CICS Dispatcher list

The suspend list contains tasks that waiting for long wait. I/O wait is not considered to be long and thus task waiting for I/O is queued in the active list instead. Long wait are those that may not have a target deadline like terminal I/O or interval control wait etc. 

Tasks in active list are ordered by priority which is calculated as the sum of transaction, terminal and user priority capped to 255 (stored in a byte). 

TCP (Terminal Control) task which is used to attach new task have priority of 255 and is placed on top of the list. Tasks are queued in the active chain in priority order.  New task are placed behind tasks with same priority (FIFO).