The activation of a process or activity either in a separate unit of work from the requestor or with the transaction attributes specified on the DEFINE PROCESS or DEFINE ACTIVITY command, rather than with those of the requesting transaction. The relationship of the process or activity to the requestor is as between separate transactions, except that data can be passed between the two units of work.A context switch occurs when a process or activity is activated by a RUN command, but not when it is activated by a LINK command.