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IBM System/360 Model 44

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The IBM System/360 Model 44 was a specialized variation of IBM's System 360 computer architecture designed for scientific and real-time computing and process control.

The Model 44 was announced August 16, 1965 and withdrawn September 24, 1973.[1]

Architecture

The Model 44 lacked the storage-to-storage character and decimal instruction sets of a standard System/360,[2] however an "extended instruction set" feature was available to provide the missing instructions.[1] The machine featured four unique instructions: Chanqe Priority Mask (CHPM), Load PSW Special (LPSX), Read Direct Word (RDDW), and Write Direct Word (WRDW).[2]: p.73  In addition to standard System/360 short and long floating point the system was advertised as having "variable-length precision floating point arithmetic", the ability to use any specified precision up to the full fifteen digits offered by long precision to gain speed.[1]

The system came with four memory sizes: E (32 KiB), F (64 KiB), G (128 KiB), and H (256 KiB), with an access time of 1μsec, which put it closer to the Model 65 (.75μsec) than the Model 50 (2.0μsec).[3]: pp.6-11, 6–12 [1] Storage protection was an optional feature.[4]: p.9 

General purpose registers were normally located in a non-addressable portion of 1μsec core storage termed "bump storage". For added speed, the general purpose registers could be implemented in Solid Logic Technology (SLT) circuitry with an access time of .25μsec.[4]: p.8 

Peripherals

The Model 44 could support up to one standard and two high-speed System/360 multiplexer channels in addition to integrated adapters for the single disk storage and the console 1052 printer/keyboard.[1]

IBM 2315 disk cartridge

A unique feature of the Model 44 was its integrated single disk storage drive which used the IBM 2315 cartridge and provided approximately 1 MiB of removable disk storage built right into the CPU. A second integrated drive was available as an option.[4]: p.12  The Model 44 Programming System (M44PS) used this drive as a systems residence device.[5]: p.7 

Software

The Model 44 Programming System software included a supervisor, utility programs, assembler, FORTRAN IV compiler, and a library of scientific subroutines.[1]

References

  1. ^ a b c d e f IBM Corporation. "IBM Archives: System/360 Model 44". Retrieved October 18, 2012.
  2. ^ a b IBM Corporation (1966). IBM System/3S0 Model 44 Programming System Assembler Language (PDF).
  3. ^ IBM Corporation (1974). IBM System/360 System Summary (PDF).
  4. ^ a b c IBM Corporation. IBM System/360 Model 44 Functional Characteristics (PDF).
  5. ^ IBM Corporatopn (1966). IBM System/360 Model 44 Programming System Concepts and Facilities (PDF).

See also

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