MS-DOS 3.20 (07-07-1986) problem on early IBM PC 5150
I figured out that MS-DOS 3.20 (07-07-1986) doesn't boot on IBM PC 5150 correctly (BIOS rev.1 -- 04/24/1981 , BIOS rev.2 -- 10/19/1981) with 128KB or higher RAM
But IBM PC-DOS 3.20 (12-30-1985) has no problem on its machine
This problem is only with MS-DOS 3.20 (07-07-1986).
MS-DOS 3.21 (05-01-1987) seems to be fixed this problem.
Anyway, MS-DOS 3.20 (07-07-1986) is only version which doesn't work on IBM PC 5150 rev.1/rev.2
But IBM PC-DOS 3.20 (12-30-1985) has no problem on its machine
This problem is only with MS-DOS 3.20 (07-07-1986).
MS-DOS 3.21 (05-01-1987) seems to be fixed this problem.
Anyway, MS-DOS 3.20 (07-07-1986) is only version which doesn't work on IBM PC 5150 rev.1/rev.2
Comments
Is the problem specific to the BIOS?
It is not too surprising they would have missed that, as most serious users probably upgraded to rev 3 in order to use expansion cards with ROM extensions.
Of course it is Not suprising issue, but I report the fact.
This result is from Microsoft MS-DOS 3.20 Genuine.
If this were from OEM vendor or modified DOS, I wouldn't report this fact.
I think this is Microsoft's problem because this was solved from DOS 3.21.
http://www.pcjs.org/disks/pc/dos/microsoft/3.20/
This issue is reported on PCjs.