Thanks, Tim. Burroughs made a lot of fixed head disks at the time. I
can't identify the model, but the IA2 (see page 7-4 of the B6700
Hardware Handbook, on bitsavers) seems like a possibility. It has 7552
sectors per surface vs 8000, but Burroughs sectors were longer than DEC
sectors (180 x 8b = 1440b vs 32 x 36b = 1152b), so perhaps DEC format
had more sectors per track.
While the 18b- and 36b-groups used the same disk buyout, they went to
different vendors for drums. The Type 24 and RM09 came from Vermont
Research; the RM10B from Bryant.
/Bob
On 2/27/2016 12:00 PM, [email protected] wrote:
Message: 3
Date: Sat, 27 Feb 2016 09:31:59 -0500
From: Timothe Litt<[email protected]>
To:[email protected]
Subject: Re: [Simh] RB09 == RD10
Message-ID:<[email protected]>
Content-Type: text/plain; charset="utf-8"
On 27-Feb-16 08:23, Bob Supnik wrote:
>Max Burnet gave me a pointer from some old price lists, showing that
>the RD10 had very similar specs to the RB09. The RC10 manual confirms
>it - same BCD addressing of tracks and sectors, same number of tracks,
>same sectors per track, same words per sector (32 x 36b for the RD10,
>64 x 18b for the RB09). So the "RD10s" on some PDP-9s in the services
>listing are actually RB09s, at least at the drive level.
>
>I still don't know what an RC09 is. Alternate name for an RB09?
>Half-sized variant? Another mystery is who made the actual drive
>mechanism. It precedes DEC's first internally designed fixed head
>disk, the RF09/RS09, by two years.
According to the option module list, the RC09 is a "Control for
Burroughs Disk" The design engineer was J. Milton.
That makes sense, as the RC10 was the PDP10 controller for disk and drums.
FWIW, Family members: the RD10 was made by Burroughs. The RM10B drum
was by Bryant. SW documentation was removed from the PDP-10 doc set in
the 80s, but as I wrote previously, I believe the tech manuals are on
the FS microfiche. The section with the red stripes on top.
The drums were notoriously unreliable. Especially the ones in the Mill,
though things improved when someone realized that they tended to crash
when semitrailers bumped into the loading dock above them....
_______________________________________________
Simh mailing list
[email protected]
http://mailman.trailing-edge.com/mailman/listinfo/simh
