IBM System/360 Model 40
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![]() IBM System/360 Model 40 at the USDA | |
Manufacturer | International Business Machines Corporation (IBM) |
---|---|
Product family | System/360 |
Release date | April 7, 1964 |
Discontinued | October 7, 1977 |
Memory | 16–128 KB Core |
The IBM System/360 Model 40 was a mid-range member of the IBM System/360 family. It was announced on April 7, 1964, shipped in 1965, and withdrawn on October 7, 1977.[1][2]


History
April 7, 1964 was the announcement of the then-new IBM System/360, to be available in six models. The top three (60, 62, 70) were never shipped. The 360/40 was the middle of the three (30, 40, 50), which were delivered (mid to late 1965).[3][4][5][6]
Along with the 360/30, these were the two largest revenue producing System/360 models,[7] accounting for over half the units sold.[8]
Models
Five models of the 360/40 were offered.[9] The D40, E40, F40, G40 and H40 were configured with 16K, 32K, 64K, 128K and 256K of core memory and correspondingly 16, 32, 64, 128 and 128 [10] multiplexer subchannels.[9]
The H40[11] occupied "more floor space than the other models."[9]: p.5
Configuration
A typical, early, basic Model 40 system had the following configuration:[12]
- A Model 40 processor
- IBM 2040 Central Processing Unit
- 128K byte storage, storage protection feature, universal instruction set,
- one multiplexor channel, two selector channels, and interval timer
- An operator console
- IBM 1052 Typewriter- Keyboard (usually assigned to 009 hexadecimal address)
- A unit record input-output machine
- A line printer
- A disk storage
- A tape storage
- IBM 2401 Magnetic Tape Units (180 & 181 for 7-track, and 182 & 182 for 9-track)
If used in a telecommunications environment, the Model 40 also had:
- A telecommunication controller
- IBM 2701 Communication Controller
IBM 1400 series emulation
With the additional Compatibility Feature hardware and Compatibility Support software under DOS/360, the IBM 1401/1440/1460 object programs could be run in the emulation mode, with little or no reprogramming.[13]
Other
Although the cover of IBM's MVT Guide[14] indicates that even a 360/40 could run MVT, the IBM operating system used was usually the realistically sized DOS/360,[citation needed] because all but one model of the 360/40 had less than MVT's minimum memory requirements of 256KB.[15][16]
The IBM System/360 Model 40 was developed[17] and manufactured at IBM's facilities in: Poughkeepsie, U.S., Mainz, Germany; and Fujisawa, Japan.
References
- ^ IBM System/360 Model 40 (IBM Archives)
- ^ IBM System/360 model 40 (Flickr from Yahoo!)
- ^ Emerson W. Pugh. Building IBM: Shaping an Industry and Its Technology. Cambridge, Mass.: MIT Press. p. 275. ISBN 0-262-16147-8.
- ^ From Mainframes to Smartphones, by Martin Campbell-Kelly, Daniel D. Garcia-Swartz; Harvard University Press; ISBN 9780674729063
- ^ "System/360 Dates and characteristics". IBM.
- ^ Fortune magazine, Sept. 1966, p.118
- ^ Pugh, Emerson W.; Johnson,, Lyle R.; Palmer, John H. (1991). IBM's 360 and early 370 systems. Cambridge, Mass.: MIT Press. ISBN 9780262161237.
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(help)CS1 maint: extra punctuation (link) - ^ An ADP Newsletter cited on page 56 in Weiss, Eric A. (ed) (1969). Computer Usage Essentials. McGraw-Hill. LCCN 71-76142.
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has generic name (help) shows sales of the 360 Model 30 (36%) and the Model 40 (22.6%), for a total of 58.6% - ^ a b c IBM System/360 Model 40 Functional Characteristics (PDF). August 1971. A22-6881-2.
- ^ not a typo: the physical limit seemed to be 224; see p. 17 of the Model 30 Functional Characteristics
- ^ as per those IBM 1620 systems with larger amounts of memory; Basic Programming Concepts and The IBM 1620 Computer, by Daniel N. Leeson, Donald L. Dimitry, (C) 1962 by Holt, Rinehart and Winston
- ^ IBM System/360 Model 40 Operating Techniques (PDF). IBM. C20-1635-2.
- ^ IBM System/360 Disk Operating System 1401/1440/1460 Emulator Programs: Compatibility Support/30 & /40 (PDF) (Third ed.). IBM. February 1969. C27-6940-2.
- ^ IBM System/360 Operating System: MVT Guide OS Release 21.7 (PDF). IBM. August 1974. GC28-6720-5.
- ^ IBM System/360 Operating System: Storage Estimates OS Release 21.7 (PDF). IBM. April 1973. GC28-6551-16.
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(help) - ^ Ray Saunders. "MVS... And Before OS/360 ?". Archived from the original on 2007-12-20.
- ^ http://www.cs.man.ac.uk/CCS/res/res23.htm states: "The System/360 architecture was developed in Poughkeepsie, 80 miles north of New York. Contributions came from people all over IBM, including our Hursley development group." and notes specific involvement in developing the 360/40.