 | |
 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 It was announced on April 7, 1964, shipped in 1965, and withdrawn on October 7, 1977.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]
On April 7, 1964, IBM announced the IBM System/360, to be available in six models. [3] [4] [5] The 360/40 was first delivered in April 1965. [6]
The 360/30 and the 360/40 were the two largest revenue producing System/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 of core 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 was microprogrammed. The microcode was stored in transformer read-only storage (TROS), organized as up to 8192 words of 56 bits each. Standard microcode consisted of up to 4096 words. The additional 4096 words were used for the 1401 or 1410 compatibility feature. [11]
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. [12]
Although the cover of IBM's MVT Guide [13] 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. [14] [15]
The IBM System/360 Model 40 was developed at IBM Hursley [16] and manufactured at IBM's facilities in: Poughkeepsie, U.S., Mainz, Germany; and Fujisawa, Japan. [17]
A modified Model 40 ran CP-40, the ancestor of CP/CMS, which in turn was the progenitor of the VM line.
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The IBM System/360 (S/360) is a family of mainframe computer systems that was announced by IBM on April 7, 1964, and delivered between 1965 and 1978. It was the first family of computers designed to cover both commercial and scientific applications and a complete range of applications from small to large. The design distinguished between architecture and implementation, allowing IBM to release a suite of compatible designs at different prices. All but the only partially compatible Model 44 and the most expensive systems use microcode to implement the instruction set, featuring 8-bit byte addressing and fixed point binary, fixed point decimal and hexadecimal floating-point calculations.
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Mike Flinders, who also worked at Hursley where the 360/40 was designed
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