3B Computers
Encyclopedia
AT&T Computer Systems
AT&T Computer Systems is the generic name for American Telephone & Telegraph's unsuccessful attempt to compete in the computer business. In return for divesting the local Bell Operating Companies , AT&T was allowed to have an unregulated division to sell computer hardware and software.Prior to the...
's Western Electric
Western Electric
Western Electric Company was an American electrical engineering company, the manufacturing arm of AT&T from 1881 to 1995. It was the scene of a number of technological innovations and also some seminal developments in industrial management...
subsidiary.
High-availability processors
The original series of 3B computers include the models 3B20C, 3B20D, 3B21D, and 3B21E.The 3B (3B20D/3B20C/3B21D/3B21E) is a 32-bit microprogrammed duplex (redundant
Redundancy (engineering)
In engineering, redundancy is the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe....
) high availability
High availability
High availability is a system design approach and associated service implementation that ensures a prearranged level of operational performance will be met during a contractual measurement period....
processor unit with a real-time operating system
Real-time operating system
A real-time operating system is an operating system intended to serve real-time application requests.A key characteristic of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is jitter...
. It is used in the telecommunications environment and was first produced in the late 1970s at the WECo
WECO
WECO may refer to:* Western Electric Company* Winnipeg Electric Company* WECO , a radio station licensed to Wartburg, Tennessee, United States* WECO-FM, a radio station licensed to Wartburg, Tennessee, United States* WECO Lab...
factory in Lisle, Illinois. It uses the Duplex Multi Environment Real Time (DMERT) operating system which was renamed UNIX-RTR (Real Time Reliable) in 1982. The Data Manipulation Unit (DMU) provided arithmetic and logic operations on 32 bit words using AMD 2901 bipolar 4-bit processor elements.
The first 3B20D was called the Model 1. Each processor's control unit consisted of 2 frames of circuit packs. The whole duplex system required many seven foot frames of circuit packs plus
at least one tape drive frame (most telephone companies wrote billing data on magnetic tapes), and many washing machine sized (and look with the open top door) disk drives. For training and lab purposes a 3B20D could be divided into two "half-duplex" systems. A 3B20S
consisted of most of the same hardware as a half-duplex but used a completely different
operating system.
The 3B20C was briefly available as a high-availability fault tolerant multiprocessing
Multiprocessing
Multiprocessing is the use of two or more central processing units within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them...
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
High availability
High availability is a system design approach and associated service implementation that ensures a prearranged level of operational performance will be met during a contractual measurement period....
. It consisted of a virtual "emulated" 3B20D environment running
on a stand-alone general purpose computer (the system was ported to many computers but primarily runs of the Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
Solaris (operating system) environment.
There have been many improvements made to the 3B20D UNIX-RTR system in both software and hardware throughout the 1980s, 1990s, and 2000s. These included some remarkable features such as disk independent operation (DIOP: the ability to continue essential software processing
such as telecommunications after duplex failure of redundant essential disks) and Off-line Boot (the ability to split in half, boot up the previously out-of-service half, verify successful boot), and Switch Forward (switch processing to the previously out-of-service half).The processor was re-engineered and renamed in 1992 as the 3B21D. It is still in use as of 2010 as a component of many Alcatel-Lucent
Alcatel-Lucent
Alcatel-Lucent is a global telecommunications corporation, headquartered in the 7th arrondissement of Paris, France. It provides telecommunications solutions to service providers, enterprises, and governments around the world, enabling these customers to deliver voice, data, and video services...
products such as the 4ESS and 5ESS.
General-purpose computers
The general purpose family of 3B computer systems includes the 3B2, 3B5, 3B15, 3B20S, and 3B4000.These computers were named after the successful 3B20D. The 3B20S (simplex) ran using the UNIX
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
operating system and was developed at Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...
and produced by WECo
WECO
WECO may refer to:* Western Electric Company* Winnipeg Electric Company* WECO , a radio station licensed to Wartburg, Tennessee, United States* WECO-FM, a radio station licensed to Wartburg, Tennessee, United States* WECO Lab...
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
UNIX System V
Unix System V, commonly abbreviated SysV , is one of the first commercial versions of the Unix operating system. It was originally developed by American Telephone & Telegraph and first released in 1983. Four major versions of System V were released, termed Releases 1, 2, 3 and 4...
from AT&T.
3B20S
The 3B20S was built using virtually the same hardware as the 3B20D. The machine was approximately the size of a refrigerator.3B2
Floppy disk controller
A floppy disk controller is a special-purpose chip and associated disk controller circuitry that directs and controls reading from and writing to a computer's floppy disk drive . This article contains concepts common to FDCs based on the NEC µPD765 and Intel 8072A or 82072A and their descendants,...
(nicknamed the "floppy tape"). The 3B2/600 offered an improvement in performance and capacity. It featured a SCSI
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
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 3xx, 4xx and later 500 models). Early models used an internal Emulex card to interface the SCSI controller with ESDI disks, with later models using SCSI drives directly. 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 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.
3B5
The 3B5 was built using the older 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, though adding the reel-to-reel tape drive increased it to the size of a refrigerator.These computers used SMD
Storage Module Device
Storage Module Device was a family of storage devices first shipped by Control Data Corporation in December 1973 as the CDC 9760 40 MB storage module disk drive. The CDC 9762 80 MB variant was announced in June 1974 and the CDC 9764 150 MB and the CDC 9766 300 MB variants were announced in 1975...
hard drives.
3B1 desktop workstation
The 3B13b1
The 3B1 was a Unix workstation computer originally developed by Convergent Technologies , and marketed by AT&T in the mid- to late-1980s...
, also known as the PC7300 or UNIX PC, was a desktop
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...
workstation
Workstation
A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems...
computer based on the Motorola
Motorola
Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...
MC68010 microprocessor, running an operating system from Convergent Technology (based on Unix System V Release 2).
In spite of the labeling and common AT&T heritage, the 3B1 was essentially unrelated in hardware or software to the 3B2 line.
External links
See also
- AT&T Computer SystemsAT&T Computer SystemsAT&T Computer Systems is the generic name for American Telephone & Telegraph's unsuccessful attempt to compete in the computer business. In return for divesting the local Bell Operating Companies , AT&T was allowed to have an unregulated division to sell computer hardware and software.Prior to the...
- 4ESS switch4ESS switchThe 4ESS switch is a Class 4 telephone Electronic Switching System that was the first digital electronic toll switch introduced by Western Electric for long distance switching. It was introduced in 1976 in Chicago, Illinois to replace the 4a crossbar switch. The last of 145 in the AT&T network was...
- 5ESS switch5ESS SwitchThe 5ESS Switch is a Class 5 telephone electronic switching system sold by Alcatel-Lucent. This digital central office telephone circuit switching system is used by many telecommunications service providers.-History:...
switching system - WE32100 microcomputer
- DMERT operating system
- J. O. Becker, The 3B20D PROCESSOR and DMERT Operating System (The Bell System Technical JournalBell System Technical JournalThe Bell System Technical Journal was the in-house scientific journal of Bell Labs that was published from 1922 to 1983.- Notable papers :...
, January 1983, Vol. 62, No. 1, Part 1)