 Pointers are represented in 16 bytes, containing the target address and a description of the referenced item, thus permitting "bad" pointer use to be diagnosed.In a conversational environment when an error is detected, control is passed to the user who can inspect any variables, introduce debugging statements and edit the source program.Over time the debugging capability of mainframe programming environments developed most of the functions offered by this compiler and it was withdrawn (in the 1990s?)