Scientific Time Sharing Corporation

Scientific Time Sharing Corporation (STSC) was a pioneering timesharing and consulting service company which offered APL from its datacenter in Bethesda, MD to users in the United States and Europe.

Scientific Time Sharing Corporation (STSC) was formed in 1969 in Bethesda, Maryland by Dan Dyer, Burton C. Gray, and some of the people who originally implemented the APL programming language, notably Philip S. Abrams, Lawrence M. Breed and Allen Rose. In 1970, STSC released APL*PLUS, a version of the APL\360 language with many practical extensions oriented toward fostering business usage of APL. Together with I. P. Sharp Associates, STSC made numerous enhancements to the APL language, such as:

STSC continued to make enhancements to the interpreter, notably improving the performance of many of the primitive functions.

Dan Dyer of STSC and Ian Sharp of I. P. Sharp Associates jointly received the Iverson Award for their outstanding contributions to APL in 1985.

The timesharing market started to collapse in the early 1980s, mostly due to the appearance of relatively inexpensive IBM mainframes, such as the IBM 4300, in the marketplace. STSC quickly changed its focus to supply APL services for in-house and the rapidly developing personal computer market.

In 1982, STSC released APL*Plus/PC, which was an extremely successful APL interpreter for the IBM personal computer. In the mid 1980s, STSC developed the APL*PLUS/Unix interpreter, a full 32 bit interpreter which was the basis of further APL development, notably APL*PLUS/386, which was later available for Intel 386 class machines and higher. Arguably, the APL*Plus/386 interpreter fostered the exodus of APL applications from the mainframe to the PC environment, as the hardware and software were finally correctly matched to facilitate a straightforward migration of medium- to large sized applications away from the mainframe.

In the mid 1980s, STSC released an APL Compiler for its APL*Plus add-on for the IBM VSAPL program product. Along with language features designed to profile code execution, this compiler implementation was oriented toward replacing resource-consuming functions in place with compiled ones, leading to overall performance improvements.

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