JES2 can perform the following types of starts: 

GLYPH<SM590000> Cold start 

This start occurs when you specify PARM=COLD when JES2 is started. The JES2 spool is cleared of all contents. This type of start requires that all the members of the MAS are stopped. 

Note:  On the system that is performing the cold start, you must take one of the following actions: 

GLYPH<SM590000> Perform an IPL. 

GLYPH<SM590000> Completely stop JES2 and then restart it and specify that it performs a cold start. 

Given that all work on the system must be stopped before this start is performed, little difference exists between stopping and restarting JES2 to perform the cold start and IPLing that system. 

GLYPH<SM590000> Warm start (single system) 

This start occurs when you specify PARM=WARM  when JES2 is started and the starting JES2 member is joining a MAS with other active members. The JES2 checkpoint is read in and processed. Any work that might be associated with this member from a previous instance is reset (marked as no longer actively being processed). 

GLYPH<SM590000> Quick start (single system) 

This start occurs when you specify PARM=WARM  when JES2 is started. This process is the same as a warm start except that no work is associated with this member from a previous instance. This process occurs if the member: 

– Was shut down cleanly by using a $P JES2  command 

– Is starting after an all-member warm or cold start 

– Had its work reset by using a $E MEMBER  command or through the AUTOEMEM  process 

GLYPH<SM590000> Warm start (MAS-wide) 

This start occurs when you specify PARM=WARM  when JES2 is started and the starting member is the first (only) active member of the MAS. As with all other warm starts, the checkpoint is read in and processed. If any entry in the work queue indicates it is active, it is reset then. In addition, certain operating parameters can be reset only on this type of start. 

GLYPH<SM590000> Hot start 

This start occurs when you specify PARM=WARM  when JES2 is started and a previous instance of the JES2 address space had ABENDed and no intervening IPL occurred. As with all other warm starts, the checkpoint is read in and processed. 

Work in the job queue that is associated with processes that were ended when the JES2 address space was ABENDed are reset. However, work that is associated with active address spaces (running jobs, internal readers, and so on) is not reset. That work continues normal processing. 

Note:  When working with a secondary subsystem, all start options are available and affect only the secondary subsystem without any effect on the primary JES2 subsystem. 

