{{Short description|Computers manufactured by General Electric}} The '''GE/PAC 4000''' computer systems are an obsolete line of computers manufactured by General Electric in Phoenix, Arizona beginning in the 1960s. '''PAC''' is short for ''Process Automation Computer'', indicating the intended use of the systems for process control.
All 4000 systems are 24-bit, using fixed-point binary data, with between 1020 and 65,536 words of magnetic core memory, and a magnetic drum memory with 8192 to 262,144 word capacity. The CPU logic is implemented with discrete transistors. The systems can be configured with a wide variety of analog and digital inputs and outputs.<ref name=SysMan>{{cite book |publisher=General Electric Process Computer Business Section |title=GE/PAC 4000 Systems Manual |date=1966 |url=http://bitsavers.org/pdf/ge/PAC-4000/GET-3201B_PAC-4000_SysMan_Mar66.pdf |accessdate=June 7, 2020}}</ref><ref>{{cite book |publisher=General Electric Process Computer Business Section |title=GE/PAC 4000 Programming Manual |date=1965 |url=http://bitsavers.org/pdf/ge/PAC-4000/PCP-102B_PAC4000_Pgmg_Dec65.pdf |accessdate=June 7, 2020}}</ref>
The 4020 is the low-end model of the system.<ref>{{cite web |author=General Electric |title=Industry's most advanced compact computer for process control, GE/PAC 4020 |url=https://www.computerhistory.org/collections/catalog/102640390 |website=Computer History Museum |date=1965 |accessdate=June 9, 2020}}</ref> Three models of the 4000, the 4040, 4050, and 4060 differ in storage speed— 5μsec, 3.4μsec, and 1.7 and 2.38μsec respectively— and by the implementation of a serial arithmetic unit on the 4040 vs. parallel on the other systems,
==Software== The operating system for the 4000 series is called "G-E-MONITOR", a "skeleton real-time system program." "Several versions of MONITOR are available, each tailored to the needs of a specific industry or process." Other software included ''Process Assembler Language'' (PAL), FORTRAN II, and ''Tabular Sequence Control'' (TASC). A set of memory load, dump, and change routines was provided.<ref name=SysMan />{{rp|33–34}}
==Applications== A product brochure highlighted potential uses in the utility industry, food processing, manufacturing, the metal and chemical industry, paper and cement manufacturing, and petroleum.<ref name="SPC">{{cite book |last1=General Electric |title=GE/PAC 4000 Small Process Computer |date=Oct 1963 |url=https://www.vintagecomputer.net/GE/GEPac-4000/GE_GEPac-4000.pdf |accessdate=June 8, 2020}}</ref>
==References== {{Reflist}}
Category:Transistorized computers Category:General Electric Category:24-bit computers
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