IBM System/360 Model 65
The IBM System/360 Model 65 is a member of the IBM System/360 family of computers. It was announced April of 1965, and replaced two models, the Model 60 and Model 62, announced one year prior but never shipped.[1]
Features

The Model 65 implements the complete System/360 "universal instruction set" architecture, including floating-point, decimal, and character operations as standard features. It offered optional compatibility features to permit emulation of the IBM 7040 and 7044 and the IBM 7090 and 7094,[2] the IBM 7070 and 7074,[3] and the IBM 7080.[4]
The system comes with five sizes of core memory. The G65, H65, I65, IH65 and J65 submodes are configured with 128K, 256K, 512K, 768K or 1M of core memory, respectively.[5] Main memory in the Model 65 can be interleaved for faster access.[5]
The Model 65, like the Model 67, was available in a dual-CPU offering. Multi-processing (Dual-CPU) systems are comprised of two I65s, IH65s or J65s, and "the main storage of each processing unit is accessible to the other."[5]
Relative performance
The performance of the Model 65 was over triple that of a 360/50, whereas the Model 75, the next step up, was less than double that of a 360/65.[6]
Systems software
OS/360 MVT was a fairly typical choice of operating system for the Model 65.
A special version of MVT was needed for the multi-process (dual CPU) Model, called MP65.[7][8]
Time-sharing
Time-sharing could be provided on a Model 65 using IBM's Time Sharing Option (TSO).[9]
See also
- Museum: The Smithsonian Institution has a System/360 Model 65.[10]
References
- ^ Pugh, Emerson; et al. (1991). "Appendix A - System Introduction Dates 1964-1977". IBM's 360 and Early 370 Systems. MIT.
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suggested) (help) - ^ IBM System/360 Special Feature Description-709/7040/7044/7090/7094 II Compatibility Feature for IBM System/360 Models 65 and 67. IBM. A27-2715.
- ^ IBM System/360 Special Feature Description-7074 Compatibility Feature for System/360 Models 50 and 65. IBM. A27-2717.
- ^ IBM System/360 Special Feature Description-7080 Compatibility Feature for System/360 Model 65. IBM. A21-2116.
- ^ a b c IBM System/360 Model 65 Punctional Characteristics (PDF). September 1968. A22-6884-3.
- ^ Padegs, A. (September 1981). "System/360 and Beyond". IBM Journal of Research and Development. 25 (5). IBM: 377–390. doi:10.1147/rd.255.0377.
- ^ Dave Morton (September 2011). "IBM Mainframe Operating Systems: Timeline and Brief ExplanationFor the IBM System/360 and Beyond". Retrieved September 19, 2016.
- ^ it used special CPU-to-CPU/Multisystem mode instructions, such as Write Direct
- ^ IBM System/360 Operating System: Time Sharing Option Guide (PDF). IBM. July 1972. GC28-6698.
- ^ System/360#Remaining machines