A second generation calculator: The BULL GAMMA 10
BULL Gamma 10 electronic data processing system
In 1963 BULL (General Electric) presented the BULL GAMMA 10 (G10)
which was intended for commercial purpose and puchcard
computing. It was the direct successor of the Tabulating Machine.
Compared to the really big mainframes, the G10 was intended to
be set up in a 20 square meter room, without air conditioning.
The maximum power input was 2.5 kW.
The standard equipment contains a CPU with panel, a punchcard reader/puncher unit and a barrel printer. The RAM consists of a 1kb core memory which could be extended up to 4kb capacity. There are 59 different opcodes to program the CPU.
The cycle time from the core memory is 7 micro seconds. The calculator is capable of reading and punching 300 cards per minute. Five punchcards per second, that is an amazing speed – therefore the punching unit is generously built. The printer can only print up to 300 lines per minute. Compared to our Univac 9400 this is quite slow – the Univac 9400 is capable of printing more than 1000 lines per minute.
Gamma 10 uncovered
The chassis is metallic bright and glossy. It is clearly arranged
and therefore the machine is quite easy to maintain.
By now the whole mechanics are working again, which is the core part of the computer. After adjusting the temperature of the heated core memory and replacing some broken transistors, the program for duplication punch cards runs again, as well as some mathematical programs.
The control panel could be used for monitoring running
programs, as well as for early "test driven development"
The picture shows details of the programmer's part of the control panel. These buttons and switches are intended for debugging a program step-by-step and for reading out the contents of registers, the ALU and RAM, and, finally, for assembling and executing new computer instructions.
All output is driven by lime-green "DM 160" miniature tubes.
This is a picture of a typical GAMMA 10 board. On the mainboard,
all conductor paths are aligned horizontally while on the small
plug-in boards (flip-flops, amplifiers, etc.) they are mostly
vertically oriented. Almost all transistors are made of germanium.
The slow non-time-critical logic (like card controlling) is performed by 573 relays. Building up such an amount of wear parts is quiete brave.
Summing up, there were about 570 boards like this one in the GAMMA 10 (without counting the printer interface). The GAMMA 10 was sold as a quite cheap electronic data processing system. We have gotten an original list of prices for this device from 1968/69, when this model was already out-of-date and hence very cheap:
CPU with 4kB core memory: 267.000,- DM (about 133.000,- Euro or Dollar)
Printer: 105.000,- DM (about 50.000,- Euro, Dollar)
While our GAMMA 10 is in a very good shape, we cannot use the
printer any more, since all electronics are missing.
But we were very lucky: We got a printer from the "Federation des Equipes Bull" from France which is a perfect match for our Gamma 10. Although some parts like the outer enclosing are missing we can use parts from another printer that is beyond repair to restore this printer to working condition. Nevertheless this will be a lot of work.
Printer waiting for its restoration