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The precursor of MSDOS wasn't much better than CP/M. Gates hired J. Gordon Letwin away from Heathkit where he authored most of HDOS (Heathkit DOS). Letwin incorporated the loadable device driver from HDOS into the new MSDOS to make it more flexible than CP/M. Microsoft also licensed System 7 UNIX from Western Electric. That became the baseline for their Xenix product on the Tandy/Radio Shack TRS-80 Model 16 (68000). Letwin incorporated the tree structured filesystem of UNIX into MSDOS, but bastardized the slash/backslash orientation to pretend it was "different".

I recognize much of the technology snitched from HDOS and UNIX as I've had full source code to both since 1980.

> The precursor of MSDOS... Letwin incorporated the tree structured filesystem of UNIX into MSDOS, but bastardized the slash/backslash orientation to pretend it was "different".

Ummm, nope. Microsoft adopted backslash for the directory separator because the UNIX forward slash directory separator was already in use as a switch character in CP/M (and every DEC OS: RT-11, RSX-11, VMS) and to retain command-line compatibility with CP/M it was necessary to retain the forward slash for switches -- for the user, anyway (the OS itself wouldn't care, of course).

The obvious and correct choice for switch character would be the dash (hyphen) used in UNIX, right? And the UNIX forward slash for directory separator, right? Well, guess what...

1. The ONLY place where the backslash is required for directories -- to this day in Windows -- is in the user interface. All places in the BIOS and operating system calls (e.g. INT 21), either forward slash or backslash are valid as directory separator.

2. In versions of DOS prior to 5.0, you could set an environment variable called "SWITCHAR" which would be interpreted as the switch character. That is, if you

set SWITCHAR=-

you could use UNIX '-' for the switch character on all COMMAND.COM commands. DOS function 3700 allowed a program to query the SWITCHAR to interpret the passed commandline.

Unfortunately, SWITCHAR didn't gain wide acceptance except among (us) UNIX programmers who were forced to deal with MS-DOS, and it was eventually dropped. But it was there.

Anyway, the backslash wasn't chosen "to pretend it was different", it was because they HAD to be different, if they were to retain CP/M compatibility on the command-line.

And with regard to "bastardized" -- you are exactly right!