3B series computers

3B is a family of computer systems, produced by Western Electric/AT&T Computer Systems/Lucent Technologies/Alcatel-Lucent.

High Availability Processors

These include: 3B20C, 3B20D, and 3B21D.

The 3B21D is a 32-bit microprogrammed duplex (redundant) processor unit with a real-time operating system. It is used in the telecommunications environment and was first produced in the late 1970s at the WECo factory in Lisle, Illinois. It ran under the Duplex Multi Environment Real Time (DMERT) operating system which was renamed UNIX-RTR (Real Time Reliable) in 1982. The 3B20C was briefly available as a high-availability fault tolerant multiprocessing computer in the commercial market in 1984. There were many improvements in both software and hardware throughout the 1980s. The processor was reengineered and renamed in 1992 as the 3B21D. It is still in use today as a component of many Alcatel-Lucent products such as the 4ESS and 5ESS.

General Purpose Computers

The family includes: 3B2, 3B5, 3B15, 3B20S, and 3B4000.

These computers were named after the successful 3B20D. The 3B20S (simplex) ran using the UNIX operating system was developed at Bell Labs and produced by WECo in 1982 for the general purpose internal Bell System use and later the mini-computer market. The other "3B" computers were also created for this market and eventually were running UNIX System V from AT&T.

The 3B20S was built using AMD 2900 bit-slice processor chips and microprogrammed. The machine was approximately the size of a refrigerator.

The 3B5 was built using the Western Electric WE-32000 32-bit microprocessor. The initial versions had discrete memory management unit hardware built using gate arrays and supported segment-based memory translation. IO was programmed using memory-mapped techniques. The machine was approximately the size of a dishwasher.

The 3B2 was introduced using the WE-32000 32-bit microprocessor with memory management chips that supported demand-paging. The 3B2 Model 300 was approximately 4-inches high and the 3B2 Model 400 was approximately 8-inches high. The 300 was soon supplanted by the 3B2-310, which featured the WE-32100 CPU as did all follow on models. The Model 400 allowed more peripheral slots and more memory. It also had a built-in 24 megabyte QIC tape drive managed by a floppy disk controller (nicknamed the "floppy tape"). The 3B2-600 offered an improvement in performance and capacity. It featured a SCSI controller for the 60 megabyte QIC tape and two internal full-height disk drives. The 600 was approximately twice as tall as a 400, and was oriented with the tape and floppy disk drives opposite the backplane (instead of at a right angle to it as on the 300, 400 and later 500 models). Early models used an internal Emulex card to interface the SCSI controller with ESDI disks. The 3B2-500 was the next model to appear. It was essentially a 600 with enough components removed to fit into a 400 case. One internal disk drive and several backplane slots were sacrificed in this conversion. Unlike the 600 which, because of its two large fans was quite loud, the 500 was tolerable in an office environment, like the 400. The 3B2-700 was an uprated version of the 600 featuring a slightly faster processor. The 3B2-1000 was an additional step in this direction.

3B1

The 3B1 (otherwise known as the PC7300 or UNIX PC) was a desktop workstation computer based on the Motorola MC68010 microprocessor, running an operating system based on Unix System V Release 2.

External links

* [http://www.imsai8080.com/computers/3b2/ 3B2 manuals ]
* [http://www.unixwiz.net/3b2.html AT&T 3B2/3B5 Computer Systems]

ee also

* AT&T Computer Systems
* 4ESS switch
* 5ESS switch switching system
* WE32100 microcomputer
* DMERT operating system
* J. O. Becker, "The 3B20D PROCESSOR and DMERT Operating System" (The Bell System Technical Journal, January 1983, Vol. 62, No. 1, Part 1)