Hi! I don't think MS-DOS 5 itself is the problem.
Like MS-DOS 6.xx, it's quite compatible to MS-DOS 3.x, also because it uses the same kernal type (MS-DOS 4 was different).

I guess it has to do with the floppy format, number of tracks per sector (8 vs 9) or something.

Or, it's somehow related to the boot loader routine, maybe.
Early DOSes had the ability to load the core system files into memory within a single pass.
That's because they fitted into a single storage unit on floppy.

SpectriaForce wrote on 2022-08-03, 12:22:

I've tried booting from a MS-DOS 5 setup disk (an original 360K one) on a IBM PC Portable in the past. If I remember correctly it didn't boot, but it did boot from a IBM DOS 3.2 startup disk. I wonder whether the BIOS revisions have anything to do with that? Are there IBM BIOS versions of the IBM PC that don't work with MS-DOS 5? I couldn't really find any info about this Googling around.

Just an idea, the setup of MS-DOS 5 requires more that 256K RAM which is the standard amount of the IBM PC portable (I believe it needs 384 or 512KB). If the RAM was not expanded that might well be the reason. It should boot from a DOS 5 start up disk though, just not the setup disk.

konc wrote on 2022-08-06, 14:25:

SpectriaForce wrote on 2022-08-03, 12:22:

I've tried booting from a MS-DOS 5 setup disk (an original 360K one) on a IBM PC Portable in the past. If I remember correctly it didn't boot, but it did boot from a IBM DOS 3.2 startup disk. I wonder whether the BIOS revisions have anything to do with that? Are there IBM BIOS versions of the IBM PC that don't work with MS-DOS 5? I couldn't really find any info about this Googling around.

Just an idea, the setup of MS-DOS 5 requires more that 256K RAM which is the standard amount of the IBM PC portable (I believe it needs 384 or 512KB). If the RAM was not expanded that might well be the reason. It should boot from a DOS 5 start up disk though, just not the setup disk.

First disk of MS-DOS 5 is called setup, not start up nor install like MS-DOS 4:

Correct me if I'm wrong.

It's unfortunate that I don't have an IBM PC anymore, but I would definitely like to experiment to see what the problem is.

SpectriaForce wrote on 2022-08-06, 18:34:

First disk of MS-DOS 5 is called setup, not start up nor install like MS-DOS 4:

DOS 5 has an autoexec.bat that launches the setup program, and unlike 6, there aren't any keys you can push or hold down to bypass that. You have to wait for it to launch and then F3 to get out. So to debug further it'd really depend on whether it just hangs silently with a blinking cursor, shows an error message, etc.
I'm not familiar with DOS 4; too young and always understood it to be the Windows Vista/8 of its time 😁
I suppose you could play with PCem and different BIOSes/memory sizes to see if you can reproduce the issue.

konc wrote on 2022-08-06, 14:25:

SpectriaForce wrote on 2022-08-03, 12:22:

I've tried booting from a MS-DOS 5 setup disk (an original 360K one) on a IBM PC Portable in the past. If I remember correctly it didn't boot, but it did boot from a IBM DOS 3.2 startup disk. I wonder whether the BIOS revisions have anything to do with that? Are there IBM BIOS versions of the IBM PC that don't work with MS-DOS 5? I couldn't really find any info about this Googling around.

Just an idea, the setup of MS-DOS 5 requires more that 256K RAM which is the standard amount of the IBM PC portable (I believe it needs 384 or 512KB). If the RAM was not expanded that might well be the reason. It should boot from a DOS 5 start up disk though, just not the setup disk.

Hi there! Perhaps that's right in general,
but I've run MS-DOS 6.20 on a 286 motherboard (full AT) with a ceramic CPU
and 256KB DIP RAM (on board) in the past..
It was a custom bootable floppy, though.

SpectriaForce wrote on 2022-08-06, 18:34:

First disk of MS-DOS 5 is called setup, not start up nor install like MS-DOS 4:

Jo22 wrote on 2022-08-06, 19:53:

Hi there! Perhaps that's right in general, but I've run MS-DOS 6.20 on a 286 motherboard (full AT) with a ceramic CPU and 256KB […]
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Hi there! Perhaps that's right in general,
but I've run MS-DOS 6.20 on a 286 motherboard (full AT) with a ceramic CPU
and 256KB DIP RAM (on board) in the past..
It was a custom bootable floppy, though.

The "setup" disk will run the installation program automatically. This won't succeed on a PC with 256KB RAM, which is the default amount an IBM PC portable has.
I call "start up" disk a disk created with format /s or sys, which only boots to the prompt. Such a disk should work, as Jo22 says too.

There are a few version of MS Dos 5.00. The original release which had some hickups and MS Dos 5a with these bugs cleaned up.

MarkP wrote on 2022-08-07, 09:31:

There are a few version of MS Dos 5.00. The original release which had some hickups and MS Dos 5a with these bugs cleaned up.

+1
I second that.

There were at least two versions of MS-DOS 5!

The exact revision can be checked with VER /R

It was common knowledge at the time.

I went the DRDos 6 route with far more features.

Jo22 wrote on 2022-08-07, 17:30:

+1 I second that. […]
Show full quote

+1
I second that.

There were at least two versions of MS-DOS 5!

The exact revision can be checked with VER /R

"Formatting 3260M" in MS-DOS 5.00 ?
But how?
Sectors larger than 512 Bytes?

Grzyb wrote on 2022-08-08, 14:10:

"Formatting 3260M" in MS-DOS 5.00 ? But how? Sectors larger than 512 Bytes? […]
Show full quote

Jo22 wrote on 2022-08-07, 17:30:

+1 I second that. […]
Show full quote

+1
I second that.

There were at least two versions of MS-DOS 5!

The exact revision can be checked with VER /R

"Formatting 3260M" in MS-DOS 5.00 ?
But how?
Sectors larger than 512 Bytes?

Magic wand maybe.

It's been a while.. There's a patch for that.
Technically, that should also work with MS-DOS 6.xx, but that didn't exist at the time yet,
so things must be done manually via hex editor.

Re: Browsing a harddisk under DOS without using BIOS routines (INT13H)

Short explanation:
Re: HDD recognition issues.

Edit: Speaking of the hang of MS-DOS 5 on the IBM..
It seems to happen with MS-DOS 6.22, too.

Maybe it's really the setup program.
Renaming autoexec.bat to autoexec.bak or editing it should stop making setup run automatically.

Alternatively, it's possible to press F5 during boot or to press CTRL-C, to aboard loading stuff.
The F5 thing may already work in DOS 5 ?, but not F8 (single-stepping through autoexec.bat/config.sys).

https://forum.vcfed.org/index.php?threads/ms- … -xt-5160.33931/

Edit: I forgot to mention.. MS-DOS 6.22 itself does work fine on an 8088/XT PC.
I've been using it for years on my XT compatible.
And the PC/XT emulator PCE did use MS-DOS 5, too.

DOS 5.0 came with the First 486 computer I purchased back in 1993
Worked fine.

I would say go threw the install process and reboot.
It it does not boot try to SYS the C:

# A:\SYS C:
Reboot