John Elliott uploaded a second folder yesterday containing the 2.11 kernel. I rolled it with both 5.1A and 4.0, using the actual EXE2BIN from the source distribution, and either the LINK from the DOS 3.3 OAK or the one from Visual Basic for MS-DOS. I’ve also rolled COMMAND.COM. Plug in the PC DOS 2.1 IBMBIO.COM and bootloader – and yes, it works. I’ve never stresstested the thing but it absolutely works.

I have built it on freedos using the masm and link in masm 5.1 and the exe2bin that comes with freedos 1.2.

I was able to replace the ibmdos.com on a pc-dos 2.10 disk with the msdos.sys file I compiled, boot it successfully and run several of the programs on the disk except for basic and basica. Pretty soon it stopped recognizing the floppy it booted from, though.

This is on 86box.

Rolled it with MASM 5.10A, LINK 5.31.009 from Visual Basic for MS-DOS, and a self-rolled EXE2BIN from the DOS 2 tree. Spits a few warnings, but it rolls, and works with the PC DOS 2.0 bootloader and DOS BIOS.

I wonder what differences in COMMAND.COM 2.11 vs. the prior 2.02 prevent it from being used with a 2.00 kernel.

The LINK I mainly used was version 5.60.339 from Visual C++ 1.52, though LINK 2.40 also seems to work.

At least it’s possible to test msdos.sys with the bootstrap and ibmbio.com from PC DOS 2.10 (something I’ve done for years).

DOS 3.0 was the first to fill in the data used to construct argv[0] in C applications, meaning that applications which need this information cannot run under 2.x. (I have just confirmed this; I thought it was 3.1.)

Yes I have a chunk of MS-DOS.sys built, but it is missing parts. Just as one of the ASM files is incomplete, and all the high level text Io is missing. I think the link script is for 2.00 which is why the macros are in place for a 2.00 build, lacking internationalisation support.

It’ll take a bit of filling in the missing bits to get it complete.

On the other side of the chain, I’m wondering why any DPMI stuff couldn’t run with DOS 2…

I found out what amount of MS-DOS 2.11 I’d actually built while trying to find another copy of the command.com sources. Unfortunately, MSDOS.SYS wasn’t part of it (guess I had given up due to the link issues).

I had built chkdsk, command, debug, diskcopy, edlin, exe2bin, fc, find, format, more, print, recover, sort and sys. I think that’s a pretty big chunk.

In the 2.11 case, Tandy made a few interesting tweaks. Like, there’s support for the @ metacommand in batch files (which normally doesn’t exist prior to 3.3).

2.11 is more source, although it’s damaged/incomplete. There is source to the platform code on bitsavers for the Seattle Computer Products Gazelle of all things. But it’s version 2.00, not 2.11

DOS/Command won’t be in any OAK as the OEM shouldn’t be messing with the actual OS.