CP6100 I/O Process Programming Manual

Using CP6100: Managing Lines
You use this command to make the line accessible to applications.
If the line is already in START state, this command has no
effect.
STOP or ABORT. These commands abruptly stop all work on the
line. No new requests are accepted; pending requests are
rejected with file system error 66. The state changes are:
START --> STOP
ACTIVATE --> SUSPEND
You use STOP to abort line activity when you suspect a hardware
malfunction and want to diagnose the problem (for instance, by
trying to download the LIU again), when you know the line is
not in use and you want to download a new protocol, or when, for
some other reason, you want all work in progress to be
interrupted. Some error conditions cause CP6100 to stop the line
by itself. The discussion of errors in Appendix A includes some
of these cases. ABORT is just like STOP, except that it works
even if the line is open.
SUSPEND. This command forbids any more OPEN requests. An
application that has opened the line may proceed unaffected.
Pending OPEN requests and any new OPEN requests are rejected with
file system error 61. The state changes are:
ACTIVATE --> SUSPEND
You use this command to prevent further OPENs, either to limit
the traffic on a line or to stop the line gradually, letting
all sessions end instead of interrupting them. (The line
remains in START state until you issue a STOP command.)
ACTIVATE. This command reverses the effect of an earlier
SUSPEND command, so the line can again accept OPEN requests.
The state changes are:
SUSPEND --> ACTIVATE
CONTROL. This command downloads the LIU or nullifies an earlier
download, depending on its operand. The LOAD operand downloads
the LIU. The RESET operand changes the state, so a new download
is required for continued operation. The state changes are:
October 1985
3-11