AT&T Computer Systems

AT&T Computer Systems is the generic name for AT&T's abortive attempt to enter the computer business. In return for divesting tthe local Bell Operating Companies ("Baby Bells"), AT&T was allowed to have an unregulated division to sell computer hardware and software.

Prior to the divestiture of the Bell system on January 1, 1984, the Bell Labs Processor Division has developed the 3B20D ("D" for Duplex), still the world's most reliable computer; the commercial simplex version 3B20S, which competed with the DEC VAX for internal Bell System usage; the world's first 32-bit microprocessor, the BELLMAC 32A; and, using this microprocessor, the 3B5 and 3B15 for billing and telecomm switching control applications.

After divestiture, AT&T was required to put its computer business into a fully-separated subsidiary called AT&T Information Systems. Software was developed in New Jersey locations (Murray Hill, Summit, Holmdel, and Piscataway), and hardware and system solutions were developed in Naperville and Lisle, IL. After years of court hearings, AT&T was allowed to pull the business back into the mainstream corporate organization, and it was renamed AT&T Data Systems Group, consisting of Computer, Terminals (the old Teletype organization of Skokie, IL), and Printer divisions. Soon afterward, the Terminals division was sold to Memorex-Telex, and the Printer division, which had only bought OEM equipment from Genicom, was phased out. This left only AT&T Computer Systems.

AT&T Computer Systems (abbreviated AT&T-CS) was the home of the UNIX System V Operating System. The important SVID (System V Interface Definition) was written, attempting to standardize the various flavors of UNIX. AT&T bought a 51% stake in the new SUN Microsystems company, which then made only high-end UNIX workstations. AT&T and SUN announced that starting with UNIX SVR4, the operating system would be released first only on AT&T and SUN products, and all other UNIX licensees would have to wait 6 months. Outraged by their academic-minded supplier (Bell Labs) now turned competitor (AT&T-CS), the Gang of Seven founded the Open Software Foundation (OSF), each contributing source code from their UNIX SVR3 versions. By the late 1980's, AT&T gave up, sold most of its stake in SUN, spun the UNIX Operating System off as UNIX Systems Laboratories (which was later bought by Novell, then SCO), canceled its WE 32000 (aka BELLMAC) and CRISP microprocessor product lines, and concentrated on networked server computer systems.

AT&T-CS produced many "firsts" in the computer world, besides the UNIX Operating System itself. The 3B5 (1981) and 3B15 (1982) were the first servers to be designed with the 32-bit WE 32000 microprocessor, and the 3B15 was the first computer to run a demand-paging version of UNIX. The 3B2 was the first desktop supermicrocomputer (1983) with a 32-bit microprocessor and UNIX, and the various versions of it were the first to introduce asymmetric multiprocessing (3B2/600 Falcon) and later, a nearly-symmetrical multiprocessing version (3B2/1000 Galactica). The Falcon won the highly-touted US Air Force Office Automation contract, initially estimated at $1.7 billion, and the largest single computer contract the Federal government had awarded at that time.

The "Companion" laptop was developed, the first to have a 32-bit CPU and UNIX. The "Alexander" system measured about 12 inches on each side square, and 5 inches high, featured a unique opto-coupling stacking I/O bus for up to 8 cards, featured compressed UNIX filesystems on pluggable ROM cartridges like modern gaming consoles, and used the WE 32100 running UNIX SVR3. On the large side, the 3B4000 was the first "snugly-coupled" multiprocessor, containing the ABUS (supporting 16 large single-board computer circuit panels), and featuring the first UNIX SVR4 distributed UNIX kernel (codenamed Apache, nothing to do with the open source project started in the 1990s). The StarServer E ("Enterprise" or SSE) was an Intel-based symmetric multiprocessor (SMP), introduced just after the Sequent system, making the SSE the world's second UNIX symmetric multiprocessor (SMP), and the first to run UNIX SVR4. AT&T-CS also introduced the world's first PC&C (personal computer and communication), the famous AT&T Safari laptop, the first to have built-in modem and networking.

AT&T also bought OEM systems from Tandem Computers and Pyramid Computers. The Tandem Integrity S2 was renamed the StarServer FT and sold only internally to other AT&T divisions. The Pyramid Computer System System 7000 was a large symmetric multiprocessor (SMP), and saw its first large-scale application at AT&T Universal Cards credit-card billing center, the first enterprise-scale replacement of mainframes by a UNIX server within AT&T. Both these systems used the MIPS R-series RISC microprocessors. After the WE 32000 microprocessors were canceled, the 3B2 follow-on (codenamed Phoenix) was also to use a MIPS CPU. The entire MIPS-based product line was renamed the System 9000, and featured "scalavailbility" - from normal commercial availability (NCA) choices, to fault-tolerant, to high performance SMP.

The System 9000 strategy was canceled when AT&T's Board of Directors decided to close down AT&T Computer Systems, and buy the NCR Corporation, announced in 1991, and implememnted January 1, 1992. NCR management tried to cancel all further development of AT&T-CS systems, though some refused to die for a few years. NCR had just developed and suddenly canceled it Motorola 88000-based systems, and then started the NCR 3000 series, developed using Intel microprocessors. The AT&T StarServer E could still beat the comparably equipped NCR 3450 by 11% in the TPC Benchmark B test, and the SSE's 7 patented innovations were then adapted and retrofitted into the NCR 3000 design. NCR was renamed AT&T Global Information Solutions in 1994. The Naperville IL operation provided LifeKeeper Fault Resilient System software (a failover software cluster product), the Distributed Lock Manager for Oracle Parallel Server, and the Vistium computer-telephony integrated on-line hardware-assisted networked meeting product. Only about 400 employees remained in the Naperville location by the beginning of 1995. In the mid-1980s, there had been something like 30,000 employess associated with AT&T-CS, including marketing, customer support, factories, and development (someboady correct that figure if wrong, please).

On September 20, 1995, Bob Allen, AT&T Chairman of the Board and CEO, announced the "trivestiture" - the 3-way split of AT&T into the new service-oriented AT&T. a newly independent NCR, and the new equipment-oriented business which would later be named Lucent Technologies. On December 15, 1995, the former AT&T-CS operations were shut down, signaling the end of AT&T's involvement in designing computer systems.