Perhaps the earliest ancestor of Microsoft DOS and Windows just arrived on the Internet

Earlier today, we covered a cool software utility program dubbed "MSbob" that tries to take inspiration from the failed Microsoft Bob project. While the app may be of limited use in its current state, it still helped refresh the memory of a bygone Windows era.

Before Windows though, and its familiar and beloved graphical user interface (GUI), there was DOS (Disk Operating System). In case you may not be aware, MS-DOS - which was earlier known as PC DOS, as the OS was developed for IBM PC - was not an in-house creation of Microsoft and it was based on 86-DOS.

Very early 86-DOS operating system alongside its disk

86-DOS was also referred to as QDOS (short for Quick and Dirty Operating System). The "86" if you haven't guessed takes inspiration from the Intel 8086 processor nomenclature as the 86-DOS operating system was developed by Seattle Computer Products (SCP) for its Intel 8086-based S-100 computer kits. While Seattle Computer Products went for the 8086, IBM, instead, chose the 8088 variant.

A couple of days ago, X (Twitter) user and Windows enthusiast NTDEV spotted that the earliest known versions of 86-DOS were uploaded to the Internet Archive, by another user f15sim. The version in question is 0.11, and a photo of its accompanying disk was uploaded for preservation as well.

NTDEV took a look at the 86-DOS 1.1 on Open SIMH (History Simulator) and noted the presence of nine files in this ancient piece of software, with one of those, interestingly, being a chess simulator.

Files inside 86-DOS early version

RDCPM: a copy (?) utility, probably related to CP/M

HEX2BIN: a development utility which, according to the developer of 86DOS, Tim Patterson, "had all the basic utilities for assembly-language development except an editor"

ASM: an 8086 assembler originally written in Z80 ASM

TRANS: a Z80 to 8086 translator

SYS: probably a utility to write the command interpreter to a new floppy (similar to how early MS-DOS versions used to do)

EDLIN: the line editor included in MS-DOS, here at its humble roots.