15 Nov
2022
15 Nov
'22
2:21 a.m.
On 2022-11-14 17:31, Clem Cole wrote:
On Mon, Nov 14, 2022 at 5:12 PM Paul Ruizendaal
<pnr(a)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