[TUHS] DG UNIX History
Clem Cole
clemc at ccc.com
Sun Nov 13 05:36:05 AEST 2022
To be honest, I've forgotten many (most) of the details. But that sounds
about right. As I remember it, it was like SunOS. The key point was that
the kernel only had one view of the memory system period, no FS
buffer cache etc...which was a departure from many of the traditional UNIX
implementations. IIRC they did not support BSD's mmap -- but check the
SVR3 docs to be sure -- they had the SVR3 user interfaces but none of the
BSD ones. They did support the System V shared memory, however. I do seem
to remember there was something funny in the driver interfaces, it was just
like UNIX only different, and that causes some heartache - but it was
fairly straightforward to move a DMA driver like getting a VME Xylogics
tape controller to work, but it took a little tweaking. I've forgotten
exactly why that was -- it's been a long time ago.
Clem
ᐧ
On Sat, Nov 12, 2022 at 1:36 PM Larry McVoy <lm at mcvoy.com> wrote:
> On Sat, Nov 12, 2022 at 01:04:30PM -0500, Clem Cole wrote:
> > On Sat, Nov 12, 2022 at 11:52 AM <arnold at skeeve.com> wrote:
> > > DG-UX was a pretty generic SVR3
> > >
> > User space was generic. But the SVR3/88K kernel was a heavy rewrite.
> > LCC did a lot of work with DG adding stuff too it -- it was very well
> done
> > by the DG team in NC. The memory and FS was well integrated.
>
> So read()/write()/mmap() all shared the same cache like SunOS? In SunOS
> the
> only things not in the page cache were directories and inodes. All data
> pages had one, and only one, place to be (ZFS broke this in Solaris,
> which has always blown my mind).
> --
> ---
> Larry McVoy Retired to fishing
> http://www.mcvoy.com/lm/boat
>
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