Computer history: The end of the PDP era at Waalsdorp (1989)
Phasing out the PDP systems at Waalsdorp
At the end of 1986, a working group drew up a report on the replacement of the VAX 11/750s with a VAX 8300 (double CPU system) or a VAX 8500 (single CPU) system. Two utmost technical alternatives were indicated: replacement of the three existing VAX 11/750s with one VAX 8500 or the addition of a VAX 8200 to the VAX 11/750-VAX cluster. The three VAX 11/750 were: the scientific cluster VAX (VC), the administrative VAX (VA), and the graphics applications VAX (VG). To be able to continue to use microPower/Pascal and the COMTAL, we were not able to get rid of all VAX 11/750s. MicroPower/Pascal was used, among other things, for writing programs for the PDP 11/23 in Huijbergen for the Universal Dynamo Meter Bench (UDB project). This was a dynamometer of the Dutch Army on which military vehicles were tested under varying conditions. The vehicles under test were robotically controlled by the PDP, where the vehicle on the dynamometer underwent loads and accelerations that simulated driving through rough terrain. That incidentally went wrong once as a feedback wire came loose and the vehicle shot from the dynamometer through the wall.
The management of the Laboratory took a stance that there had to be a strict separation of the VAXes between the lab administrative work and the scientific work. Given the costs, it was decided to first solve the bottlenecks in the administrative work. A VAX 8350 was purchased; the two-year-old VAX 11/750 was sold to colleagues at the Prins Maurits Laboratory TNO in Rijswijk (PML) to replace their PDP 11/45.
Phasing out the PDP 11/44
To reduce the costs of maintenance of the central systems, at the beginning of 1989, it was indicated to the users of the 6 to 7 years old PDP 11/44 that the system would be decommissioned as quickly as possible. Nevertheless, the transition to other systems took more than a year. After the construction and manufacturing division had transferred all its data files to other systems, the disks could be overwritten several times as required for handling classified media. While waiting for the PDP system to overwrite the last removable disk package for the third time, a colleague system manager came by to talk about cleaning the FELBIS database on the administrative VAX. “Then he would load the MILCA data (MILitary Components Administration) from the PDP 11/44 into FELBIS and could transfer the disks of the 11/44 …. “.
A very surprised face of colleagues, who were ready to disassemble the PDP 11/44 with screwdrivers to make room on the computer floor for new VAX systems, was the result. After wiping the disk according to NATO rules, almost completed with a couple of bytes to go, there was not a single usable bit left on the disk package, not even on the sides of the disk platters. In the end, the Milca data were found on a magnetic tape only after a long search (‘and rescue’) operation.
The idea behind MILCA was that all components in systems delivered to the Armed Forces, including the smallest bolts, were provided with a traceable part number and description. This would make it possible for a replacement part to be delivered by TNO using the unique traceable part number. Each component had to be certified by the manufacturer. That was not a feasible idea given the high costs and small series. Anecdotally, adjusting screwdrivers that were included in a spare-case box also received such a part number. Those screwdrivers were simply bought at a hardware store around the corner and were provided by TNO fitted with a copper bezel and some Teflon tape.
