DTHEADER DSECT                                                                  
DTHPOSF  DS    F                         Data Table First Entry Num             
DTHPOSL  DS    F                         Data Table Last Entry Num              
DTHNEXT  DS    F                         Next Data Table Address                
DTHPREV  DS    F                         Previous Data Table Address            
DTHL     EQU   *-DTHEADER                Length                                 
