UNIVAC mainframe computer from the 60s
Thanks to an cologne upper school this device has survived the last 25
years. At the end of the 70s, challenging computer science could be taught
with this computer. The time before it was used in a cologne industrial
factory.
Since September 2005 it is located in our museum. A regional German television
program reported on the transport of the UNIVAC 9400 (and 9300) which was
accomplished with two lorries due to the heavy weight. UNISYS covered the
expenses. The limited number of 9400 arrangements were build in
Frankfurt-Rödelheim, so this computer has almost reached his place of
origin.
Today there are only a few old mainframe computers which are still operable. Due to the complexness reperations are very difficult and time-consuming.
For the chance of a successful reperation the utterly complete installation,
an operating system, test programs and all manuals (schematic diagrams, service
instructions, operating instructions) are neccessary. There should not be
too many errors at the same time, otherwise it will be an endless adventure.
We had luck in many respects. The UNIVAC 9400 which was left to us is
complete and very good documentated. Furthermore: Two pensioners who live
near to the museum and who know the computer very well. They make it
systematically work again with an huge amount of background knowledge and lot's of
still available special spare parts.
Presumably this UNIVAC 9400 will be the only one in europe (perhaps even
worldwide) which still works (if not, please notify!). It still has small
faults, but we are on the right track to success.
Due to lack of space we had to slim the system (redundant parts are banned to the archive), thereby it is now a bit smaller, but the important components are still in the museum.
In the first picture (at the top) you can see (from left to right)
- console
- processor
- 2 storage cabinets with each 128 kB capacity
- tape controller
- 2 tape drives
- disc controller
- 2 disc drives
- high speed printer
- punch card reader
There is another tape drive, three disc drives and other components in the archive.
The UNIVAC series 9000 was designed in the mid 60s. All computers are built with "monolith circuits". That are ICs from the DTL series that were mass-produces about 1966. DTL means Diode-Transistor Logic; the transistors were integrated with simple OR- and NOR-gates, whereas the intrinsic logic was realized beyond the ICs with simple diods. Thus all computers needed only four different IC types. Strictly speaking these are still computers from the second generation, the scale integration was really small. For example, all flip-flops had to be realized with the help of NOR-gates.
The UNIVAC 9200 was selled as a "powerful, card oriented electronical data processing installation"
with a memory capacity up to 16 kB. The shortly later offered successor UNIVAC 9300
(this device is stored in the archives) was already band and disc oriented with up to 32 kB
memory capacity.
After all 1969 the UNIVAC 9400 was selled as a "flexible band and disc orientated computer
system featuring multi programming, real-time capacity and versatile possibilities data
telecommunication". A picture on the left shows
an advertising brochure from 1969
which presents the UNIVAC 9400's features.
All computers from the series feature a magnetic wire memory. This memory, at that time a
revolutionary new development, should be very dependable.
Due to the consistency from the memory contents that weren't cleared like the contents from a
magnetic core memory when reading, the cyclic time was only 600 ns per 2 bytes. Regenerating the
memory contents wasn't neccessary.
However after a short period of time, frequent failures showed that he couldn't keep his
promise. Therefore the storage from our UNIVAC 9400 was changed over to one of INTEL's first
semiconductor memories. More than 1200 first generation ICs (made by INTEL) were neccessary to
realize the huge size of 256 kB. The magnetic wire memories would not be reparable any more.
The slow periphery (max. 85 kB/sec) like paper tape reader, punch card reader and
high-speed printer were connected with a multiplex channel. There were two selector channels for
periphery with fast data exchange (333 kB/sec) like tape drives and disc drives.
The UNIVAC 9400's software was offered with many routines and compilers, like e.g. assembler and the higher programming languages COBOL and FORTRAN. An additional "report generating program" made it possible to generate a "spreadsheet".
There was a basically difference between this computer and its successors: About 600 individual bit-states could be displayed with glow lamps. Every register can be seen and changed, the state of every single storage cell can be displayed and changed. This makes this computer to an ideal "teaching computer". The aim was to find failures occured by defect components in 1969. The maintenance staff could do this only with these "insights". This computer is really extremely maintenance-friendly.