Ports-A Method for Dynamic Interprogram Communication and Job Control
RAND CORP SANTA MONICA CA
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The report describes Ports, a unified method for communication between a computer program and terminals, files, peripheral devices, other programs, and supervisory software. In ISPL each job has a Port named MONITOR that handles resource allocation creating and deleting files, assigning file space, core space, processor time. This design permits a hierarchical system of monitors, each controlling the jobs running under it. By routing output to a user terminal, Ports enable on-line debugging and simulation of rewritten files of programs. The Port concept improves modularity in 3 ways Each connection need not be specified by the programmer but can be decided at execution Linkage between programs is co-routine rather than subroutine, which simplifies programming, retains context, and removes the need for hierarchical organization With different connections via Ports, the same system can be used in many ways, e.g., on-line or off, in simulation mode, audit-trailed, or data breakpointed.
- Computer Programming and Software