Configuring message queues on UNIX and Linux

In UNIX and Linux® systems, the Client daemon communicates internally using inter-process communication message queues.

In systems other than AIX®, the default configuration settings for these queues are too small to allow for large client data flows (such as 3270 maps or user COMMAREAs). Some symptoms of this problem are:

• An ECI program gives return code -3 (ECI_ERR_NO_CICS)
• A cicsterm locks when a large map is sent to it
• A large number of concurrent ECI requests significantly degrades performance

Change the configuration settings of the message queues to allow for large client data flows. The way that you do this depends on your operating system.