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IBM System/370 Model 155

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This is an old revision of this page, as edited by Pi314m (talk | contribs) at 07:11, 28 December 2016 (→Growth path: /* IBM's description is about the new 370; the 360 is a reference point). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
ManufacturerInternational Business Machines Corporation (IBM)
Product familySystem/370
TypeModel 155
Release dateJune 30, 1970 (1970-06-30)
DiscontinuedDecember 23, 1977
WebsiteOfficial website IBM Archives
3 months after the announcement of
the 370/155 (and 165)
came the Model 145.[1]
Unlike the 155 (or 165),
the 145's lack of virtual memory could be rectified with a simple microcode update from a floppy disk, vs the others needing a hardware upgrade.
The IBM 3330
Direct Access Storage Facility,
code-named Merlin, was introduced in June 1970 for use with the IBM System/370. Its removable disk packs could hold 100 MB

The IBM System/370 Model 155 (and the Model 165),[2] were jointly announced Jun 30, 1970[3] as "designed for ... the Seventies." That same day IBM announced the 370/195.[4] They were the first three models of the IBM System/370 line of computers.

Three months later a fourth IBM System/370, the Model 145, was announced. Since none of them came with virtual memory, "which was to be a hallmark of the 370 line"[5] some said about these early members, of the IBM System/370 family, especially about the 165 & 155, that they were not "the real 370 line."[NB 1]

Limitations

Some said about these early members of the IBM System/370 family, looking back, that they were not "the real 370 line" because "neither offered virtual storage capability, which was to be a hallmark of the 370 line."[6]

The 370/155 was described as able to "run under DOS." Both the 155 and the larger 370/165 could "run under OS/360." Neither machine, as announced, could run a virtual memory operating system.

Growth path

The initially announced systems were in many ways merely improved IBM 360 systems. Both were announced as running 360 Operating Systems.[NB 2] No mention was made of virtual memory or new operating systems.

The IBM System/370's basic architecture was described as having been "extended, but not redesigned" from that of IBM System/360.[2]

Upgrade option

In 1972 an upgrade option was announced "to provide the hardware necessary to operate in a virtual memory mode."[7]

Unlike the IBM System/370 Model 145, which as early as June 1971 could have virtual memory capability added to it with a simple microcode update from a floppy disk, the Model 155 and Model 165 needed expensive hardware additions - $200,000 for the 155 and $400,000 for the 165 - to add virtual memory capability, and even this had to wait until 1972, at which time their upgraded 155 was known as an IBM System/370 Model 155-II.[8]

See also

Notes

  1. ^ The 195 was noted as "at the time of its introduction, ... IBM's most powerful computing system" and the 145's microcode could be upgraded from a floppy disk. By contrast, the 155 & 165 needed a hardware addition priced at $200,000 and $400,000 respectively
  2. ^ DOS on the 155, MFT or MVT on either machine

References

  1. ^ "System/370 Model 145". IBM Archives. IBM.
  2. ^ a b "System/370 Model 165". IBM Archives. IBM.
  3. ^ "System/370 Model 155". IBM Archives. IBM.
  4. ^ coming about 14 months after the announcement of the 360/195. Both 195 machines were withdrawn Feb. 9, 1977. see https://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP2195.html and https://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP3195.html
  5. ^ "What Course for the 3081?". Computerworld. November 24, 1980. p. 34.
  6. ^ "What Course for the 3081?". Computerworld. November 24, 1980. p. 34.
  7. ^ "First IBM DAT Box Installed". Computerworld. August 15, 1973. p. 17.
  8. ^ A. Padegs (September 1981). "System/360 and Beyond". IBM Journal of Research & Development. 25 (5). IBM: 377–390. doi:10.1147/rd.255.0377. – tables include model characteristics (Table 1) and announcement/shipment dates (Table 2). The S/370-155-II and -165-II are listed under the former but not the latter, because the upgraded systems were not formally announced as separate models. The "System/370 Advanced Function" announcement, including the -158 and -168, was the main public event.
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