Making an RT-11 TU58 Image

Ethan Dicks ethan.dicks at
Sun Dec 7 13:58:01 CST 2008

On Mon, Dec 8, 2008 at 8:22 AM, Dave McGuire <mcguire at> wrote:
> On Dec 4, 2008, at 4:26 PM, Curt @ Atari Museum wrote:
>> I've got a large box of TU-58's with boot up and diags for a Vax 11/750,
>> any out there want to make archives of them or has that already been done?
>  Please don't let them go to far away.  I just got an 11/750 (thanks Pat!),
> and while I have a set of tapes, I've not yet gone through them to see
> what's there.

I'm also interested in any tape images for the 11/750.  I haven't
fired mine up in years, but more discussion on the list about them
will certainly motivate me to do so.  I often muse about what to do
about disk, though.  The last time I powered an 11/750 up, it had an
SI9900 w/two SMD disks, and a UDA50 w/RA81.  I kinda don't mind the
800-1000W of the CPU, but three 14" disks get expensive to keep
turning (as I've posted before - nearly a gig of storage on this
machine *20 years ago* - all bought new in the early-to-mid 1980s for
around $50,000)

>  I did just get the correct tubing to fix the gooey TU58 roller though, and
> have performed a "smoke test" on the machine, so I hope to be able to fire
> it up "for real" soon.


>  Ahh, the 11/750.  Such personality in that machine!  And great memories for
> me, from when I was a sysadmin on one of those and a pair of MicroVAX-3600s
> (all running VMS) years ago.  I am so very happy to have this machine here.

Agreed.  My first experiences with VMS and UNIX was on my 11/750 in
1984. I was quite happy to be able to save it when the company closed
ten years later.  In our heyday, we had dozens of users on this box,
and it was quite responsive as long as we didn't have too many people
sitting around idle in MASS-11 and VMS MAIL (those were our highest
memory-using apps - more than about 20 users in them, idle or not, and
we started paging and swapping).  After the company went through a
couple of rounds of downsizing, there would be frequent times that
there were only 3 active users on the machine - it was downright peppy
then.  Even into the mid-1990s, it was a nice single-user machine.
The only other machine we had that could touch it was a MicroVAX-II,
but that was less fun as a software development platform because
despite a CPU that was easily 50% faster, and 12.5% more memory, the
disk performance difference between  Qbus MFM disk (RD53/RQDX3) and
MASSBUS disk really came out during compiles.

At some point I'm going to have to finish my plans to mount a 5.25"
disk of some type (ESDI, SMD, SDI...) inside a 11/750 for a
single-cabinet system.  At its maximum extent, ours spanned 5 cabinets
full-time (CPU, TU80+BA11, SI9900+SMD disk+BA11, TU78, 80-port patch
rack), and occasionally reached out to an RA81 on our 8200 via the
B-port (so we could back the drive up and move massive amounts of
files quickly)  Nice, but more space than I have at home (and I
couldn't recreate the original configuration now since the TU78 was
not rescued with the CPU, way back when).

Dave, if you have any 11/750 questions, I'll do my best to help.
Since it was my introduction to the VAX, I've always had a place in my
heart for them and I love to see them still kicking.


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