This site is all about my hobby (recent one at that) restoring Data General Corporation (DGC) computer systems, it is primarily aimed at being a resource for anyone following a similar route or has an interest in trying to bring something old back to life!
Me
Mid 1984 school had finished and I was lucky enough to land a job the very next day. It was with a service company that specialised in peripheral maintenance and reconditioning; predominantly disks manufactured by Control Data Corporation (CDC) and Data General (DG). My first role here was more mechanical than electronic replacing bearings in drive spindles and then running checks to ensure they ran true and were in balance. I also worked on head actuators for the Data General Gemini (6067) 10+10Mb disk drives and the Phoenix (6045) 5+5Mb. The problem these drives had was that the coating on the actuator base (on which the carriage bearings ran back and forth carrying the heads) wore off after a period of time and became pitted causing the heads to run untrue and at worst crash. We devised a method of refurbishing these units by machining off the forged rails in a jig, drilling out the base and tapping new mounting points. Then we would fit new stainless steel rails to the base, replace the bearings in the carriage, reassemble and test. We refurbished 100’s of these for Data General worldwide. If you have a Phoenix or Gemini drive with silver actuator rails I probably have had my hands on it at some point!
From bits of drives to whole drives. My next role was in drive repair which involved the refurbishment, test and alignment primarily on CDC 9762 80Mb, 9766 300Mb and 9775 600 Mb drives (big beasts for CRAY). These use the familiar multi-platter packs you often see in large mainframe computer rooms of old. The 300Mb had 10 platters and the 600Gb 20 platters – that was a big heavy pack! By now I have completed my micro-electronics courses and moved on to analogue electronics.
Whilst continuing my further education I started to work on the PCB’s from the CDC disk drives, repairing them to component level. This also involved redesigning board sections (with pin compatible miniature PCB’s) to overcome supply constraints for some common failing components that were no longer available (op-amps as i recall).
We also started to offer repair and refurbishment services for tape transports. A high volume of Cipher F880/F890 (Pertec Interface) 1/2″ 9 track tape transports (flat) as well as a the Data General (upright) vacuum drives were repaired.
It was around this time we started repairing peripherals and PCB’s for GE Calma (a CAD system house that used DG CPU’s (N3/S140) and chassis along with OEM controllers, disks and tape) to repair and refurbish their peripherals. GE Calma gave us an Eclipse S140 (5 slot) , CTOS (as I recall – derivative of RDOS) tape as well as the 3rd party controllers that GE Calma used to build their systems.
My role then moved to component level repair of Spectra Logic controllers and other 15″ PCB’s that offered a SMD and Pertec interface on a single 15″ PCB in the DG chassis. This PCB (Spectra Logic) quickly became a firm favourite of mine; it used AMD 2901 bit-slice CPU’s and had quite a bit on code on board (for the time) which emulated DG disks. I estimate that I repaired close to 300 of these controllers during my time with that company as well as Nova 3 CPU, Nova 4 and Eclipse S140 CPU’s (the latter two again AMD 2901 based) and DG Memory PCB’s (even some logic on the old core memory’s).
Using the Eclipse S140 daily as my test bed I grew to love it’s small 5 slot chassis. Not quite as ‘flashy’ as the Nova 3 but I liked its small size and that I could run it with just the CPU and Spectra Logic controller booting from a Cipher F880. I also used the Nova 3 to test sample refurbished actuators for DG. In spare time I also built and played played with an RDOS system on the Nova 3 along with some higher level languages such as Business Basic.
There was something quite magical (to me anyway) seeing these peripherals moving/working away in front of my eyes and the PCBs working away through my logic analyser. It was real rather than simulated with an disk or tape exerciser, you could actually visualise the data being read from the head(s) passed down the cabling, through the controller and into RAM and executed. It was reminiscing about this visualisation that made me want to obtain and restore (to operation) a DG system – and here I am starting this new hobby with a MV/9800 one of the last 15″x 15″ chassis designs – the last of the 32bit Eclipse’s.
Once I left my first company I entered into the world of Field Engineering, still working on some Data General systems (Nova’s, Small MV’s and AViiON’s) but my focus moved to Texas Instruments DS990 mini systems running DNOS and DX10 and later the TI S1500 Explorer which ran UNIX on a 68000 and finally SUN Sparc systems and large arrays running SOLARIS.
Finally for my third and current job I shifted to the other side of the fence and I now manage IT and have others service it 🙂
Preservation
If you are considering scrapping or sending anything Data General related for disposal to a salvage or recycling plant please consider sending it for preservation instead. You can contact me here if you have any Data General System, Peripherals, Displays, Documents, Manuals, Cables, Terminals, Parts, Spares, Floppy’s or Tapes you wish to dispose of.
I am based in Oxfordshire, UK.