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The period 1986 - 1990:
The Control Data CYBER 840A

Installation and acceptance

CYBER 840A installation
A small change in the computer room

Spring 1986 was used by the Laboratory to negotiate about the replacement of the CDC CYBER 170-835 by a CDC CYBER 840A. The installation of the CYBER 840A took place in the early days of October 1986. The dismantling of the CYBER 170-835 started on Friday October 3, at 08.00 hour sharp. Before the power down, an additional full backup dump (DUMPF) of all files of the system was made. At 14.00 hours, the installation of the new CYBER 840A started. The weekend was used to power up the system and to execute the Customer Engineer's hardware tests. On Tuesday October 7, the formal function tests were executed. As these tests went well and much faster than expected, user jobs entered the system before the official formal function-test acceptance report was completed and signed. A month later, the system was formally accepted after showing no problems with downtimesand its true mean time between failure (MTBF).


input/output unit (IOU) CYBER 840 CPU

A couple of days of installation, the Laboratory received some technicians of the Royal Netherlands Navy. They always specified in their reports, signal cables had to be strapped at every 15 cm (6 inches). They were highly surprised to see a CPU with a ten cm thick package of signal and power coax cables hanging free in the CPU bay and connecting the various parts of the CPU. That the system was transported in that way by plane from Minneapolis, Minnesota and further on by trucks, was uncomprehendable for them!
The average CPU utilisation of the CYBER 840A was over 55% in the years 1988 and 1989.

The total CYBER 840A-system configuration consisted of: CYBER 840A CPU chips mounted on small cooling pipes

The configuration graph of April 1988 depicts this graphically.

Under NOS/VE a number of job classes were defined, each having their own "service"-definition: The number of simultaneous jobs in execution, priorities, maximum CPU-time, maximum time-slice, and so on.

CYBER 840 secundary cooling circuit
CYBER 840A cooling of the primary circuit by the secundary cooling circuit

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