UNIVAC 1100

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.

Architecture

Data Formats

• Fixed-point either integer or fraction
  • 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 (one's 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: 1 sign bit, 8 bit characteristic, 27 bit mantissa
  • Double precision - 72 bits: 1 sign bit, 11 bit characteristic, 60 bit mantissa
• Alphanumeric
  • Fieldata - 6 bits
  • ASCII - 9 bits

Instruction Format

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.

Registers

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.

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).

Early UNIVAC machines with 110x numbers, but not in the 1100 series

These machines had different architectures and word sizes and were not compatible with each other. They all used vacuum tubes and many used drum memory as their main memory.

1. UNIVAC 1101 introduced in 1950.
2. UNIVAC 1102 introduced in 1953.
3. UNIVAC 1103 introduced in 1953.
4. UNIVAC 1104 introduced in 1957.
5. UNIVAC 1105 introduced in 1958.

UNIVAC 1100 series

These machines had a common architecture and word size. They all used transistorized electronics and integrated circuits. Early machines used core memory (the 1110 used plated wire memory) until that was replaced with semiconductor memory in 1975.

1. UNIVAC 1107 introduced in 1962
2. UNIVAC 1108 introduced in 1965
3. UNIVAC 1106 introduced in 1969
4. UNIVAC 1110 introduced in 1970
5. UNIVAC 1100/10 redesignation of UNIVAC 1106 in 1975
6. UNIVAC 1100/20 redesignation of UNIVAC 1108 in 1975
7. UNIVAC 1100/40 redesignation of UNIVAC 1110 in 1975
8. UNIVAC 1100/80 introduced in 1975
9. UNIVAC 1100/80A introduced in 1977
10. UNIVAC 1100/60 introduced in 1979
11. UNIVAC 1100/70 introduced in 1981
12. UNIVAC 1100/90 introduced in 1982

SPERRY 2200 series

In 1983 Sperry Corporation discontinued usage of the name UNIVAC for their products.

1. SPERRY 2200/100 introduced in 1985
2. SPERRY Integrated Scientific Processor introduced in 1985

UNISYS 2200 series

In 1986 Sperry Corporation merges with Burroughs Corporation to become Unisys.

1. UNISYS 2200/200 introduced in 1986
2. UNISYS 2200/400 introduced in 1988
3. UNISYS 2200/600 introduced in 1989
4. UNISYS 2200/100 introduced in 1990
5. UNISYS 2200/500 introduced in 1993
6. UNISYS 2200/900 introduced in 1993
7. UNISYS 2200/3800 introduced in 1997

UNISYS ClearPath IX series

In 1996 Unisys introduced the ClearPath IX series. The ClearPath machines are a common platform that implement either the 1100/2200 architecture (the ClearPath IX series) or the Burroughs large systems architecture (the ClearPath/MCP series). Everything is common except the actual CPUs, which are implemented as ASICs. In addition to the IX (1100/2200) CPUs and the MCP (burroughs large systems) CPU, the architecture had Xeon (and briefly Itanium) CPUs. Unisys' goal was to provide an orderly transition for their 1100/2200 customers to a more modern architecture.

See also

• List of UNIVAC products

External links

• UNIVAC Memories
• A history of Univac computers and Operating Systems (PDF file)
• UNIVAC timeline