- Unix-Based System Settings

The PROIV filing system PROISAM uses system semaphores to manage concurrent access to files. The Unix system configuration values for semaphore usage may need to be changed since they may restrict the number of concurrent users of PROIV. This is particularly likely on larger Unix systems.

Unfortunately, the configuration parameters vary from system to system, as may the configuration utility (it is usually /usr/sys/conf). The semaphores must be set up to allow as many users to wait on a semaphore, as there are to be PROIV users. As many users to be notified by a semaphore as there are to be PROIV users and as, many users of a semaphore as there are to be PROIV users.

If there are problems with the system configuration, one of the following error messages will appear, and you should contact your system administrator:

Message	Reason
SD_ENTER:	No space left on device, or another user has removed the shared memory segment you are using
SD_WAIT:	No space left on device
SD_ENTER:	Result too large
SD_WAIT:	Result too large, or
	Opened file twice, or
	Closed unopened file, or
	Requested currency for file not in list, or
	Error putting currency, or
	Locking record against unopened file, or
	Error Unlocking Record, or
	File catalog corrupt (Causes an abort and memory dump), or
	Record catalog corrupt (Causes an abort and memory dump)

Possible System Messages when out of Semaphores

The PROIV Virtual Machine, in combination with the filing systems it interfaces with, is dependent on Unix system resources that are configured via Unix kernel parameters. To increase these resources (for example, the number of open files allowed per user) you may reconfigure the parameters and rebuild a modified Unix kernel.

The utilities to support this process, and the naming of the specific parameters, may differ between different Unix environments. However, it is useful to outline those specific Unix parameters upon which PROIV is heavily dependent.

Kernel Parameter	Description
NFILE	The maximum number of files that can be open simultaneously
SEMMNU	The numbers of semaphore undo structures. Allow at least one per user process.
FLCKREC	The maximum number of record locks. Generally, allow at least 20 locks per user. Note that the C-ISAM filing system will use one lock per user per index file open, irrespective of whether the index is locked.

Unix Kernel Parameters

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Topic ID: 720267