D-116, an obscure clone of an overlooked mini computer [video]

If the DG Nova, which is the overlooked mini in the title, is overlooked, it's only because the people doing the looking weren't around when they were popular. By the standards of the day Data General made a lot of them. See here for a few more tidbits: http://ed-thelen.org/comp-hist/dg-nova.html

Fun to see this! I was an operator in our high school computer lab, which had a Nova 2 with a similar boot process (except we had a 9-track tape drive and 10MB Winchester to load binaries from...that paper tape is brutal). I had it memorized and could just about do it at “8x speed”. :) We ran multiuser stand-alone BASIC with four ASR33s in a room that must have violated noise-safety standards.

This multistage process is still how pretty much everything boots, BTW, except you start with a ROM rather than a human flipping switches. Back in those days a boot ROM was an expensive option you could do without.

The DG Nova in its day was a workhorse mini-computer. I worked with Bob McClure (Unidot) and built an "optimizing" C compiler that had surprisingly good performance. We ended up re-organizing the code generated so we could take advantage of the short offset and indirect addressing of the machine without adding extra instructions. Likewise, we used an unusual approach to managing stack frame addressing which was well suited to the DG Nova addressing.

The DG Nova hadware was simple largely because it was built in TTL and the ALU was a 74181. In the mid-1960's the final project in the logic design course was to design a DG Nova machine using TTL.

It's an Entrex D116, which is a clone of a Data General Nova 1200[1] if you don't want to watch the video.

There's an archive with some pictures from an eBay listing here: https://entrex480.blogspot.com/2017/05/entrex-480.html?m=1

[1] https://en.m.wikipedia.org/wiki/Data_General_Nova

I worked many years ago for a company that sold typesetting systems using DG Novas and Eclipses (16 and 32-bit both). As I recall, the RDOS CLI and system call manual was a wire-bound paperback that would fit into a reasonably sized back pocket. The AOS/VS system call manual needed a fairly large three-ring binder, and the AOS/VS CLI and utility manual came as a small one.

DCC and DG clashed over the cloning of the DG machine. See https://en.wikipedia.org/wiki/Data_General_Corp._v._Digital_....