Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (F)
Guardian Procedure Calls Reference Manual—522629-013
5-115
FILE_OPEN_ Procedure
sync-or-receive-depth input
INT:value
The purpose of this parameter depends on the type of device being opened:
disk file specifies the number of nonretryable (that is, write) requests
whose completion the file system must remember. A value of 1
or greater must be specified to recover from a path failure
occurring during a write operation. This value also implies the
number of write operations that the primary process in a
process pair can perform to this file without intervening
checkpoints to its backup process. For disk files, this
parameter is called sync depth. The maximum value is 15.
If omitted, or if 0 is specified, internal checkpointing does not
occur. Disk path failures are not automatically retried by the
file system.
$RECEIVE file specifies the maximum number of incoming messages read by
READUPDATE[X] that the application process is allowed to
queue before corresponding reply operations must be
performed.
If omitted or 0, READUPDATE[X] and reply operations to
$RECEIVE are not permitted.
For $RECEIVE, this parameter is called receive depth, and the
maximum number of queued incoming messages is 4047.
process pair specifies whether or not an I/O operation is automatically
redirected to the backup process if the primary process or its
processor module fails. For processes, this parameter is called
sync depth. The maximum value is determined by the process.
The value must be at least 1 for an I/O operation to a remote
process pair to recover from a network failure.
If this parameter >= 1, the server is expected to save or be
able to regenerate that number of replies.
If this parameter = 0, and if an I/O operation cannot be
performed to the primary process of a process pair, an error
indication is returned to the originator of the message. On a
subsequent I/O operation, the file system redirects the request
to the backup process.
For other device types, the meaning of this parameter depends on whether the
sync-ID mechanism is supported by the device being opened. If the device does
not support the sync-ID mechanism, 0 is used regardless of what you specify (this
is the most common case). If the device supports the sync-ID mechanism,
specifying a nonzero value causes the results of that number of operations to be
saved; in case of path failures, the operations are retried automatically.
The actual value being used can be obtained by a call to FILE_GETINFOLIST_.