Texas Instruments 990 User Manual page 100

Applications Programming
12. Program B executes a call to write/send data to program
A with an I/O opcode 2.
13. Program B begins routine processing.
14. When the data addressed to program A
primary station, activation services
program from the time delay.
arrives at
activates
the
the
15. Program A executes a call to read the input data
addressed", to it with an I/O opcode 3.
16. Program A processes the da ta received and verifies that
program B received all the data addressed to it.
If program A had executed the read call in step 15 and found no
input data addressed to it, program A would know that, the time
delay had expired. It would then execute a call to activation
services with an I/O opcode 7 in order to remove itself from the
activation services list. The program might then return to step
2 to attempt to communicate with program B a second time, or it
might take some alternate action.
If after step 16, program A anticipated other, unscheduled
communications with program B, it would execute a call to
activation services to activate it from termination (that is, it
would request to be bid). The program would then request the
operating system to terminate it. (Program A must be installed
in the program file named INDSCOMM.USERPROG and assigned to
global LUNO >40.) When input data addressed to program A arrives
at the primary station, activation services bids program A for
further processing.
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