History Timeline

1964   Digital Equipment Corporation introduced the PDP-6 computer, a 36-bit system intended primarily for scientific computing. Its features were greatly influenced by Dr. John McCarthy, the creator of the LISP programming language and inventor of the concept of timesharing in computers, who was at MIT when the design began. (One of the first PDP-6 systems was purchased by the Stanford Artificial Intelligence Laboratory, headed by Dr. McCarthy.)

The PDP-6 was a commercial failure. Only 23 were produced and sold. However, the system architecture was popular enough that a new version, designated the PDP-10, was begun in 1965.

The MIT Artificial Intelligence Laboratory programmers created a new operating system for the PDP-6, which they called the Incompatible Timesharing System.
 
1967   The first PDP-10 system was introduced. Twice as fast as the PDP-6, it was the basis for a number of very successful research and commercial offerings. DEC continued to develop the operating system, based on the original PDP-6, adding features until, with version 5, they renamed it Tops-10.

Variants of Tops-10 sprang up in a number of places: The Stanford AI Lab produced WAITS, the timesharing service bureau Tymshare created TYMCOM X, Compuserve—the list goes on and on. The MIT AI Lab ported ITS to the new machine. And some people used the PDP-10 as a research vehicle into the basis of computing itself: Bolt, Beranek, & Newman (the think tank that was the home of the ARPANET) added a pager and created a virtual memory operating system called TENEX.
 
1970   The Lakeside School began teaching its students the fundamentals of programming, with computing services provided on a PDP-10. Paul Allen first learned BASIC.
 
1971   DEC brought out the next model of the PDP-10, the KI-10, much larger and faster than its predecessor. The system is renamed the DECsystem-10.
 
1975   DEC brought out the most successful model of the PDP-10, the KL-10. This system is microcoded, allowing for architectural improvements without the creation of entirely new hardware.

In addition to Tops-10, they offer a new operating system, Tops-20, based on TENEX from BB&N but with a number of new features. When running this new operating system, the system is called the DECSYSTEM-20.

This version of the PDP-10 is used over the next decade and a half by Microsoft to develop versions of BASIC for the various microcomputer systems that appeared on the market at this time, starting with the original Altair 8800 in 1975.
 
1978   DEC introduced a smaller version of the PDP-10, the DECSYSTEM-2020 or KS-10, which was designed to use the peripherals created for the PDP-11 family of minicomputers in order to lower the cost of ownership.
 
1983   DEC announced the cancellation of the long-awaited next generation of the PDP-10 family, codenamed "Jupiter," and with it the end of the entire product line. At the request of the large customer base, they commit to a further five years of hardware development and support, to make the peripherals designed for Jupiter available on the older hardware, and to ten years of software development and support.
 
1986   Systems Concepts, a manufacturer of peripheral interfaces for the PDP-10, introduced the SC-30M, first of a family of PDP-10 clones. This was architecturally a duplicate of the KL-10 processor from DEC, allowing customer to use their old peripherals.

The first customer delivery is to the academic computing facility at Stanford. Their largest customer, Compuserve, eventually licenses the design and builds their own to meet their needs.
 
1995   XKL introduced the Toad-1 System, a PDP-10 follow-on which implemented the full memory architecture first envisioned by DEC for the KL-10 in 1975 and used modern peripherals instead of retrofitting DEC gear.
 
1997   Paul Allen purchased a Toad-1 as part of his growing collection of historically important computers.
 
2003   Efforts began to return the KL-10 systems in Paul Allen's collection to working condition. Nearly two years pass before the first system is ready to be put on the Internet for public access.