The UNIVAC 1100/2200 series is a series of compatible 36-bit computer systems initially made by UNIVAC. The series continues to be supported today by Unisys Corporation as the ClearPath IX.
==Architecture==
===Data Formats===
*fixed-point arithmetic either integer or fraction (mathematics)
**Whole word - 36 bit (one's complement)
**Half word - two 18 bit fields per word (unsigned or one's complement)
**Third word - three 12 bit fields per word (unsigned)
**Quarter word - four 9 bit fields per word (unsigned)
**Sixth word - six 6 bit fields per word (unsigned)
*Floating point
**Single precision - 36 bits: 1 sign bit, 8 bit characteristic, 27 bit mantisa
**Double precision - 72 bits: 1 sign bit, 11 bit characteristic, 60 bit mantisa
*Alphanumeric
**Fieldata - 6 bits
**ASCII - 9 bits
===instruction set===
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.
Address
Register
Contents
000
Unused
Unused
001
X1
Increment
Modifier
...
...
Increment
Modifier
013
X11
Increment
Modifier
014
X12/A0
Overlap (X or A)
...
...
Overlap (X or A)
017
X15/A3
Overlap (X or A)
020
A4
Accumulator
...
...
Accumulator
033
A15
Accumulator
034
A15+1
Unassigned (A)
...
...
Unassigned (A)
037
A15+4
Unassigned (A)
...
Executive
Protected Executive
101
R1
Special (R)
...
...
Special (R)
117
R15
Special (R)
...
Executive
Protected Executive
177
Executive
Protected Executive
===Processor register===
The 128 registers of the high speed "general register stack", 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.
The table on the right shows the addresses (in octal) of the user registers.
There are 15 index registers (X1 ... X15), 16 accumulators (A0 ... A15), and 15 special function user registers (R1 .. R15). The 4 J registers and 3 "staging registers" are uses of some of the special function R registers.
One interesting feature is that the last 4 index registers (X12 ... X15) and the first 4 accumulators (A0 ... A3) overlap, allowing data to be interpreted either way in these registers. This also results in 4 ''unassigned'' accumulators (A15+1 ... A15+4) that can only be accessed by their memory address (double word instructions on A15 do operate on A15+1).
==UNIVAC 1100 series==
#UNIVAC 1107 introduced in 1962
#UNIVAC 1108 introduced in 1964
#UNIVAC 1106 introduced in 1969
#UNIVAC 1110 introduced in 1972
#UNIVAC 1100/10 redesignation of UNIVAC 1106 in 1975
#UNIVAC 1100/20 redesignation of UNIVAC 1108 in 1975
#UNIVAC 1100/40 redesignation of UNIVAC 1110 in 1975
#UNIVAC 1100/181 introduced in 1975
#UNIVAC 1100/80 introduced in 1977
#UNIVAC 1100/60 introduced in 1979
#UNIVAC 1100/70 introduced in 1981
#UNIVAC 1100/90 introduced in 1982
==SPERRY 2200 series==
In 1983Sperry Corporation discontinued usage of the name ''UNIVAC'' for their products.
#SPERRY 2200/100 introduced in 1985
#SPERRY Integrated Scientific Processor introduced in 1985
==UNISYS 2200 series==
In 1986Sperry Corporation merges with Burroughs Corporation to become Unisys Corporation.
#UNISYS 2200/200 introduced in 1986
#UNISYS 2200/400 introduced in 1988
#UNISYS 2200/600 introduced in 1989
#UNISYS 2200/100 introduced in 1990
#UNISYS 2200/500 introduced in 1993
#UNISYS 2200/900 introduced in 1993
#UNISYS 2200/3800 introduced in 1997
==UNISYS ClearPath IX series==
In 1996Unisys Corporation introduces the ClearPath IX series.
==External links==
*[http://www.fourmilab.ch/documents/univac/ UNIVAC® Memories]
*[http://people.cs.und.edu/~rmarsh/CLASS/CS451/HANDOUTS/os-unisys.pdf A history of Univac computers and Operating Systems] (PDF file)
Mainframe computers