(Always called "Id") A non-strict, single assignment language and incremental compiler developed by Arvind and Gostelow and used on MIT's Tagged-Token Dataflow Architecture and planned to be used on Motorola's Monsoon.

See also Id Nouveau.

["An Asynchronous Programming Language for a Large Multiprocessor Machine", Arvind et al, TR114a, Dept ISC, UC Irvine, Dec 1978].

["The U-Interpreter", Arvind et al, Computer 15(2):42-50, 1982].