It did, and also up till 3.0 (thus 2.10 and 2.11) had also SWITCHAR which you could change command options character / to - like in it was in UNIX convention, from CONFIG.SYS definition.

The problem with changing / to - was, that under MS-DOS command line parsing was left completely to a a loaded program, which then would had to know how to find out this change and act accordingly. And if not only MS-DOS std. utilities behaved properly and others not so much. Thus causing confusion which perhaps then lead to dropping that feature 3.0 onwards.

I think it was also before 2.0 or at least what delivered with Apricot PC (UK made PC) 1.25 which I tinkered with few days as we had it on display from Finnish importer ARAIC Rautakirja Oy (Finnish railways VR magazines and other related travel reading importer, also keeper of the R-kiosks). A very nicely built non IBM PC compatible PC with good graphics and then uncommon 3.5" 70kb disk drives before Apple Macintosh made the more popular.

https://www.homecomputermuseum.nl/en/collectie/act-computers...

e: Now did it change also path separator from \ to / ? It may have done it also. I bit later work more with Xenix and can't remember for sure. Starting from 286 versions SvR2.x, 386 SvR3.x up till SCO UNIX SVR4 early 90's and less with MS-DOS besides maintaining couple of TSR's I had written and just checked every MS-DOS release that those still did work.

Thankfully they ditched it. One of the best things about DOS was that it gave users control over the directory structure. While other OS's just barfed a billions directories all over your disk on install and spewed system files wherever they felt like it, DOS let you decide where you wanted things with the exception of a couple of files in the root directory. This did mean that some people just dumped everything into the root of their system drive, but everyone else could organize things however they wanted. You could learn a lot about someone, and their system, with a single dir command.

A lot of early dos development was trying to see how many unix concepts they could fit, directories, pipes, environment, devices.

Xenix was targeted at a hardware spec that was well out of reach for the ordinary home PC consumer. The amount of ram and HDD needed to install and run it would make a computer in 1985/1986 money equivalent to a $12,000 desktop today. They always knew they needed to keep developing DOS for the low end.

The easy way to write assembler for a machine with no compilers is to write the code in C, get the algorithm right, then translate it to asm.

CP/M showed a lot of similarities to DEC's RT-11.

> the Unix path separator.

Using the backslash: one of those incredibly idiotic things that caused untold misery and time waste further down the road. Future generations cursed the day.

I love that for the next few years they were commonly called Winchester drives due to IBM's original naming in the early 70's.

2BSD is still hanging on getting updates and forked projects to this day. My understanding is that it's longevity in the face of the existence of 4bsd is because it is 16-bit clean, These days it is mainly for people who want a unix for their microcontroller.

Here is one, https://github.com/RetroBSD/retrobsd. This is for the pic32, so I may be wrong about the 16-bit thing.

I don't know if anyone has done it but it looks like it could fit, perhaps not on a original 8086 PC, but perhaps a 286 with 640K.

Yes, memory was the main issue. The PC launched with 64KB of RAM. Technically there was a model with 16KB of RAM and no disk drive but I don't think they produced or sold many of those.