Incompatible Time Sharing System

The Incompatible Time Sharing System (ITS) was developed at the MassachusettsInstituteOfTechnology's AI Lab (http://ai.mit.edu/) in the late 1960s. It was written in AssemblyLanguage and ran on DigitalEquipmentCorporation's PDP-10s at MIT until 1990, and then until 1995 at the Stacken Computer Club in Sweden.

Despite its small user base, it has had immense influence due to the software originally developed for it. This includes:

• EmacsEditor
• Info (the very first WikiForum, now ported onto Unix)
• TecoEditor
• MacLisp (the precursor of EmacsLisp and CommonLisp)
• MacSyma (a symbolic mathematics system, precursor of MaximaPackage)
• SchemeLanguage also

The JargonFile also started out life on ITS.

ITS nowadays runs on KenHarrenstien?'s PDP-10 simulator (http://klh10.trailing-edge.com/). A snapshot of the final file system (except for user pages) can be found at (http://www.its.os.org/). The modern JargonFile entry is http://catb.org/~esr/jargon/html/I/ITS.html.

Processes were structured hierarchically in ITS. Files were grouped into directories, one per user. It was possible to access files on other machines over the network.

-- And no more than six characters per filename. SchemeLanguage was originally called SCHEMER, a play on CarlHewitt's PLANNER, but the name was truncated to SCHEME to fit on ITS. (http://www.informatik.uni-bremen.de/~net/history.html) GuySteele himself tells the story at 9:08 of http://video.google.com/videoplay?docid=-4633168320660258097&hl=en .

For further information, see http://web.onetel.com/~hibou/ITS.html.

-- DonaldFisk

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CategoryOperatingSystem