The UNIVAC Solid State was a magnetic drum-based solid-state computer announced by Sperry Rand in December 1958 as a response to the IBM 650.
It was one of the first[1][2] [citation needed] computers offered for sale to be (nearly) entirely solid-state, using 700 transistors, and 3000 magnetic amplifiers (FERRACTOR) for primary logic, and 20 vacuum tubes largely for power control.
The SS II series included two enhancements – the addition of 1,280 words of core memory and support for magnetic tape drives.
There was no operating system as we have come to know them in recent years; every program was completely self-contained, including the boot loader that initiated execution.
[3] The UNIVAC Solid State was a two-address, bi-quinary coded decimal computer using signed 10-digit words.
For efficiency, programmers had to take into account drum latency, the time required for a specific data item, once written, to rotate to where it could be read.
The decision to use magnetic amplifiers was made because the point-contact germanium transistors then available had highly variable characteristics and were not sufficiently reliable.
The magnetic amplifiers required clock pulses of heavy current that could not be produced by the transistors of the day.
The powerful high-voltage signal was stepped down to a 36-volt, high-current clock by oil-filled transformers that were distributed about the machine.
The clock tube was enclosed in a shielding box that constrained both radio emissions and viewing by eyes of other than Univac's field engineers.
Since many gears, electrical contact cams were affixed to the main shaft with taper pins, the P 67 with its severe stopping dog clutch would cause timing loss more frequently than the P 147.
Most emergency maintenance time was spent replacing worn and damaged taper pins and retiming the machine.