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

Scientific Time Sharing Corporation (STSC) was formed in 1969 inBethesda, Maryland by Dan Dyer,Burton C. Gray, and some of the people who originally implemented the programming languageAPL, notablyPhilip S. Abrams,Lawrence M. Breed, and Allen Rose.^[3] In 1970, STSC releasedAPL*Plus, a version of theAPL\360 language with many practical extensions oriented toward fostering business use of APL. Together withI. P. Sharp Associates, STSC made many enhancements to the APL language, including:

• []FMT formatting
• []VR and []FX, APL programreflection features
• a file system to store APL variables outside of the APL environment

STSC continued to make enhancements to theinterpreter, notably improving the performance of many of the primitivefunctions.

In 1985, Dan Dyer of STSC and Ian Sharp ofI. P. Sharp Associates jointly received theKenneth E.Iverson Award for Outstanding Contribution to APL.

In the early 1980s, the timesharing market began collapsing, mostly due to the appearance in the marketplace of relatively lower cost IBMmainframe computers, such as theIBM 4300. STSC quickly changed its focus to supply APL services for in-house and the rapidly developingpersonal computer (PC) market.

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

In the mid 1980s, STSC released an APLcompiler for its APL*Plus add-on for the IBM VSAPLprogram 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.

By the mid 1990s, theAPL*Plus/386 system had become one of the leading APL interpreters in the market, however it did not run under the then-newMicrosoft Windows 3.1. Although there were some attempts at Windows interoperability, development on theAPL*Plus/Win product began shortly before the APL products were sold toLEX2000. This latest Windows product is the basis for the currentAPLNow (formerlyAPL2000) interpreter product line.

• 1969 – Scientific Time Sharing Corporation formed
• 1971 – APL Mailbox, also called 666 BOX, an early email system byLarry Breed and Francis Bates^{[4][5][6]: 34}
• 1976 – STSC Mailbox used to coordinate theJimmy Carter presidential campaign^[6][7][8]
• 1979 – the firm name was changed toSTSC, Inc.
• 1982 – APL*Plus/PC launched, one of the first versions of APL on thepersonal computer
• 1982 – acquired by Continental Telecom, Inc.
• 1990 – acquired Rover Technology Co.^[9]
• 1992 – name changed to Manugistics Group, Inc.
• 1993 –initial public offering
• 1995 – the APL product line was sold toLEX2000, Inc.
• 1999 –Cognos Corporation acquired LEX2000

Manugistics continued to own all supply chain software.

• Kenneth Iverson

• APL programming language - Chronology
• Catherine Lathwell, ed. (c. 1979)."The STSC Story: It's About Time". Scientific Time Sharing Corporation.Archived from the original on 2021-12-19. Retrieved2017-01-06. Promotional video for Scientific Time Sharing Corporation, which features PresidentJimmy Carter's press secretaryJody Powell explaining how the company'sAPL Mailbox enabled the 1976 Carter presidential campaign to easily move information around the country to coordinate the campaign. Plus many employees and corporate customers explaining how STSC's APL helped them solve business problems.

• Defunct companies based in Maryland
• APL programming language family
• Time-sharing companies