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

Installation and acceptance

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).

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:

• The L-shaped CYBER 840A with 32 Mbyte memory, of which 4 MB was reserved for NOS/BE and the other 28 MB for NOS/VE. The I4 input/output unit (IOU) comprised 20 PP’s, 24 fast I/O-channels and a digital clock. Additionally, the IOU contained a TPM - two port multiplexer - which connected via two RS-232 lines the console and - optionally - a dial-in modem for remote maintenance. The cooling system had a secundary water cooling circuit with a 24-tons water chiller; the primary circuit in the system bays was a Freon-based coopling system. The CPU-chips used the 10K CMOS-chip technology that was at the first time used in the earlier CYBER 205 system. The chips were pressed by clips against one of the small cooling pipes of the secundary water circuit.
• Four 885-1 disk units each with 1.2 Gbyte split over two disk spindles were controlled each by two of the three disk controllers using the dual-channel control option, The 'I/O load' was split over the controllers and channels as best as possible.
• One 844-41 replacable disk unit was used for system maintenance and test purposes only.
• A dual-channel 7165 disk controller with a 895-1 disk unit having 2.1 GByte split over four disk spindles. This unit was used by NOS/VE. The transfer rate was 24 Mbps (3 MB/s).
• A 585 band printer having a maximum print speed of 2000 lines per minute and a chaining paper "skip" speed of 2.5 m/s.
• Five CDCnet device interfaces:
• One mainframe device interface (MDI) for the interconnection of the CYBER with the Ethernet (FELLAN) and a Unit Record Interface (URI) for controlling the 585-printer; The CDCnet had its own user interface that had the same command structure as the NOS/VE commands. The interface was highly servicing oriented. Some commands: %do help, %create_connection service_name=VAX, %display_connections, %change_working_connection connection_name=&a, %display_terminal_attributes, %change_terminal_attributes;
• A network device interface (NDI) that was used as a gateway with an XNS-stack (end 1988, it was replaced by a full compliant OSI TP4-stack) and a TCP/IP-stack;
• two, later three, terminal device-interfaces (TDI's) with initially 56 asynchronous ports up to 38.4 kbps and four (synchronous) HASP-ports up to 50 kbps.
• NOS/BE environment.
• NOS/VE environment: C, Fortran, Pascal, CYBIL, Programming Environment (PE), Accounting Analysis System; FCON (VAX Fortran conversion program), IMSL, Sciconic/VM, Abaqus (finite elements), PC-Connect, RMF/X-Modem.

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