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- Hacker News
- >"But it soon became clear that IBM was committed to keeping DOS 2.0 as close as possible to the eight thousand bytes [8K] used by DOS 1.1, so as not to disrupt their existing user base. [...] The first version of MS-DOS 2.0 shipped with IBM PC XT as PC-DOS 2.0 on March 8, 1983. It required about 20 KB of RAM, far more than MS DOS 1.0, so both versions continued to be sold simultaneously for a while."
And that approximate doubling, in RAM requirements, year by year (compare to Moore's Law for hardware!) for Microsoft's OS'es, has got us, fellow students of computer history, to where we are today -- with Microsoft OS'es being the size that they are and requiring the RAM that they do!
And it all started with upgrading (or "upgrading", take your pick of term!) an 8KB OS to a 20KB OS! :-)
- >Even a scaled-down version of Unix was too demanding for the 8086 chip”.
Interesting. At my old job I got my hands on Wang IN/ix around 1985, a 16 bit UNIX.
It ran on an 8086 but needed 512k memory. It ran fine. I wonder if memory was the main issue ? But seems the issue was probably memory for IBM and MS
by jmclnx - 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.by Narishma
- 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.
by somat - I know this is software focused, but as much of the work done in DOS 2.0 was to support the introduction of hard disks, it would be worth mentioning what the hardware was in the PC/XT:
https://en.wikipedia.org/wiki/ST-506/ST-412
https://www.google.com/search?client=firefox-b-d&q=ST-212+ha...
by walrus01 - 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.by ColdStream
- This is enlightening. Growing up playing with Unix boxes (and XENIX, specifically, mostly writing shell scripts and playing in the filesystem) and programming MS-DOS in assembly I could often see strange parallels between how stuff worked in MS-DOS and his stuff was in Unix. I just assumed MSFT programmers had used Unix at some point and wanted to lift features and idioms from it to use in DOS. It never occurred to me, knowing XENIX was a MSFT-licensed Unic derivative, that there might be more direct inspiration in that vague Unix "flavor" in DOS.
I never did any CP/M programming, so the whole FCB-based file manipulation API in MS-dos just seemed like strange old cruft to me. Had I been exposed to CP/M the Unix inspiration behind the handle-based API would have been a lot more apparent. (I got in about the MS-DOS 3.3 timeframe...)
What a strange world it would have been in MSFT got IBM to buy into the Unix path separator.
by EvanAnderson - > 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.
by euroderf - CP/M showed a lot of similarities to DEC's RT-11.by WalterBright
- I was teaching myself 8086 16-bit assembly a few nights ago on MS-DOS 5.0. It was so much fun getting a color block to display on CGA.
Nevertheless, writing system code in assembly was probably going to cause a lot of insomnia and other side effects, especially when Microsoft was far from the domination force on IBM PC.
by markus_zhang - 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.by WalterBright
- Traditional reference how Microsoft was doubling down on UNIX with Xenix, before having a change of heart.
The Future of Xenix, Bill Gates Interview on Unix World, back in 1985
by pjmlp - 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.by walrus01
- decades later there are fuzix and elks running on 8085 or 8086 respectively:by fsiefken
- Unexpectedly, MS-DOS 2.0 included a /dev directory.
https://github.com/microsoft/MS-DOS/blob/main/v2.0/source/CO...
by add2 - A lot of early dos development was trying to see how many unix concepts they could fit, directories, pipes, environment, devices.by somat
- 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.by autoexec
- 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.
by mesrik