UNIVAC 1100/2200 series

The UNIVAC 1100/2200 series is a series of compatible 36-bit computer systems, beginning with the UNIVAC 1107 in 1962, initially made by Sperry Rand. The series continues to be supported today by Unisys Corporation as the ClearPath Dorado Series. The solid-state 1107 model number was in the same sequence as the earlier vacuum-tube computers, but the early computers were not compatible with the solid-state successors. Fixed-point, either integer or fraction Whole word – 36-bit (ones' complement) Half word – two 18-bit fields per word (unsigned or ones' complement) Third word – three 12-bit fields per word (ones' complement) Quarter word – four 9-bit fields per word (unsigned) Sixth word – six 6-bit fields per word (unsigned) Floating point Single precision – 36 bits: sign bit, 8-bit characteristic, 27-bit mantissa Double precision – 72 bits: sign bit, 11-bit characteristic, 60-bit mantissa Alphanumeric FIELDATA – UNIVAC 6-bit code variant (no lower case characters) six characters in each 36-bit word. (FIELDATA was originally a seven-bit code of which only 64 code positions (occupying six bits) were formally defined.) ASCII – 9 bits per character (right-most eight used for an ASCII character) four characters in each 36-bit word Instructions are 36 bits long with the following fields: f (6 bits) - function designator (opcode), j (4 bits) - partial word designator, J-register designator, or minor function designator, a (4 bits) - register (A, X, or R) designator or I/O designator, x (4 bits) - index register (X) designator, h (1 bit ) - index register increment designator, i (1 bit) - indirect address designator, u (16 bits) - address or operand designator. The 128 registers of the high-speed "general register stack" ("integrated circuit registers" on the UNIVAC 1108 and UNIVAC 1106 models), map to the current data space in main storage starting at memory address zero. These registers include both user and executive copies of the A, X, R, and J registers and many special function executive registers.