OSI/TS Configuration and Management Manual

NonStop Kernel File-System Interface
OSI/TS Configuration and Management Manual—424831-001
7-11
Setting and Retrieving Subdevice Parameters
) procedure performs this task. In the OPEN call, you specify the name of the
OSI/TS subdevice and, in the flag word, several important parameters:
Your application can open multiple subdevices, and multiple applications can use
the same subdevice, if the subdevices are opened with shared access. You can
associate applications with subdevices any way you choose. However, if multiple
processes open the same subdevice, then either certain tasks should be undertaken
by only one of the processes, or the tasks should be carefully coordinated among
them all. Here are some suggestions:
•
Only one process should set or change subdevice parameters.
•
Only one process should request transport connection establishment, and the
same process should request connection release.
•
Only one process should issue the READ call to accept asynchronous
messages from the OSI/TS subsystem.
Setting and Retrieving Subdevice Parameters
After the subdevice is open, you can use the SETPARAM procedure to examine
and change subdevice characteristics. Table 7-3 shows the SETPARAM
operations that apply to OSI/TS subdevices.
Shared or
exclusive access
to the subdevice
If more than one application uses the subdevice or if the
application opens it more than once, you must indicate
shared access.
Read/write
access mode
You must specify this mode.
Wait or nowait
I/O
If you specify wait I/O, an application can issue only one
request at a time to the OSI/TS subsystem. The file
system does not return control to the application until the
request is completed. If you specify nowait I/O, an
application can have multiple requests pending
simultaneously.
Note. If your application specifies nowait I/O in the OPEN call, you should also call
SETMODE 30 to allow requests to multiple subdevices to complete out of sequence.
Table 7-3. SETPARAM Functions
SETPARAM
Operation Function
1 Alter or fetch remote X.25 DTE address.
10 Fetch current status block for subdevice.
11 Set or fetch security parameter to be sent in CR-TPDUs.