Digital Equipment Corporation: Encyclopedia II - Digital Equipment Corporation - History

Digital Equipment Corporation - History

The company was founded in 1957 by Ken Olsen and Harlan Anderson, two engineers who had been working at MIT Lincoln Laboratory on the TX-2 project. The TX-2 was a transistor-based computer using the then-huge amount of 64K 36-bit words of core memory. When that project ran into difficulties, Olsen left to form DEC with Harlan Anderson, a colleague from his MIT days. At the time the market was hostile to computer companies, and investors shied from their plans. Instead they started building small digital "modules" (each effectively a single component from the TX-2 design) that could be combined together to be used in a lab setting. In 1961 the company was making a profit, and started construction of their first computer, the PDP-1 (PDP being an acronym for Programmable Data Processor).

The first modules were the free-standing "laboratory modules", placing one or two gates inside an extruded aluminum housing. These modules could be stacked up in a pre-configured 19" rack shelf that supplied power to the modules; the logic circuits were then established using banana plug patch cords installed at the front of the modules. The same circuits were then packaged as the first "R" (red) series "Flip Chip" modules. Later, other module series provided additional speed, much higher logic density, and industrial I/O capabilities. Digital published extensive data about the modules in free catalogs that became very popular.

Digital Equipment Corporation - 8-bit computers

The VT180 (codenamed "Robin") was a VT100 terminal with a Z80-based microcomputer running CP/M. This evolved into the Rainbow-100, which had both Z80 and 8088 CPUs and was capable of running CP/M, CP/M-86, and PC-DOS.

Digital Equipment Corporation - 12-bit Computers

To serve laboratories at a lower cost, DEC provided the PDP-5, an early minicomputer in 1963. True success followed with the introduction of the famous PDP-8 in 1964. It was a smaller, 12-bit word machine that sold for about $16,000. The PDP-8 was small enough to fit on a cart. It was simple enough to be used for many roles, and they soon started being sold in huge numbers to new market niches, labs, railways, and all sorts of industrial applications.

The PDP-8 was important historically because it was the first computer that was regularly purchased by a handful of end users as an alternative to using a larger system in a data center. Because of their low cost and portability, these machines could be purchased to fill a specific need, unlike the mainframe systems of the day that were nearly always shared among diverse users. Today the PDP-8 is generally regarded as the first minicomputer. The PDP-8 spawned a cousin, the PDP-12, which merged data acquisition and display capabilities developed with the NIH-sponsored LINC computers into the PDP-8 architecture.

Digital Equipment Corporation - 16-bit computers

Another of the famous machines in the PDP series was the PDP-11, which, following an industry trend for 8-bit bytes, used a 16-bit word. PDP-11 machines started in the market essentially as upscale PDP-8s, but as improvements to integrated circuits continued, they eventually were packaged in cases no larger than a modern PC.

The PDP-11 systems supported several operating systems of the day, including Bell Labs' new UNIX operating system as well as DEC's RSX and RSTS. Both RSTS and UNIX were available to educational institutions at little or no cost, and these PDP-11 systems were destined to be the sandbox for a generation of engineers and computer scientists.

The PDP-11's 16-bit, byte-oriented architecture provided a 64KB virtual address space. Most models had a paged physical memory architecture and memory protection features to allow timesharing, and some could support split Instruction & Data spaces for an effective virtual address size of 128KB and a physical address size of up to 4MB.

Digital Equipment Corporation - 18-bit Computers

Through the 1960s DEC produced a series of machines aimed at a price/performance point below IBM's mainframe machines, typically based on an 18-bit word, using core memory: the PDP-1, the PDP-2 (proposed, but never built), the PDP-4 (1963), the PDP-7 and PDP-9 (1965), and finally the PDP-15 series (starting in 1970 and later sold as the "XVM" series). The PDP-15 was an early user of TTL integrated circuits. These computers were moderately powerful computers for their time, mainly used in industrial, scientific, and medical laboratories.

Digital Equipment Corporation - 36-bit computers

For larger scientific problems DEC produced first the PDP-6 in 1964, using a 36-bit architecture. Using the same word length of the IBM 701-7094 series, which was being replaced by the 32-bit IBM 360 series, provided an alternative growth path for scientific customers. The successor was the PDP-10 series, eventually being sold as the DECsystem-10 and DECSYSTEM-20

Digital Equipment Corporation - VAX Computer series

In 1976 DEC decided to move to an entirely new 32-bit platform, which they referred to as the super-mini. They released this as the VAX (Virtual Address eXtension) 11/780 in 1978, and immediately took over the vast majority of the minicomputer market. Desperate attempts by competitors such as Data General (which had been formed in 1968 by a former DEC engineer who had worked on a 16-bit design that DEC had rejected) to win back market share failed, due not only to DEC's successes, but the emergence of the microcomputer and workstation into the lower-end of the minicomputer market. In 1983, DEC cancelled their "Jupiter" project, which had been intended to build a successor to the PDP-10, and instead focused on promoting the VAX as their flagship model.

The VAX series had an instruction set that is rich even by today's standards (as well as an abundance of addressing modes). In addition to the paging and memory protection features of the PDP series, the VAX supported virtual memory. The VAX could use both Unix and DEC's own VMS operating system.

At its peak in the late 1980s, Digital was the second-largest computer company in the world, with over 100,000 employees. It was during this time that they appeared to gain a feeling of invincibility, and branched out into software, producing products for almost every then "hot" niche. This included their own networking system, DECnet, file and print sharing, relational database, and even transaction processing. Although many of these products were well designed, most of them were DEC-only or DEC-centric, and customers frequently ignored them and used 3rd party products instead. This problem was further magnified by Olsen's aversion to advertising and his belief that well-engineered products would sell themselves. Hundreds of millions of dollars were spent on these projects, at the same time that workstations based on RISC architecture were starting to approach the VAX in performance. Blinded by their own success of the VAX/VMS products which followed the proprietary model, the company executives would later be blind-sided by commodity hardware in the form of Intel-based personal computers and standards-based software such as Unix and Internet protocols such as TCP/IP. In the early 1990s DEC found its sales faltering, and its first layoffs followed.

In 1990 DEC was about to launch a new generation of computer disk drives into the marketplace. Code named the RA90, it was the second largest development project ever undertaken by the company. Several major technological innovations were to be simultaneously integrated into this state of the art (at the time) product. Unfortunately, because of product design glitches, the RA90 was very late in coming to market. By the time enough glitches had been resolved to allow limited shipments, competitors had released enhanced technology drives at much lower prices. What could have been a huge win for this organization became a great failure.

Digital Equipment Corporation - Alpha

During the 1980s DEC made several attempts at designing a RISC processor to replace the VAX architecture. Eventually, in 1992 DEC launched the Alpha processor (initially named Alpha AXP, the "AXP" was later dropped). This was a 64-bit RISC architecture (as opposed to the 32-bit CISC architecture used in the VAX) and one of the first 64-bit microprocessor designs. The Alpha offered class-leading performance at its launch, and subsequent variants continued to do so into the 2000s. Alpha-based computers (the DEC AXP series, later the AlphaStation and AlphaServer series) superseded both the VAX architecture and the MIPS-based DECstation line, and could run VMS, Unix and Microsoft's new server operating system Windows NT.

DEC tried to compete in the Unix market by marketing the VMS operating system as "OpenVMS" and by selling their own Unix (OSF/1 AXP, later renamed Digital UNIX), and it began to advertise more aggressively. DEC was simply not prepared to sell into a crowded Unix market however, and furthermore the low end PC-servers running NT (based on Intel processors) took marketshare from Alpha-based computers. DEC's workstation and server line never gained much popularity beyond former DEC customers.

Digital Equipment Corporation - Closing DEC's Business

Ken Olsen was replaced by Robert Palmer as the company's CEO, but Palmer was unable to stem the tide of red ink and more rounds of layoffs ensued. DEC's database product was sold to Oracle, and its high-end Storageworks disk unit sold to Quantum Corporation. In May 1997 DEC sued Intel for allegedly infringing on its Alpha patents in designing the Pentium chips. A settlement reached in DEC's favour included sale of DEC's chip business to Intel. In 1997, the printer business was sold to GENICOM who produced models with the Digital logo. About the same time its networking business was sold to Cabletron Systems, and eventually the company itself was sold to Compaq on January 26, 1998. Compaq itself was taken over by Hewlett-Packard in 2002.

The Digital logo survived for a while after the company ceased to exist, as the logo of Digital GlobalSoft, an IT services company in India (which was a 51% subsidiary of DEC). Digital GlobalSoft was later renamed "HP GlobalSoft", and no longer uses the Digital logo nor follows the erstwhile Digital culture of engineering predominance.

Adapted from the Wikipedia article "History", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki