IBM System/370 Model 155: Difference between revisions

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Growth path: The initial pre-virtual-memory features introduced by S/370 should be, and now are, discussed in the IBM System/370 article.
Upgrade option: Rephrase a bit to make the tone more encyclopedic and to put a footnote inline.
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In 1972 an upgrade option was announced "to provide the hardware necessary to operate in a virtual memory mode."<ref>{{cite newspaper|newspaper=Computerworld|date=August 15, 1973|page=17|title=First IBM DAT Box Installed|url=https://books.google.com/books?id=T3qky0Z-gc0C&pg=PA17#v=onepage&q&f=false}}</ref>
 
Unlike the [[IBM System/370 Model 145]] customers, whowhich as early as June 1971 werecould ablehave tovirtual merelymemory addcapability virtualadded memoryto capabilityit with a simple [[microcode]] update from a floppy disk, those using what literature of the dayModel at155 timesand calledModel a165 "boatneeded anchor"expensive (ifhardware leftadditions as-is) needed to purchase expensive hardware<ref group="NB">$200,000 for the 155 and $400,000 for the 165</ref> - to upgradeadd theirvirtual machinesmemory 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.<ref>{{cite journal | author = A. Padegs | title = System/360 and Beyond | journal = IBM Journal of Research & Development | volume = 25 | issue = 5 | pages = 377–390 |date=September 1981 | publisher = IBM | doi = 10.1147/rd.255.0377}} &ndash; 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.</ref>