-386 CPU based systems, and 7.10 (or even ROM-DOS 7.10) for 386 and newer. PC-DOS 2000 (7.0 rev.1) is also good alternative to m$-DOS 7.10.

I will say that although I use DOS 7.1 on all my 32 bit machines, if the machine is 16 bit I use DOS 5.0. DOS 7.1 won't even boot on a 16 bit machine.

I think I might have a couple of machines that I put DOS 3.3 on though.

The real advantages or disadvantages for older machines like that have to do with the utilities. EDIT is nice to have.

MS-DOS 6.22 for most things before Win9x. For Win9x, the DOS that comes with it.

FreeDOS has too many issues with stuff that makes it too much of a headache to work with retro hardware.

Most people have forgotten this, but MS-DOS 6.22 was available for free via the MS ftp site as well as a host of other things before they took the ftp down.

appiah4 wrote on 2026-06-09, 13:02:

theelf wrote on 2026-06-09, 12:58:

PC-DOS 7.1, same compatibility MSDOS, FAT32 support even on 286 machines (maybe 8088 but never tested FAT32), very VERY reduced memory needs

Exelent DOS

Hello, fellow man of culture.

Gang PC-DOS

I generally use version 7 unless I need FAT32. The reduced memory use applies not only to the kernel, but also most of the commonly used installable device drivers. Vernon did a great job optimizing it.

cyclone3d wrote on 2026-06-09, 16:20:

Most people have forgotten this, but MS-DOS 6.22 was available for free via the MS ftp site as well as a host of other things before they took the ftp down.

I recall the 6-to-6.22 "StepUp" upgrade being there, but not the full version.

jakethompson1 wrote on 2026-06-09, 17:19:

cyclone3d wrote on 2026-06-09, 16:20:

Most people have forgotten this, but MS-DOS 6.22 was available for free via the MS ftp site as well as a host of other things before they took the ftp down.

I recall the 6-to-6.22 "StepUp" upgrade being there, but not the full version.

That is my recollection also, you had to have 6.0 already. Some folks claimed it worked on 5, but IDK if that was the download version or something they got from their OEM.

theelf wrote on 2026-06-09, 12:58:

PC-DOS 7.1, same compatibility MSDOS, FAT32 support even on 286 machines (maybe 8088 but never tested FAT32), very VERY reduced memory needs

Exelent DOS

But can it run Windows 3.x with FAT32 ?

MS-DOS 7.10 patched with 3XSTART can do it - there are certain limitations, but nothing serious.

Grzyb wrote on 2026-06-09, 19:02:

theelf wrote on 2026-06-09, 12:58:

PC-DOS 7.1, same compatibility MSDOS, FAT32 support even on 286 machines (maybe 8088 but never tested FAT32), very VERY reduced memory needs

Exelent DOS

But can it run Windows 3.x with FAT32 ?

MS-DOS 7.10 patched with 3XSTART can do it - there are certain limitations, but nothing serious.

yes, win3x work perfect with fat32, tested in both my DOS computers using PC-DOS 7.1+FAT32, a 286 and a 486DLC

No need to patch anything, but this patch (second one) is recommended, Making Windows 3.11 work in DOS7.10 (patches inside)

Anyways in years of using FAT32+win3.x on PC-DOS never have any corrution problem

Love my 286 with a 32GB CF Card... plenty of space!!

theelf wrote on 2026-06-09, 20:26:

yes, win3x work perfect with fat32, tested in both my DOS computers using PC-DOS 7.1+FAT32, a 286 and a 486DLC

No need to patch anything, but this patch (second one) is recommended, Making Windows 3.11 work in DOS7.10 (patches inside)

Anyways in years of using FAT32+win3.x on PC-DOS never have any corrution problem

I'm confused, probably because of this failure report - 3xStart for FAT32 for IBM PC DOS v7.1? (No IO.SYS to modify, has IBMBIO.COM and IBMDOS.COM)

Love my 286 with a 32GB CF Card... plenty of space!!

Nice, you definitely make a good use of that machine - Re: Video playback on a 286? - here's how to do it

But I'm wondering about one thing...
For >8 GB you need INT 13h extensions, right?
Is there some BIOS/driver which provides INT 13h extensions on a 286 ?

Some older versions of Ontrack's DDO exist for 286s.

wierd_w wrote on 2026-06-09, 22:43:

Some older versions of Ontrack's DDO exist for 286s.

But what version exactly?
I would expect early Ontrack DDO versions only overcome the 528 MB limit.
For overcoming the 8.4 GB limit, INT 13h Extensions are necessary - when were they first implemented? 1995, or even later? Are there any 286-compatible implementations?

Grzyb wrote on 2026-06-09, 23:06:

But what version exactly? I would expect early Ontrack DDO versions only overcome the 528 MB limit. For overcoming the 8.4 GB li […]
Show full quote

wierd_w wrote on 2026-06-09, 22:43:

Some older versions of Ontrack's DDO exist for 286s.

But what version exactly?
I would expect early Ontrack DDO versions only overcome the 528 MB limit.
For overcoming the 8.4 GB limit, INT 13h Extensions are necessary - when were they first implemented? 1995, or even later? Are there any 286-compatible implementations?

Digging around, I see that Ontrack Disk Manager 5.00a was released in 1992, which still had 286s limping around.
It has support for int13h extensions for cyl counts greater than 1024.

Unsure just how far you can push it, but that should get you over the 504mb hump at least.

More digging, version 6.xx is the first versions to support LBA. It mentions 486s in the readme. It is unknown if it will work on a 286. It released in 1994.

It has support for int13h extensions for cyl counts greater than 1024.

Cool, but let's please keep in mind that classic MS-DOS (5/6) uses standard int13h interface and has a 1024 cylinder limit.
It can handle 1024 cyls (0-1023) and and 255 heads (0-254) and 63 sec out of box.

http://www.steunebrink.info/bioslim.htm
https://msfn.org/board/topic/159631-testing-m … os-limitations/

There's a patch for MS-DOS 5 that allows going past 1024 cylinders (via normal int13h interface). Works for Virtual PC 2007, for example.
Re: Browsing a harddisk under DOS without using BIOS routines (INT13H)
Re: Intel VS440FX refuses to boot DOS 6.22 from detected SSD

That being said, DOS 7.1 is LBA-aware and might support extended int13h interface (not the be confused with normal int13h interface).
But only a few LBA DOSes run on an 80286 CPU, IBM DOS 7.1 being one of it.
MS-DOS 7.x drops an error message saying that it needs an 386 or better.

Edited. Edited.

Grzyb wrote on 2026-06-09, 22:17:

theelf wrote on 2026-06-09, 20:26:

yes, win3x work perfect with fat32, tested in both my DOS computers using PC-DOS 7.1+FAT32, a 286 and a 486DLC

No need to patch anything, but this patch (second one) is recommended, Making Windows 3.11 work in DOS7.10 (patches inside)

Anyways in years of using FAT32+win3.x on PC-DOS never have any corrution problem

I'm confused, probably because of this failure report - 3xStart for FAT32 for IBM PC DOS v7.1? (No IO.SYS to modify, has IBMBIO.COM and IBMDOS.COM)

Perhaps one would have to test manually. I haven't tested it myself as I exclusively use a patched MS-DOS 7.10 (Win98SE) kernel for Win3.1x usage.

A good part for PC-DOS 7.1, however, is that it won't trip Win9x checks in some programs that would otherwise get tripped when using MS-DOS 7.10 (Win98SE), namely Creative (SB16) DOS/Win3.x drivers' install program.

A good part for PC-DOS 7.1, however, is that it won't trip Win9x checks in some programs that would otherwise get tripped when using MS-DOS 7.10 (Win98SE), namely Creative (SB16) DOS/Win3.x drivers' install program.

That makes sense, both have a different vendor ID (OEM number).
MS-DOS has FFh, while IBM DOS has 00h, I think.
MSD can show it, for example.

Info: https://pcdosretro.gitlab.io/dosver.htm

AFAIK PC-DOS 7.1 was freely available for download from IBM/Lenovo's servers as part of IBM ServerGuide Scripting Toolkit, but it is not a full DOS version. Can it be combined with the files from PC-DOS 7.0 rev.1 (2000) like an update?

aVd wrote on 2026-06-10, 04:07:

AFAIK PC-DOS 7.1 was freely available for download from IBM/Lenovo's servers as part of IBM ServerGuide Scripting Toolkit, but it is not a full DOS version. Can it be combined with the files from PC-DOS 7.0 rev.1 (2000) like an update?

Yes you can. Most of the stuffs from older PC-DOS will work.

PC-DOS 7.1 is compatible with older PC-DOS' boot sectors, provided you overwrite the original IBMBIO.COM and IBMDOS.COM.

You can also use lDebug's boot mode to launch the PC-DOS 7.1 kernel. The lDebug boot sector can be chainloaded by NTLDR or GRUB4DOS.

LSS10999 wrote on 2026-06-10, 04:17:

Yes you can. Most of the stuffs from older PC-DOS will work.

PC-DOS 7.1 is compatible with older PC-DOS' boot sectors, provided you overwrite the original IBMBIO.COM and IBMDOS.COM.

You can also use lDebug's boot mode to launch the PC-DOS 7.1 kernel. The lDebug boot sector can be chainloaded by NTLDR or GRUB4DOS.

Ok, so I can borrow the missing files from PC-DOS 7.0 (2000), but why do I need to do something with the boot sector? There are FDISK32.COM and FORMAT32.COM in PC-DOS 7.1. Is there a problem with SYS.COM from PC-DOS 7.1 on FAT32 formatted partitions/drives?

aVd wrote on 2026-06-10, 04:50:

LSS10999 wrote on 2026-06-10, 04:17:

Yes you can. Most of the stuffs from older PC-DOS will work.

PC-DOS 7.1 is compatible with older PC-DOS' boot sectors, provided you overwrite the original IBMBIO.COM and IBMDOS.COM.

You can also use lDebug's boot mode to launch the PC-DOS 7.1 kernel. The lDebug boot sector can be chainloaded by NTLDR or GRUB4DOS.

Ok, so I can borrow the missing files from PC-DOS 7.0 (2000), but why do I need to do something with the boot sector? There are FDISK32.COM and FORMAT32.COM in PC-DOS 7.1. Is there a problem with SYS.COM from PC-DOS 7.1 on FAT32 formatted partitions/drives?

I've made a thread with all the info I could get about PC-DOS 7.1 before.

If you keep your system partition as FAT16, then PC-DOS 7.1 will still boot with the old boot sector you made when installing PC-DOS 7.0. Converting it to FAT32 will break it.

There are some limitations with those FAT32 utilities from PC-DOS 7.1:
- FORMAT32.COM can only create a FAT32 filesystem up to 8GB from what I tested, even though your partition may be larger.
- SYS.COM is actually the one from PC-DOS 7.0 which cannot be used with PC-DOS 7.1 (Incorrect DOS version).
- FORMAT32's /S option does not depend on SYS.COM, but it has some quirks requiring two consecutive runs to properly set up a bootable PC-DOS 7.1 partition. First FORMAT32 /Q then FORMAT32 /Q /S.

Best versions of MS-DOS so far: 3.31*, 5.0, 5.0a, 5.02, 6, 6.2, 6.21 and 6.22
Mediocre versions of MS-DOS: 3.3 (and earlier), 4.0 and 4.01

MS-DOS 3.31 was not a retail release and was only available to Compaq OEM computers; the OS supported hard disks up to 512 MB. MS-DOS 4.0 and 4.01 supported hard disks partitions up to 2 GB and whole hard disks up to 4 GB. MS-DOS was memory hungry and even had a bug that could not properly recognise whole hard disks larger than 4 GB. MS-DOS 5.0 through 6.22 supported hard disks up to 1,023 cylinders, 255 heads and 63 sectors per track for a total of 7.84 GB.

MS-DOS and PC-DOS 4.0, 4.01, and 5.0 all had a serious bug where CHKDSK and UNDELETE can corrupt data on a logical partition! if the file allocation table (FAT) of a disk uses 256 sectors and the cluster capacity is between 65,278 to 65,510. If you run CHKDSK /F on a FAT-formatted logical partition by answering N (no) to the question "Convert lost chains to files?", CHKDSK writes 256 copies of your FAT onto the disk - overwriting the entire directory structure. In MS-DOS and PC-DOS 5.0, running UNDELETE causes unpredictable results.

This bug has no effect on primary partitions.

The CHKDSK and UNDELETE bugs were fixed in MS-DOS and PC-DOS 5.0a.