Bendix G-15

The Bendix G-15 was a small (about the size of a refrigerator), slow (serial), vaccuum tube magnetic drum computer, mainly used in scientific and engineering applications.

The G-15 (along with the LGP-30, which Bendix had acquired from Royal-McBee) were eventually acquired by CDC.

Memory: Magnetic drum with:

• 20 tracks of 108 words each for main memory; one of these tracks is used as the I/O buffer.
• 4 tracks of 4 words each for high-speed memory.
• 3 tracks of 2 words and 1 track of 1 word for arithmetic.
• 1 track of 1 word for control.
• Timing tracks.

Word size:

• Single precision: 29 bits.
• Double precision: 58 bits.

An interpreter provided a complex virtual instruction set.

The console was an electric typewriter. Off-line storage was paper tape on spools in aluminum cartridges that slapped onto the front of the machine.

The University of Delaware's first computer (long before my time!) was a G-15. It was installed in 360 DuPont Hall. One of the EE students used it to do the word processing of his thesis or dissertation. The photo-electric paper tape reader and the machine were capable of reading much faster than the motors were able to move the tape, so he was able to read tapes much more quickly by manually pulling the tape through the reader, hand-over-hand, and letting it pile up in a trash can, later to be wound back onto the spool.

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