This was followed by a 16-bit "minicomputer" as it came to be called, the PDP-11, in the 1970s. PDP-8 and PDP-11 overlapped for about 10 years before the "8" became extinct. The PDP-11 became extraordinarily popular. It had a single user foreground/background operating system – RT-11, a time-sharing one - RSTS, and a multi-user real-time OS called RSX. Among the PDP-11's hardware innovations was the use of a Unibus for CPU-memory and I/O operations instead of having a separate I/O bus.
Competitors joined in a minicomputer boom including Honeywell, Data General, Burroughs, Wang and others. The route 128 ring around Boston became known as a minicomputer area and there were intense rivalries between the vendors. Wang had a large building in Boston and at, one time, a visiting BP executive being transferred by helicopter from Logan airport to the Mill was told W.A.N.G. was a local radio station.
Eventually the PDP-11's addressing limitations of having just 16-bit words became too much and DEC moved on to its most famous and popular minicomputer line, the 32-bit VAX (Virtual Address Extension), a supermini. Along the way DEC devised and built its own disk drive storage products, including 5- and 10MB removable drives, printers and network interface products.
The VAX operating system was VMS and was both a real-time and time-sharing system. DEC also has larger time-sharing machines, PDP-10s, but these did not have VAX-levels of popularity. DEC also developed is own flavour of Unix called Ultrix but it played second fiddle to VMS. The company produced VMS office automation software, All-in-One, which was a suite of software including word processing, mail, and other middleware applications.
Data General, IBM and others also produced 32-bit superminis and DEC's always ambitious goal of replacing mainframe computers quietly faded away as IBM's own superminis, the System 38 which became the AS400, survived and prospered.
Users accessed PDP and VAX systems through terminals, so-called green screens. Although DEC liked giving smaller businesses their own computers it did not like giving individual users their own computers or even see the need to do so. This was a Ken Olsen view and was a mistake. DEC resisted the development of the PC and this was one factor, a huge one, that led to its downfall.
Nowhere, over the Rainbow
Eventually DEC had to produce a PC and did so, the Rainbow, but there was no pot of gold at the end of this disappointing and half-hearted product. It launched with restricted software available, an on-screen clock for example, with imitation analogue hands. This was an appallingly bad product and was rapidly eclipsed by the IBM PC, and then by Compaq.
Compaq's products became ever more popular and DEC's declined. The Santa Cruz Operation and other companies ported Unix to the PC and showed that its hardware was powerful enough to run multi-user software. The PC ecosystem grew and grew, fuelled by Microsoft software and by Unix. PC-style computing thrived
DEC became the second largest computer company in the world and achieved $14bn annual revenues in the late 80s. At its peak it employed more than 120,000 people. However, the PC showed up DEC's shortcomings, particularly Olsen's inability to recognise its potential. He had a paternalistic and somewhat autocratic management style and this hindered DEC's ability to adapt to events. DEC's board forced resignation on him in 1992, and it sold the company to Compaq in 1998 for $9.6bn.
Compaq was in turn was acquired by in 2002 by HP in a tumultuous $25bn takeover with much board-level dissension inside HP.
Olsen's wife died in 2009. He is survived by a daughter and son, five grandchildren and a brother. ®