IBM 7090: Difference between revisions

{{Use American English|date=February 2023}}

{{Use mdy dates|date=February 2023}}

The '''IBM 7090''' is a second-generation [[Transistor computer|transistorized]] version of the earlier [[IBM 709]] vacuum tube [[mainframe computer]] that was designed for "large-scale scientific and technological applications". The 7090 is the fourth member of the [[IBM 700/7000 series#Scientific Architecture|IBM 700/7000 series]] scientific computers. The first 7090 installation was in December 1959.<ref>IBM states "the first 7090 was installed in December, 1959" at [https://www.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP7090.html 7090 Data Processing System]</ref> In 1960, a typical system sold for $2.9 million (equivalent to ${{Inflation|US-GDP|2.9|1960|r=0}}&nbsp;million in {{Inflation-year|US}}) or could be rented for $63,500 a month ({{Inflation|US-GDP|63500|1960|r=-3|fmt=eq}}).

 

The 7090 uses a [[36-bit]] [[word length]], with an address space of 32,768 words (15-bit addresses).<ref name="comp-arch-n-org">{{cite book |title=Computer Architecture and Organization |last1=Hayes |first1=John.P |isbn=0-07-027363-4 |date=1978 |page=33}}</ref> It operates with a basic memory cycle of 2.18 μs, using the [[IBM 7302]] Core Storage [[Magnetic-core memory|core memory]] technology from the [[IBM 7030]] (Stretch) project.

 

 

==Development and naming==

 

===IBM 7094===

<!-- If there are incompatibilities, please cite sources. -->

Although the 7094 has four more index registers than the 709 and 7090, at power-on time it is in ''multiple tag mode'',<ref name=IBM7094>{{cite manual|url=http://bitsavers.org/pdf/ibm/7094/A22-6703-4_7094_PoO_Oct66.pdf|title=IBM 7094 Principles of Operation|id=A22-6703-4|date=October 21, 1966|publisher=IBM}}</ref>{{rp|8}} compatible with the 709 and 7090, and requires a '''Leave Multiple Tag Mode'''<ref name=IBM7094/>{{rp|56}} instruction in order to enter ''seven index register mode'' and use all seven index registers. In multiple tag mode, when more than one bit is set in the tag field, the contents of the two or three selected index registers are logically [[Bitwise operation#OR|ORed]], not [[Binary number#Addition|added]], together, before the decrement takes place. In seven index register mode, if the three-bit tag field is not zero, it selects just one of seven index registers, however, the program can return to multiple tag mode with the instruction '''Enter Multiple Tag Mode''',<ref name=IBM7094/>{{rp|55}} restoring 7090 compatibility.

 

==Input/output==

The 7090 series features a data channel architecture for input and output, a forerunner of modern [[direct memory access]] I/O. Up to eight data channels can be attached, with up to ten [[IBM 729]] tape drives attached to each channel. The data channels have their own very limited set of operations called commands. These are used with tape (and later, disk) storage as well as card units and printers, and offered high performance for the time. Printing and [[punched card]] I/O, however, employed the same modified [[unit record equipment]] introduced with the 704 and was slow. It became common to use a less expensive [[IBM 1401]] computer to read cards onto [[magnetic tape]] for transfer to the 7090/94. Output would be written onto tape and transferred to the 1401 for printing or card punching using its much faster peripherals, notably the [[IBM 1403]] line printer.

 

 

*The [[Compatible Time-Sharing System]] (CTSS), the first general purpose [[time-sharing]] operating system,<ref>{{cite report |last1=Singh |first1=Jai P. |last2=Morgan |first2=Robert P. |date=October 1971 |title=Educational Computer Utilization and Computer Communications |url=https://files.eric.ed.gov/fulltext/ED057575.pdf |publisher=Washington University |location=St. Louis, MO |id=National Aeronautics and Space Administration Grant No. Y/NGL-26-008-054 |page=13 |access-date=March 8, 2022 |quote=Much of the early development in the time-sharing field took place on university campuses.⁸ Notable examples are the CTSS (Compatible Time-Sharing System) at MIT, which was the first general purpose time-sharing system...}}</ref> developed at [[Massachusetts Institute of Technology|MIT]]'s Computation Center on three successive computers, an IBM 709, 7090 and 7094 with [[Request price quotation|RPQs]] for additional features. It eventually ran on two separate 7094s, one of them at [[MIT Computer Science and Artificial Intelligence Laboratory#Project MAC|Project MAC]].<ref>{{cite web |url=https://people.csail.mit.edu/saltzer/Multics/CTSS-Documents/RPQs/RPQs.html |title=IBM 7094 Hardware Modifications for CTSS (RPQs) |author=<!--Not stated--> |date=n.d. |publisher=[[Massachusetts Institute of Technology]] |access-date=March 29, 2022}}</ref><ref name=7094CTSS>[http://multicians.org/thvv/7094.html The IBM 7094 and CTSS] Also contains links to many original CTSS documents</ref><ref name="ctsspg69">{{cite web |url=http://www.bitsavers.org/pdf/mit/ctss/CTSS_ProgrammersGuide_Dec69.pdf |title=The Compatible Time-Sharing System, A Programmer's Guide |editor-last=Crisman |editor-first=P.A. |date=December 31, 1969 |publisher=The M.I.T Computation Center |access-date=March 10, 2022}}</ref>

*[[NASA]] used 7090s, and, later, 7094s to control the [[Project Mercury|Mercury]] and [[Project Gemini|Gemini]] space flights. [[Goddard Space Flight Center]] operated three 7094s. During the early [[Project Apollo|Apollo Program]], a 7094 was kept operational to run flight planning software that had not yet been ported to mission control's newer [[System/360]] computers. {{Citation needed|date=June 2010}}

*Caltech/NASA [[Jet Propulsion Laboratory]] had three 7094s in the Space Flight Operations Facility (SFOF, building 230), fed via tape using several 1401s, and two 7094/7044 direct-coupled systems (in buildings 125 and 156). {{underdiscussion-inline|Re: Notable applications: JPL}}