20 Oct
2023
20 Oct
'23
6:05 p.m.
On Fri, Oct 20, 2023 at 1:46 PM Henry Bent <henry.r.bent(a)gmail.com> wrote:
I have a SIMH installation of Ultrix-11 3.1 on RL02
drives. Two RL02s is enough for a base system and four (which would be what the DQ614
provides, if it worked) would be more than enough for sources and work, etc.
Yes. 40MB should be plenty of room. 10MB was definitely not enough
for 2.9BSD, but at the time, I only had one RL02 drive.
The Ultrix-11 RL driver does fancy things with
overlapped seeks that I'm sure works on real hardware but on the DQ614, not so much.
Ah... I can see that. It wouldn't surprise me if the DQ614 got most
of its development and testing with RT-11 in mind, and possibly some
RSX-11.
I remember that the DEC RL controller (at least for PDP-11, not as
sure about the RL8A) did support some pretty handy things for a
multi-user OS, like overlapping seek, but I think in all the years I
worked with DEC gear, only a few machines had multiple RL drives.
Mostly I saw them as data transfer devices or for primary storage on
small (single-user) systems.
We did have one larger system, an 11/24 with four RL02, running RSTS/E
and whatever we were using for accounting software. I didn't work on
the machine myself except to physically disconnect and pack and move
it from one site to another when we consolidated our operations back
into one building.
-ethan