SNAP-IX TN3270 Administrator's Guide - 2.4 Using Shared Memory and Semaphores

2.4 Using Shared Memory and Semaphores

This section describes how to define the amount of shared memory and semaphores required by SNAP-IX TN3270 on the Solaris computer.

Normally, the default values for these parameters are suitable for typical SNAP-IX TN3270 configurations. In some cases, it may be necessary to tune some of these parameters. Tuning should only be done once SNAP-IX TN3270 has been successfully installed and started using the defaults. The parameters should be set to large enough values to accommodate both the SNAP-IX TN3270 requirements and the requirements of any other programs on the system.

If you need to change any of these values, refer to your Solaris documentation for information about how to set them.

Following are the tuning parameters and their recommended values:

shminfo_shmmni: 1 + (number of concurrent copies of the TN3270 emulation program) + (total number of sessions configured for HLLAPI)
seminfo_semmni: (2 × number of concurrent copies of the TN3270 emulation program) + (total number of sessions configured for HLLAPI)
seminfo_semmns: (2 × number of concurrent copies of the TN3270 emulation program) + (2 × total number of sessions configured for HLLAPI)
seminfo_semmap: Half the value of shminfo_semmns
seminfo_semmnu: (2 × number of concurrent copies of the TN3270 emulation program) + (total number of sessions configured for HLLAPI)
shminfo_shmseg: 2 + (maximum number of sessions configured for HLLAPI for a single user)

Note

A user can run more than one TN3270 emulation program at a time, using different HLLAPI session identifiers, and so can have more HLLAPI sessions configured than a single emulation program can support. These parameters must be large enough to support all these sessions, even if the user does not access all of them from a single HLLAPI application.