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 IBM System/360 Model 40 at the USDA | |
| Manufacturer | International Business Machines Corporation (IBM) |
|---|---|
| Product family | System/360 |
| Released | April 7, 1964 (1964-04-07) |
| Discontinued | October 7, 1977 (1977-10-07) |
| Memory | 16–128 KB Core |
TheIBM System/360 Model 40 was a mid-range member of theIBM System/360 family. It was announced on April 7, 1964, shipped in 1965, and withdrawn on October 7, 1977.[1][2]
On April 7, 1964, IBM announced theIBM System/360, to be available in six models.[3][4][5] The 360/40 was first delivered in April 1965.[6]
The360/30 and the 360/40 were the two largest revenue producingSystem/360 models,[7] accounting for over half of the units sold.[8]
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 ofcore memory and correspondingly 16, 32, 64, 128 and 128[NB 1] multiplexer subchannels.[9]
The H40 occupied "more floor space than the other models."[9]: p.5
| A typical, early, basic Model 40 system had the following configuration:[10] | |
|---|---|
| Model 40 processor | IBM 2040 Central Processing Unit *128 KB byte storage *storage protection feature *universal instruction set *one multiplexor channel *two selector channels *interval timer |
| Operator console | IBM 1052 Typewriter- Keyboard (usually assigned to 009 hexadecimal address) |
| Unit record device | IBM 1442 Card Reader-Punch (00A) or IBM 2540 Reader-Punch (00C & 00D) |
| Line printer | IBM 1443 Printer (00B) or IBM 1403 Printer (00E) |
| Disk storage | IBM 2311 Magnetic Disk Drives (190 & 191) or IBM 2314 Direct Access Storage Facility |
| Tape storage | IBM 2401 Magnetic Tape Units (180 & 181 for 7-track, and 182 & 183 for 9-track) |
| Telecommunications controller (If used in a telecommunications environment) | IBM 2701 Communication Controller |
Like most System/360 models the Model 40 ismicroprogrammed. The microcode is stored intransformer read-only storage (TROS), organized as up to 8192 words of 56 bits each. Standard microcode consists of up to 4096 words. The additional 4096 words are used for the 1401 or 1410 compatibility feature.[11]
With the additional Compatibility Feature hardware and Compatibility Support software under DOS/360, theIBM 1401/1440/1460 object programs can be run in the emulation mode, with little or no reprogramming.[12]
Although the cover of IBM's MVT Guide[13] indicates that even a 360/40 could run MVT,the IBMoperating system used was usually the realistically sizedDOS/360,[citation needed] because all but one model of the 360/40 had less than MVT's minimum memory requirements of 256KB.[14][15]
The IBM System/360 Model 40 was developed atIBM Hursley[16] and manufactured at IBM's facilities in Poughkeepsie, New York,Mainz, Germany; andFujisawa, Japan.[17]
A modified Model 40 ranCP-40, the ancestor ofCP/CMS, which in turn was the progenitor of theVM line.
Mike Flinders, who also worked at Hursley where the 360/40 was designed
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