Data General Nova

Led by founder and technical leader Edson deCastro in 1968, the first Nova was delivered in 1969. Mr. deCastro previously worked at DEC (Digital Equipment Corporation) as Product Manager for the PDP-8 series and left DEC, along with a few other DEC people, to form Data General

The big innovations of the Nova were not technical as much as packaging. It saved money and increased reliability by packaging as much as possible of the computer on a single huge 15 inch by 15 inch printed circuit board.

The standardized backplane and I/O signals that implemented a simple but effective I/O design made interfacing programmed I/O and Data Channel devices simple compared to other machines of the day. The backplane had wirewrap pins that could be used for non-standard connectors or other special purposes.

It was a 16-bit, four accumulator and each instruction was contained one word. The instruction format could be broadly categorized into one of three functions: 1) register-to-register manipulation, 2) memory reference, and 3) input/output.

The register-to-register manipulation was almost RISC-like in its bit efficiency; and an instruction that manipulated register data could also perform tests and even elect to discard the result.

The Nova's biggest competition was from the newly-born DEC PDP-11 computer series, and to a lesser extend the venerable DEC PDP-8 systems.

Some have said that the Nova was pretty crude compared to its competitors, but it was quite effective and very fast for its day, at least at this low-cost end of the market. In fact, the SuperNova computer's 300 nanosecond cycle time was the fastest minicomputer for over a decade following its introduction.

There are even 16-bit Novas and Eclipses running today (2003) in a variety of applications worldwide.

There is a diverse but ardent group of people worldwide who restore and preserve legacy 16-bit Data General systems, and a web search of Data General Nova, Eclipse, RDOS, or the various other DG-related keywords should yield good results. Bob Supnik's fantastic SimH project [1] (http://simh.trailing-edge.com) includes a basic Nova emulator in a user-modifiable package, and SimuLogic's web site [2] (http://www.NovasAreForever.com) attempts to archive everything that is DG plus provide free and commercial products.