The system assigns an ASID to an address space when the address space is created. A limited number of ASIDs are available for the system to assign. When all ASIDs are assigned to existing address spaces, the system is unable to start a new address space. This condition might be the result of too many lost ASIDs in the system. A lost ASID is one that is associated with an address space that has terminated, but because of the address space's cross memory connections, the system does not reuse the ASID. In effect, the ASID is "lost from use" for the duration of the IPL, or until all connected address spaces have terminated.

This section tells you two ways to reduce the possibility that the system will run out of ASIDs for assignment to new address spaces. One is through coding cross memory services to avoid losing ASIDs and the second is through the installation's use of parameters in the IEASYSxx member of SYS1.PARMLIB.