Source : Free On-Line Dictionary of Computing

Task Control Block
     
         An {MVS} {control block} used to communicate
        information about {tasks} within an {address space} that are
        connected to an {MVS} subsystem such as {MQSeries} for
        {MVS/ESA} or {CICS}.
     
        {FAQ
       
     (http://www-4.ibm.com/software/ts/mqseries/library/manuals/csqfao/CSQFAO22.HTM)}.
     
        (2000-12-30)