33:
304:
drivers for SCSI (APEs) and serial boards (ACEs). The processing boards are interconnected by a redundant low latency parallel bus (ABUS) running at 20 MB/s. The UNIX kernels running on the adjunct processors are modified to allow the fork/exec of processes across processing units. The system calls and peripheral drivers are also extended to allow processes to access remote resources across the ABUS. Since the ABUS is hot-swappable, processors can be added or replaced without shutting down the system. If one of the adjunct processors fails during operation, the system can detect and restart programs that were running on the failed element.
951:
321:
334:
342:
189:
There were improvements to the 3B20D UNIX-RTR system in both software and hardware in the 1980s, 1990s, 2000s, and 2010s. Innovations included disk independent operation (DIOP: the ability to continue essential software processing such as telecommunications after duplex failure of redundant essential
178:
general-purpose computer in the commercial market in 1984. The 3B20E was created to provide a cost-reduced 3B20D for small offices that did not expect such high availability. It consists of a virtual "emulated" 3B20D environment running on a stand-alone general purpose computer; the system was ported
408:
The 3B2/500 was the next model to appear, essentially a 3B2/600 with enough components removed to fit into a 400 case; one internal disk drive and several backplane slots are sacrificed in this conversion. Unlike the 600, which because of its two large fans is loud, the 500 is tolerable in an office
400:
controller for the 60 MB QIC tape and two internal full-height disk drives. The 600 is approximately twice as tall as a 400, and is oriented with the tape and floppy disk drives opposite the backplane (instead of at a right angle to it as on the 3xx, 4xx and later 500 models). Early models use an
303:
Indian Hill West facility by the High
Performance Computer Development Lab, the system consists of multiple high performance (at the time) processor boards – adjunct processing elements (APEs) and adjunct communication elements (ACEs). These adjunct processors run a customized UNIX kernel with
298:
server introduced in 1987 and based on a 'snugly-coupled' architecture using the WE series 32x00 32-bit processor. Known internally as 'Apache', the 3B4000 is a follow-on to the 3B15 and initial revisions use a 3B15 as a master processor. Developed in the mid-1980's at the
163:. The first 3B20D is called the Model 1. Each processor's control unit consists of two frames of circuit packs. The whole duplex system requires seven-foot frames of circuit packs plus at least one tape drive frame (most telephone companies at that time wrote billing data on
269:
32-bit microprocessor. The initial versions have discrete memory management unit hardware using gate arrays, and support segment-based memory translation. I/O is programmed using memory-mapped techniques. The machine is approximately the size of a
307:
The 3B4000 is capable of significant expansion; one test system (including storage) occupies 17 mid-height cabinets. Generally, the performance of the system increases linearly with additional processing elements, however the lack of a true
364:
The 300 was soon supplanted by the 3B2/310 running at 10 MHz, which features the WE 32100 CPU as do later models. The Model 400, introduced in 1985, allows more peripheral slots and more memory, and has a built-in 23 MB
190:
disks); off-line boot (the ability to split in half and boot the out-of-service half, typically on a new software release) and switch forward (switch processing to the previously out-of-service half); upgrading the disks to
171:-sized disk drives. For training and lab purposes, a 3B20D can be divided into two "half-duplex" systems. A 3B20S consists of most of the same hardware as a half-duplex but uses a completely different operating system.
90:
In 1984, after regulatory constraints were lifted, AT&T introduced the 3B20D, 3B20S, 3B5, and 3B2 to the general computer market, a move that some commentators saw as an attempt to compete with
412:
The 3B2/700 is an uprated version of the 600 featuring a slightly faster processor (WE 32200 at 22 MHz), and the 3B2/1000 is an additional step in this direction (WE 32200 at 24 MHz).
361:. The 3B2 Model 300, which can support up to 18 users, is approximately 4 inches (100 mm) high and the 3B2 Model 400 is approximately 8 inches (200 mm) high.
98:, in which AT&T had a minority shareholding. After AT&T bought NCR Corporation, effective January 1992, the computers were marketed through NCR sales channels.
101:
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.
652:
630:
253:, which was built to replace the man-based messaging system of earlier Olympiads. The system connected around 1800 user terminals and 200 printers. The
643:
J. O. Becker, The 3B20D PROCESSOR and DMERT Operating System (The Bell System
Technical Journal, January 1983, Vol. 62, No. 1, Part 1), Page 193
56:
operating system. The line primarily consists of the models 3B20, 3B5, 3B15, 3B2, and 3B4000. The series is notable for controlling a series of
842:
155:(Real Time Reliable) in 1982. The Data Manipulation Unit (DMU) provides arithmetic and logic operations on 32-bit words using eight
537:
237:
use. The 3B20S has hardware similar to the 3B20D, but one unit instead of two. The machine is approximately the size of a large
748:
514:
206:
879:
578:
83:
The general purpose family of 3B computer systems includes the 3B2, 3B5, 3B15, 3B20S, and 3B4000. They run the AT&T
286:
The 3B15, introduced in 1985, uses the WE 32100 and is the faster follow-on to the 3B5 with similar large form factor.
257:
is an enhanced version of the 3B20S, adding in a second processing unit working in parallel as a multiprocessor unit.
907:
137:
312:
capability requires rewriting applications that rely heavily on this feature to avoid a severe performance penalty.
32:
835:
201:
The processor was re-engineered and renamed in 1992 as the 3B21D. It is still in use as of 2023 as a component of
358:
728:
450:, is tailored for use as a productivity tool in office environments and as an electronic communication center.
64:, for general computing purposes, and for serving as the historical software porting base for commercial UNIX.
491:
374:
600:
894:
828:
57:
709:
979:
808:
183:
125:
396:
The 3B2/600, running at 18 MHz, offers an improvement in performance and capacity: it features a
989:
405:
card to interface the SCSI controller with ESDI disks, with later models using SCSI drives directly.
117:
45:
974:
443:
984:
459:
370:
366:
912:
275:
209:
160:
141:
17:
242:
8:
213:
109:
The original series of 3B computers includes the models 3B20C, 3B20D, 3B21D, and 3B21E.
87:
operating system and were named after the successful 3B20D High
Availability processor.
753:
733:
687:
542:
519:
496:
95:
73:
955:
295:
191:
121:
61:
691:
274:, though adding the reel-to-reel tape drive increases its size. These computers use
679:
427:
180:
129:
49:
869:
861:
422:
320:
300:
175:
168:
133:
790:
76:
at
Pacific Bell. Within two years, several hundred were in place throughout the
665:
439:
353:
32-bit microprocessor at 8 MHz with memory management chips that supports
164:
802:
968:
670:
354:
309:
212:
and the 4ESS and 5ESS switches, which Nokia inherited from AT&T spin-off
683:
874:
241:, requiring a minimum of 170 square feet floor space. It was in use at the
238:
195:
820:
927:
902:
435:
234:
77:
917:
884:
350:
271:
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156:
333:
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and produced by
Western Electric in 1982 for general purpose internal
174:
The 3B20C was briefly available as a high-availability fault tolerant
937:
230:
113:
814:
44:
are a line of minicomputers made between the late 1970s and 1993 by
559:
442:
microprocessor. It runs a derivative of Unix System V Release 2 by
152:
796:
922:
631:"AT&T Makes Last 3B2 City-Produced Computer Stuff of Legends"
402:
373:(nicknamed the "floppy tape"). These three models use standard
94:. In Europe, the 3B computers were distributed by Italian firm
438:
is unrelated in hardware to the 3B line, and is based on the
246:
202:
148:
932:
851:
594:
592:
397:
84:
53:
341:
91:
589:
80:. Some of the units came with "small, slow hard disks".
509:
507:
557:
Walter Zintz (July 1984). "The Unix
Connection: 3B2".
504:
485:
483:
481:
479:
477:
475:
393:
There are also Model 100 and Model 200 3B2 systems.
136:, for telecommunications applications including the
128:. They were first produced in the late 1970s at the
666:"Olympics electronic messaging system demonstrated"
703:
701:
532:
530:
104:
472:
265:The 3B5 is built with the older Western Electric
147:They use the Duplex Multi Environment Real Time (
966:
698:
527:
489:
836:
179:to many computers, but primarily runs on the
653:3B20S Processor System Index and Description
556:
194:(SSD) ; and upgrading the tape unit to
850:
726:
624:
622:
843:
829:
601:"Olivetti: Biting the Hand that Feeds It?"
415:
576:
446:. The system, which is also known as the
349:The 3B2 was introduced in 1984 using the
707:
619:
340:
332:
319:
31:
749:"A.T.&T. Displays Midsize Computer"
579:"AT&T introduces new computer line"
550:
515:"A.T.&T. Addition To Computer Line"
245:, where around twelve 3B20S served the
52:subsidiary, for use with the company's
14:
967:
769:
767:
628:
824:
773:AT&T, Select Code 999-601-311IS,
598:
345:WE 321SB VMEbus Single Board Computer
229:The 3B20S (simplex) was developed at
151:) operating system which was renamed
729:"Computers Introduced At A.T.&T"
572:
570:
538:"Digital Introduces Computer Series"
764:
24:
655:, Western Electric Co., July 1981.
25:
1001:
797:AT&T 3B2/3B5 Computer Systems
784:
727:Calvin Sims (September 3, 1987).
708:Chandler, David (December 1985).
629:Denton, Jon (December 16, 1993).
577:Mankowski, Cal (March 27, 1984).
567:
490:Andrew Pollack (March 28, 1984).
430:in 1985 that is often dubbed the
315:
72:The first 3B20D was installed in
27:AT&T/Bell family of computers
949:
804:AT&T 3B2 400 Computer Review
599:Faden, Michael (February 1988).
219:
775:AT&T UNIX PC Owner's Manual
741:
720:
658:
492:"AT&T Offers Its Computers"
359:Switching Control Center System
105:3B high-availability processors
646:
637:
13:
1:
928:Stromberg-Carlson/Siemens DCO
615:– via Internet Archive.
465:
938:Automatic Electric GTD-5 EAX
895:Electronic switching systems
759:could support up to 80 users
607:. pp. 14, 16, 20, 22–23
58:electronic switching systems
7:
903:Western Electric 1ESS/1AESS
453:
409:environment, like the 400.
251:Electronic Messaging System
36:A 3B15 computer, circa 1997
10:
1006:
678:(11): 113. November 1983.
126:real-time operating system
124:processor units running a
67:
946:
893:
859:
289:
112:These systems are 32-bit
46:AT&T Computer Systems
923:Northern Telecom DMS-100
426:, AT&T introduced a
369:tape drive managed by a
224:
684:10.1109/MC.1983.1654251
444:Convergent Technologies
416:3B1 desktop workstation
281:
860:Early automatic &
811:by TanRu Nomad in 2012
460:Altos Computer Systems
371:floppy disk controller
346:
338:
328:
325:
260:
37:
956:Telephones portal
918:Northern Electric SP1
913:Western Electric 5ESS
908:Western Electric 4ESS
793:at Harte Technologies
420:Officially named the
344:
336:
323:
210:signal transfer point
205:products such as the
35:
885:Western Electric 5XB
880:Western Electric 1XB
710:"The Monthly Report"
390:" hard disk drives.
249:requirements of the
243:1984 Summer Olympics
817:by Seth J. Morabito
357:. Uses include the
337:3B2/300 motherboard
214:Lucent Technologies
42:3B series computers
980:AT&T computers
854:telephone switches
754:The New York Times
734:The New York Times
543:The New York Times
520:The New York Times
497:The New York Times
347:
339:
326:
74:Fresno, California
38:
962:
961:
862:crossbar switches
546:. March 25, 1987.
523:. March 16, 1989.
296:high availability
192:solid-state drive
122:high availability
62:telecommunication
16:(Redirected from
997:
990:32-bit computers
954:
953:
952:
845:
838:
831:
822:
821:
805:
778:
771:
762:
761:
757:. May 10, 1988.
745:
739:
738:
724:
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696:
695:
662:
656:
650:
644:
641:
635:
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633:. The Oklahoman.
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534:
525:
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511:
502:
501:
487:
434:. However, this
428:desktop computer
423:AT&T UNIX PC
389:
388:
384:
381:
294:The 3B4000 is a
181:Sun Microsystems
130:Western Electric
50:Western Electric
21:
1005:
1004:
1000:
999:
998:
996:
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994:
965:
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870:Strowger Switch
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331:
324:A 3B2 model 400
318:
292:
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227:
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176:multiprocessing
169:washing machine
134:Lisle, Illinois
114:microprogrammed
107:
70:
28:
23:
22:
15:
12:
11:
5:
1003:
993:
992:
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982:
977:
975:Alcatel-Lucent
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799:at Unixwiz.net
794:
786:
785:External links
783:
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697:
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563:. p. 142.
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455:
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440:Motorola 68010
417:
414:
330:
327:
317:
316:Microcomputers
314:
291:
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262:
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226:
223:
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165:magnetic tapes
106:
103:
69:
66:
26:
9:
6:
4:
3:
2:
1002:
991:
988:
986:
985:Minicomputers
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981:
978:
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973:
972:
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957:
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671:IEEE Computer
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355:demand paging
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322:
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310:shared memory
305:
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297:
287:
279:
278:hard drives.
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273:
268:
258:
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244:
240:
236:
232:
220:Minicomputers
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187:
186:environment.
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34:
30:
19:
933:Siemens EWSD
875:Panel Switch
815:3B2 Emulator
774:
758:
752:
743:
732:
722:
716:. p. 8.
713:
675:
669:
660:
648:
639:
609:. Retrieved
604:
582:
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363:
348:
306:
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264:
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250:
239:refrigerator
228:
200:
196:CompactFlash
188:
173:
167:), and many
159:4-bit-slice
146:
111:
108:
100:
89:
82:
71:
41:
39:
29:
791:3B2 manuals
714:Unix Review
605:UNIX Review
436:workstation
235:Bell System
132:factory in
78:Bell System
969:Categories
611:August 17,
466:References
272:dishwasher
401:internal
231:Bell Labs
144:systems.
118:redundant
692:47105018
560:HARDCOPY
454:See also
351:WE 32000
267:WE 32000
157:AMD 2901
153:UNIX-RTR
116:duplex (
96:Olivetti
809:YouTube
448:PC-7300
385:⁄
184:Solaris
68:History
777:(1986)
690:
403:Emulex
290:3B4000
688:S2CID
301:Lisle
255:3B20A
247:email
225:3B20S
203:Nokia
149:DMERT
18:3B21D
852:NANP
613:2022
398:SCSI
282:3B15
207:2STP
161:ALUs
142:5ESS
140:and
138:4ESS
85:UNIX
60:for
54:UNIX
40:The
807:on
680:doi
583:UPI
432:3B1
375:MFM
367:QIC
329:3B2
276:SMD
261:3B5
92:IBM
971::
766:^
751:.
731:.
712:.
700:^
686:.
676:16
674:.
668:.
621:^
603:.
591:^
581:.
569:^
540:.
529:^
517:.
506:^
494:.
474:^
216:.
198:.
120:)
48:'
844:e
837:t
830:v
737:.
694:.
682::
585:.
500:.
387:4
383:1
380:+
378:5
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
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