MS-DOS has been Open-Sourced!

His voice isn't much different!

I watch his videos because it's nice to have an insider view of what was the formative years of Microsoft's assimilation creation of a common office workspace. The anecdotes are deliciously 90's, the openness is refreshing, and the implementation detail is quite interesting.

My other half likes the videos because he has that quite monotone voice, with quite an even canter and the odd lingering pause that can send her to sleep.

Win win.

Seems right on brand for him. He wrote a book about his life and struggles being on the spectrum. I wouldn't be surprised if it's not intentional at all.

Amazon Link to book

Dollar-store Arnold says eat more cigars.

DOS wasn't a very complex OS and has already been reverse engineered more or less completely. Apps like DosBox already exist. It might cause a couple of minor revelations if/when the source is finally opened but I doubt it will have a big impact.

Very little. Older versions had already been open-sourced previously. This is specifically version 4.0, and the last version released was 8.0.

No, still the same.

4.0.x wasn't great but it was used pretty heavily.

It'll be slightly interesting to see it, and I'm not sure a more "popular" version like 5.0 would be much more interesting.

I'm curious about releasing 6.0 or 6.2, which MS was forced to recall because they "stole" some technology and put it in DOS. Although part thatd be interesting would be any damning code comments.

C compilers (at least on personal computers) weren't great at optimization back then and every kilobyte mattered - the user only got 640 of them, going beyond that required jumping through hoops.
Similar for MHz, hand optimization was important for performance since there was so little CPU time to go around.

Compilers were much less complex back then and didn't do a great deal of optimisation. Also hardware was slow, so your compiled code, which wasn't necessarily optimal either before or after the compilation phase, was at least half as fast as you wanted it to be.

If you wanted speed, you hand-rolled assembly.

Not everyone knew C.

Lack of trust: what was it doing behind the scenes? What's if it just went and ..... allocated memory all by itself!!

Optimization wasn't so good back then. People believed that they could write better assembly. For speed and size.

Memory was tight. C would include big libraries even if only one function was needed. If "hello world" was several k in size, that added to the suspicion (even though that was a fixed overhead in practice).

Because Ryan wrote it like this 10 years ago and nobody bothered to rewrite it in C.

Back then, I'd guess most developers were relatively fluent in assembly, so if there's only a small change to make, they'd just change the assembly and move on.