IBM System/360 Model 85
The IBM System/360 Model 85 was a high end system that was introduced in January, 1968, with many advanced features. IBM built only about 30 360/85 systems[1] because of "a recession in progress."
Models
The four offered models of the 360/85[2] were: I85 (512K), J85 (1M), K85 (2M) and L85 (4M), configured with 2 2365 Processor Storage units, 4 2365 units, an IBM 2385 Processor Storage unit Model 1 (=2M), or an IBM 2385 Processor Storage unit Model 2 (=4M) respectively. The I85 includes two-way interleaving while the others provide four-way interleaving of memory access.
Advanced/special features
- The system console was L-shaped: one leg was the "Main Control Panel, including a CRT, and the other leg included 2 screens: "Microfiche Document Viewer" and "Indicator Viewer."[2]:p.8
- Memory Cache - depending on the model and the situation, "the effective system storage cycle becomes one-third to one-fourth of the actual main storage cycle."[2]:p.5
- enhanced floating point - IBM offered extended-precision 128-bit quadruple-precision floating point on the 360/85[3]
Emulation
The 360/85, with the use of an emulator program and special instructions, permits running 709, 7040, 7044, 7094 and 7094 II programs.[2]:p.9
Gateway to the future
The 360/85 used microcode to control instruction execution,[4] unlike the completely-hardwired 360/75 and 360/91; the high-end models of System/370 were also microcoded. Some describe the 360/85 as a bridge to the 370/165.[5]
See also
- IBM System/360 Model 20
- IBM System/360 Model 22
- IBM System/360 Model 25
- IBM System/360 Model 30
- IBM System/360 Model 40
- IBM System/360 Model 44
- IBM System/360 Model 50
- IBM System/360 Model 65
- IBM System/360 Model 67
- IBM System/360 Model 91
References
- ↑ Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H. (1991). IBM's 360 and Early 370 Systems. Cambridge: MIT Press. p. 419. ISBN 0-262-16123-0.
- 1 2 3 4 "IBM System/360 Model 85 Functional Characteristics" (PDF). IBM. June 1968. A22-6916-1.
- ↑ and other high-end 360 models; IBM Floating Point Architecture
- ↑ Robert L. Asenhurst. Foundations of Microprogramming. p. 34. ISBN 1483215873.
- ↑ Jon Elson (December 5, 2014). "IBM 360/85 vs. 370/165". Newsgroup: alt.folklore.computers.