First VAX-11/730 VMS Boot! (was: Re: VAX-11/730 %BOOT-F-Unexpected Machine Check)

tony duell ard at
Fri Jun 12 15:44:44 CDT 2015

> Using a version 58 console tape image provided to me by one list member, and massaged into a usable state 
> by another list member, I just booted OpenVMS 7.3 off the R80 drive on my VAX-11/730 for the first time since 
> buying the machine. Woohoo!

Well done. The 11/730 is, to me, an interesting machine and one of only 2 VAX families that I would want to
run (the otber being the 11/780 -- if I had space for it). To build a complete VAX on 3 hex cards using 
standard ICs is a good hack.

There is one bit of design craziness in the 11/730 IMHO. The CPU control store is dynamic RAM. With the
result that the CPU has to wait for the control store to be refreshed every so often. Why they didn't use
SRAM is something of a mystery....


> Eventually, I'd like to run an older version of VMS than 7.3 on it. Preferably, something contemporary to when 
> the 11/730 was still sold, or at least from before any sane 730 users upgraded to newer and faster VAXen. Of 
> course, that assumes I can procure suitable installation media, or usable images with which to create it.

I think my 11/730 was running VMS 4.7 when it was shut down. 

A long-term project for me is to get my 11/730 running again. It was decommisioned and dismantled, and I 
have never got round to putting it all back together.

The CPU box looks fine. It contains the 3 CPU cards, the RB730 disk controller (no FP730 though), 4
megs of RAM (2 DEC cards, 2 NatSemi ones), a TSU05 tape controller and a DMF32 serial/parallel
card. All the ribbon cables have been removed, but I think I have them. Re-cabling that tray under
the CPU is going to be 'fun'

The R80 is in bits. The HDA is intact, locked, and the spindle pulley is taped down so it should be
OK. I have the chassis metalwork (in need of minor repairs) with the power harnesses and switch/lamp
panel fitted. Also the PSU, spindle motor assembly and the 4 PCBs (R/W, microprocessor, personality, servo)
So far I have not unearthed the box of screws and internal ribbon cables or the drive belt. But those can
probably be obtained (the belt might be a problem....)

I have the half-rack to hold it, along with the slides -- somewhere. What to put in the top bay? Originally
it was the TS05, which I do have. I am wondering how useful that is, and perhaps a Unibus expansion box
would be more useful. But anyway...

I've read all the applicable manuals on bitsavers. Did DEC ever publish the 11/730 microcode source? That 
would be interesting. Ditto the source for the 8085 firmware. And the R80 firmware. Was there ever a
technical manual for the R80 (I have the service manual and printset, I am thinking of a theory-of-operation
manual coverting the servo, etc)

As I said, a long-term project.


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