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Here’s a complete printset of the Venus Ibox, from 1984. It includes Ibox block diagrams, module and MCA block diagrams, and schematics for the MCAs and modules.

I’d bet my bottom dollar that there were ECOs after this version. But this hardware ran VAX/VMS and oodles of software.

Most of the page tops are faded. 75% of it is due to fading in the originals, and 25% is due to less-than-meticulous copying by FedEx.

Venus Ibox 1984-08-18


In a comment on my Thoughts on DEC post, Tom Miller offered a rat’s ass if I scanned in my VAX 8600 (Venus) Ibox microcode listing.

Well, here’s Venus Ibox microcode v3.73, generated on 7-May-1984. Tom, you owe me one rat’s patootie.

This ran on Venus through the end of 1984. I had transferred to Alan Kotok‘s Simplified Architecture for Fast Execution (SAFE) project, where I was looking into VAX-11 emulation. Large VAX Engineering’s senior management called an “all hands on deck” emergency, and everyone needed do whatever they could to help Venus ship on time.  So, I informally returned to work on Venus and ran one of the lab debug shifts. It was equally exhilarating and stressful… An, “I wouldn’t trade those memories for anything in the world,” and, “I hope I never go through something like that again,” experience.

This version ran VMS and oodles of VAX programs.  I don’t know if there was a later version; if so, I never heard about it.

BTW, here’s a nice paper about why DEC went down the tubes.


I’m off this week, and while loafing around the house I took an hour or so to search the web about Digital Equipment Corporation (DEC), a former employer. That was a mistake, because it got me thinking about my past. This was fun for a while, and then it got sobering.

I worked for DEC from February 1978 until August 1996. During the glory years (before 1986) it was an adventure. We were on a world-changing mission. The code I wrote would live on and the work I did was so cool. Working for DEC was like working for Microsoft in the ’90s or ’00s, except that nobody hated your company. It was like working for Google except that nobody thought you were evil. It was like working for Amazon but pretty much everyone loved working there and it seemed like the world rooted for you to succeed. Most of all, everything we did clicked. There were some bad decisions, but the company always recovered and went on to greater glory.

I wrote CPU microcode for the VAX-11/750 and VAX 8600, worked on some cancelled projects that nobody will ever know about (ECL microprocessors, large ECL mainframes, a new RISC architecture), and my last project was working on Windows NT at DECwest.  In its day the VAX 8600 micropipeline was the coolest thing since sliced bread. How many people today know or care about it? Zip.

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