John and Martin. An interpreted FORTH-like graphics language by John Warnock and Martin Newell, Xerox PARC, 1978. JaM was the forerunner of both Interpress and PostScript. It is mentioned in PostScript Language reference Manual, Adobe Systems, A-W 1985.
A condition on a network where two nodes transmitting simultaneously detect the collision and continue to transmit for a certain time (4 to 6 bytes on Ethernet) to ensure that the collision has been detected by all nodes involved.