[TUHS] Re: DG UNIX History

[Stuff Received <stuff@riddermarkfarm.ca>]

On 2022-11-14 17:31, Clem Cole wrote:
> On Mon, Nov 14, 2022 at 5:12 PM Paul Ruizendaal <pnr@planet.nl> wrote:
>
>     Following on from the exchange on TUHS about DG-UX, it would seem
>     to me that the (Unix) unified cache was invented at least three
>     times for Unix:
>
> Not to quibble too much, but s/cache/memory/  I think is a fairer way 
> of saying that.
>
>     - John Reiser at AT&T
>     - At Sun
>     - At DG
>
> - At CMU (Mach)
>
> The interesting thing again, is that while they while all of these 
> implementations seem to have been technologically 'better' - only Mach 
> lived on from the original developers.  And in the case of Mach, by 
> the time it was mainstream (macOS) the original implementation had 
> been replaced a few times - so while the concepts are there, I don't 
> think much of the Original CMU code is left in XNU/Darwin [or for that 
> matter in the OSF flavors -- Tru64 rewrote it but it died and the 
> OSF/RI kernel never went anywhere either].

The CMU copyrights are still there 
(https://github.com/apple-opensource/xnu/tree/master/osfmk/mach). 
Perhaps someone far more knowledgeable than me could spelunk.

>
> As I said, the lesson to TUHS -- as much as I'm a techie and I am 
> interested in the 'proper' way of doing things ... "good enough" is 
> often what rules.

Indeed.

>
> It's too bad none of the good memory implementations made it into 
> >>systems<< that lasted.
>
> Clem
> ᐧ