Last weekend (8th and 9th September 2018) saw another trip to the National Museum of Computing at Bletchley Park by the Askaris team to continue the restoration of the Scrapbook machine.
For anyone not familiar with Askaris’ work at the National Museum of Computing at Bletchley (feel free to browse previous articles relating to Bletchley), Sean Allison (Askaris Technical Director) has been working with his brother Ray to restore a system which was last operational around 35 years ago. The system – Scrapbook – used a method of information distribution using documents and hypertext – several years prior to the World Wide Web by Tim Berners-Lee.
This weekend we were accompanied by another DEC expert Malcolm Gill, who previously worked on PDP and VAX systems for Systime and ICM. A good weekend was had by all and included in-depth discussions on the Systime parties that were held in the 1980s and the irony of how we had all managed to survive and still be here all these years later – but that’s another story…
This week saw two notable breakthroughs:
The PDP-11 Lives! (… although it still needs a good surgeon to get back on its feet…)
We have now managed to get the 11/70 CPU running an operating system. XXDP was a DEC operating system used specifically to perform low level diagnostics on hardware. We have two XXDP disks which run – an old version will boot directly and a new version which can only be booted using the old version. This is because the system still has an issue with memory management and cache memory.
The other disk that boots successfully is RSX. This will be used to perform system operations such as disk management and ultimately, we hope, the copy of the Scrapbook disks. There is still the potential for issues though with this system as the cache and memory management issues still exist, however it is obviously less critical to achieve a minimal system boot using this OS. The good news however is that the original Scrapbook OS is called IAS which is strongly linked to RSX.
The DEC RM03 lives! (And it is just as noisy as we remember)
We had a slight issue with the RM03 over the weekend where it came up with a fault light after a few hours reporting an issue with one of the power supply voltages. After some fault finding, it turns out the fault was caused by a faulty fault card (shown on the right)!!
We managed to prove all of the RM03 functionality using the XXDP diagnostics and were successful in formatting and writing to a 67Mb disk pack.
We managed to get the RM03 fully working on a truly vintage piece of equipment called a TB216 test box. The drive was instructed to perform random seeks which is a great exercise of the voice coil and head carriage assembly.
If you are really interested, a video of the drive performing random seeks for the first time in around 35 years can be seen below: