U UNIVAC 1218 - Bitsavers

50 15
50 16
50 17
TERMINATE INPUT (INSTP)
Execution time: 4 microseconds
Terminate input on channel k.
CLEAR INPUT ACTIVE CHAN. k
No monitor interrupt will occur as a result of
the execution of this instruction.
TERMINATE OUTPUT (OUTSTP)
Execution time: 4 microseconds
Terminate output on channel k.
CLEAR OUTPUT ACTIVE CHAN. k
No monitor interrupt will occur as a result of
the execution of this instruction.
TERMINATE EXTERNAL FUNCTION (EXFSTP)
Execution time: 4 microseconds
CLEAR EXTERNAL FUNCTION ACTIVE CHAN. k
Terminate external function mode on channel k.
No monitor interrupt will occur as a result of
the execution of this instruction.
4. OVERRIDE INSTRUCTIONS
Certain peripheral equipments accept external functions and output data from
the computer pnly if the transfer is forced by the computer. The two override
instructions (50 26 and 50 27) force a transfer by simulating a request signal
(output data request or external function request), placing the information on
the data lines, and setting the acknowledge signal. Upon detecting the acknowledge
signal, the peripheral device accepts the data just as if the peripheral
device had requested it. It should be noted that the execution of an override
instruction forces only one transmission; it does not initiate an automatic
buffer.
For example, to send a 3-word external function buffer to a magnetic tape unit,
the external function override instruction (50 27) must be executed three times,
and the programmer must provide a delay between executions to allow time for
the tape unit to accept the information.
50 26 OUTPUT OVERRIDE (OUTOV)
Execution time: 4.67 microseconds
Wait for the output device to accept the word in the
C register(s). Then simulate an output request on
channel k and transfer the word designated by the
address in the output buffer control register for
that channel. Ignore the ESI mode if active. This
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