Spool is the primary medium for all JES2 data. All input jobs and system output (SYSOUT) are stored on the spool. JES2 gives your installation the capability to offload (transmit) data from the spool to a data set and later reload (receive) from the data set to the spool. The spool offload facility can use either tape or DASD as the offload medium.

Spool offload eases the migration from release to release by lessening the impact of a cold start. The facility provides a release-independent means of moving the data on the spool between releases.

Note that spool transmissions can contain clear text versions of all JOB statements. If they are not properly secured, unauthorized discovery of RACF® userid and passwords could occur.