github.com/Microsoft/MS-DOS/tr

"The user manual contains some significant errors. Most of these are due to last minute changes to achieve a greater degree of compatibility with IBM's implementation of MS-DOS (PC DOS). This includes the use
of "\" instead of "/" as the path separator, and "/" instead of "-"
as the switch character."

it's always kind of interesting when you encounter a fossil trace of someone's Giant Mistake as it happened.

@brennen The weird thing about this is that "/" was the switch character on RT-11, which CP/M imitated (including using "/" as the switch character in PIP.COM), and MS-DOS 1.0 was a carbon copy of CP/M (though I don't remember if it had PIP).

@kragen @brennen There's a reason why MS-DOS 2.0 specifically was planned to use / as the path separator and - as the switch, though.

MS-DOS 1.x was absolutely a CP/M clone, but MS-DOS 2.0 was intended to be something entirely different - the eventual goal was to turn MS-DOS into a single-user, single-tasking Unixlike, with Xenix binary compatibility (much like the goal of Heinz Lycklama's Version 6 Unix-derived LSX).

Obviously things did not ultimately go that direction, but a fair amount of Unix semantics made it into MS-DOS as a result anyway.

@bhtooefr @kragen @brennen
This is something I hadn't heard!

I knew that directories were one of several features Microsoft added that were taken from UNIX, & that Microsoft's status as a UNIX vendor at the time was related, but I was unaware of any plan to make them actually binary-compatible! That would have been a very interesting system.

Was Xenix even using 16 bit words? Unix on micros usually had 18-bit words, right?

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Eldritch Café

Une instance se voulant accueillante pour les personnes queers, féministes et anarchistes ainsi que pour leurs sympathisant·e·s. Nous sommes principalement francophones, mais vous êtes les bienvenu·e·s quelle que soit votre langue.

A welcoming instance for queer, feminist and anarchist people as well as their sympathizers. We are mainly French-speaking people, but you are welcome whatever your language might be.