UNIVAC II
The UNIVAC II was an improvement to the UNIVAC I that UNIVAC first delivered in 1958. The improvements included core memory of 2,000 to 10,000 words, UNISERVO II tape drives which could use either the old UNIVAC I metal tapes or the new PET tapes, and some of the circuits were transistorized (although it was still a vacuum tube computer). It was fully compatible with existing UNIVAC I programs for both code and data.
Circuit elements of entire system
Above figures are approximate and do not include input-output devices.
Programming and numerical system
Decimal point occurs at the right of the sign digit.
Arithmetic unit
Addition, subtraction, and multiplication times given below include reading and executing the instruction. The time includes formation of the result in the accumulator. All instructions, however are performed at minimum latency rates.
Magnetic core
All users utilize a 2,000 word 24,000 digit, magnetic core storage unit. Each of the planes is divided into two sections of 50 by 40 cores, making 2,000 cores in each section. Each section contains one core - for one binary position (bit) - of every one of the 2,000 words. The same relative binary position of the other half-word is held in a core in the same physical location in the other section of the plane. Thus each plane contains two binary positions in each of 2,000 words; the first and 43rd, for example, or the 9th and 52nd. Physically the memory is a rectangular prism 7.25×10×12.75 inches (18.4×25.4×32.4 cm).
UNIVAC 418
The UNIVAC 418 was a transistorized, 18-bit word core memory machine made by Sperry Univac. The name came from its 4-microsecond memory cycle time and 18-bit word. The assembly language for this class of computers was TRIM III and ART418.
Over the three different models, more than 392 systems were manufactured. It evolved from the Control Unit Tester (CUT), a device used in the factory to test peripherals for larger systems.
Architecture
The instruction word had three formats:
Numbers were represented in ones' complement, single and double precision. The TRIM assembly source code used octal numbers as opposed to more common hexadecimal because the 18-bit words are evenly divisible by 3, but not by 4.
The machine had the following addressable registers:
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