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.
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:
As I recall 8 inch class HDD (5, 10, 20MB?) were called Winchester in the pre-PC/XT era, named for the earlier IBM product, and then the terminology carried on into the microcomputer/desktop world when the 5.25" full height HDD was introduced for the XT.
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.
Unexpectedly, MS-DOS 2.0 included a /dev directory.
https://github.com/microsoft/MS-DOS/blob/main/v2.0/source/CO...
A lot of early dos development was trying to see how many unix concepts they could fit, directories, pipes, environment, devices.
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.
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...
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.
As I recall 8 inch class HDD (5, 10, 20MB?) were called Winchester in the pre-PC/XT era, named for the earlier IBM product, and then the terminology carried on into the microcomputer/desktop world when the 5.25" full height HDD was introduced for the XT.
My dad still called it "Winchester" well into the 80s. I remember when we got our first "Winchester", a 20MB hard drive.
>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
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.