HP 9000/840

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Actually this is "only" a UNIX server, but nonetheless it has been put into the museum collection. This is the very first PA-RISC machine built by HP, which is built completely from TTL parts on several big PCBs. PA-RISC ist the name of the RISC architecture developped by HP that is still used in newer releases in today's HP servers. The operating system is HP-UX (in this case version 9.0 from 1992).

The interesting part of the entire system is not only the CPU itself but also the peripherals. There are several HP 7935 removable disk drives that can be attributed with "washing machines" due to their physical shape and size. Additionally there are a HP 7978 magnetic tape drive (right to the CPU) and several HP 9144 cartridge tape drives. The peripheral bus used to connect all the devices is the HP-IB. HP-IB stands for HP interface bus which started as a bus for measurement devices (like digital voltmeters) around the mid seventies.

This computer had been donated by HP to the "Institut für Informatik" (Institute for Computer Science) at that time. Amongst other tasks it was used to teach programming in RISC assembly. After the machine started losing its importance over the time, it simply stood there and ran idle until being declared as a museum piece.

The machine still runs today since the HP 7978 magnetic tape drive only works with this machine. So this computer is used whenever there is a need to read or write 9 track tapes or other HP-IB attached media, but it is also used e.g. to output curves and graphs with "gnuplot" to the graphics terminals available at the museum.

The PA-RISC CPU is as mentioned above built TTL technology and consists of the following five boards:

CPU-Board: Execution Unit

CPU-Board: Register File

CPU-Board: Floating Point

CPU-Board: Memory Controller

CPU-Board: Table Look-aside Buffer