Some processes require buffers to be fixed into real storage. An application can specify fixed buffers (BUFTYPE=FIXED parameter) on the GET_BUFFER and ASSIGN_BUFFER requests. Availability of fixed buffers is limited by the system definitions in the installation's CSM parmlib member. The application can obtain pageable buffers when fixed buffers are unavailable and use the FIX_BUFFER request to make the buffers fixed at a later time.