Editing 3B series computers (section)

==History==
The first 3B20D was installed in [[Fresno, California]] at Pacific Bell in 1981.<ref>{{cite journal |last1=Gill |first1=R. J. |last2=Kujawinski |first2=G. J. |last3=Stredde |first3=E. H. |title=Traffic Service Position System No. 1B : Real-Time Architecture Utilizing the DMERT Operating System |journal=Bell System Technical Journal |date=March 1983 |volume=62 |issue=3 |pages=775–826 |doi=10.1002/j.1538-7305.1983.tb04418.x |url=https://bitsavers.computerhistory.org/magazines/Bell_System_Technical_Journal/BSTJ_V62N03_198303_Part_3.pdf |access-date=1 March 2025}}</ref> Within two years, several hundred were in place throughout the [[Bell System]]. Some of the units came with "small, slow hard disks".<ref name=3B2.HC84>{{cite magazine |magazine=[[HARDCOPY]] 
|title=The Unix Connection: 3B2
|author=Walter Zintz |date=July 1984 |page=142}}</ref>

The general purpose family of 3B computer systems includes the 3B2, 3B5, 3B15, 3B20S, and 3B4000. They run the AT&T [[UNIX]] operating system and were named after the successful 3B20D High Availability processor.

In 1984, after regulatory constraints were lifted, AT&T introduced the 3B20D, 3B20S, 3B5, and 3B2 to the general computer market,<ref name=3Bseries.NYT840328/><ref name=":0">{{cite news |last=Mankowski |first=Cal |date=March 27, 1984 |title=AT&T introduces new computer line |newspaper=UPI |url=https://www.upi.com/Archives/1984/03/27/ATT-introduces-new-computer-line/5640449211600/}}</ref> a move that some commentators saw as an attempt to compete with [[IBM]].<ref name="unixreview198802_olivetti">{{cite magazine |last1=Faden |first1=Michael |date=February 1988 |title=Olivetti: Biting the Hand that Feeds It? |url=https://archive.org/details/sim_unix-review_1988-02_6_2/page/9/mode/1up |magazine=UNIX Review |pages=14, 16, 20, 22–23 |access-date=17 August 2022 |via=Internet Archive}}</ref> In Europe, the 3B computers were distributed by Italian firm [[Olivetti computers|Olivetti]], in which AT&T had a minority shareholding.<ref name=":0" /><ref name="unixreview198802_olivetti" /> After AT&T bought NCR Corporation, effective January 1992, the computers were marketed through NCR sales channels.<ref name="lastunits" />

Having produced 70,000 units, the AT&T Oklahoma City plant stopped manufacturing 3B machines at the end of 1993, with the 3B20D to be the last units manufactured.<ref name="lastunits">{{cite news |last1=Denton |first1=Jon |title=AT&T Makes Last 3B2 City-Produced Computer Stuff of Legends |url=https://www.oklahoman.com/story/news/1993/12/16/att-makes-last-3b2-city-produced-computer-stuff-of-legends/62439711007/ |publisher=The Oklahoman |date=December 16, 1993}}</ref>