Generic MS-DOS 2.11 for Windows 1.x

[Lucas Brooks]

Since everyone suddenly became interested in installing early Windows 1.x pre-releases again recently, I have seen a number of people getting confused about which MS-DOS 2.x OEM to choose. I can see that most people are use the AT&T or Toshiba OEM on VMware for no real reason apart from "it works". I actually suggest using IBM PC-DOS because Microsoft used it to compile and run Windows 1.x but since most people (including myself) prefer MS-DOS over IBM PC-DOS, I decided to make a generic MS-DOS 2.11 that should work on all PC-compatible hardware, emulators and hypervisors. I actually did this ages ago and it was on my HDD until I dug it up quite recently. If I recall correctly, I compared all MS-DOS 2.11 releases we currently have and picked out all original Microsoft files.

The good thing about this is you can simply run FDISK and FORMAT without restarting so you can start with a new VM, install and boot Windows 1.x without needing to restart (so it is possible to write a batch file that installs both DOS and Windows). I decided to put it here rather than in the offer/request section because it is not something official although it is more "Microsoft" than any OEM release.

Download: https://mega.nz/file/YEVDwAzR#3yH_HwSdF ... B3QgT7fG9c

[xelloss]

The good thing about this is you can simply run FDISK and FORMAT without restarting

Hmm? Do you mean this version of DOS can reload the partition table and reassign drive letters without rebooting?

[msdos6000]

It is not working, as guess what... (VMware)
Good old invalid code being executed or screwed up hard drive! (https://forum.winworldpc.com/discussion ... ent_167558)

[Lucas Brooks]

Then something screwed up on your side. It works perfectly fine on VMware for me (I used it for my Windows 1.0 Alpha Release VM). If you don't see the invalid disk message, then probably something happened before it even got to the boot sector (or everything worked but DOS BIOS screwed up).

Hmm? Do you mean this version of DOS can reload the partition table and reassign drive letters without rebooting?

I think early DOSes can. Not sure about PC-DOS though.

[msdos6000]

Oh, it turns out I am a complete idiot. It works with the SCSI hard disk type, in fact, some pictures:


Update:
I'm pretty sure it was assumptions with hardware. In fact:

[Lucas Brooks]

Since Microsoft did not ship any good OEM Format modules (the generic one can only clear FAT and zero root directory) with the OAK, I have unlinked FORMAT.COM (from my generic MS-DOS 2.11) into 3 object files to help you with customizing DOS. You can download them here.

I have of course fully reversed FORMAT.COM and wrote my semi-working OEM Format Module (for both MS-DOS 2.00 and MS-DOS 2.11) based on that, but I can't really share it because it differs slightly to the code Microsoft published and the OEM module (OEMFOR.ASM) was written by an OEM.

If you would like to start writing your own OEM module, I suggest basing it off GENFOR.ASM from MS-DOS 2.00 OAK and disassemble OEMFOR.OBJ to get an idea of what a fully functional OEM module should look like.

[msdos6000]

This is atleast COMMAND.COM compatible with the ms-dos source code. (https://www.pcjs.org/blog/2018/11/21/?multiplier=4287). I modified command.com from the ms-dos source code and built it, and placed it on the disk. Below is my modified version (Bootable)

https://mega.nz/file/7ptAGaRK#_VzuDQWR1 ... 2492pzcO6k

[Lucas Brooks]

I managed to build the entire source tree before but it does not produce identical results because the source code was modified by TeleVideo. I once worked on fixing the code to produce binary-identical files but gave up after getting to COMMAND.COM (or MSDOS.SYS, can't remember). Basically have to turn all IBM switches off because for some stupid reasons, OEMs loved to use the IBM version.

All files built from the MS-DOS 2.11 source code released by Microsoft should not be considered as original because TeleVideo modified almost all files. If you assemble COMMAND.COM with IBM switch on, you'll be greeted by the TeleVideo copyright. Maybe I did restore COMMAND.COM source code and built the COMMAND.COM (in my generic MS-DOS 2.11) with it but I can't really remember. COMMAND.COM build using Microsoft's released code is definitely not original.