! I/O related record formats added
%end %of %list
! File descriptor for directory service
%record %format  fdfm (    %c
   %byte unit, fsys,
   %byte %array fname(1:6) %c
)
! Internal stream descriptor
%record %format  sdfm ( %c
   %integer  type,      { =char/file type etc. }
  (%record(fdfm)  file %or { descr. for Dir.fn.   }
   %string(7) device),
  (%integer  block %or  { current block number }
   %integer  len),      { length of output line}
   %integer  buffad,
             buffp,     { address of next char }
             ebp,       { 1 beyond last char   }
   %byte     ser,       { of handler process.  }
             sym,       { this char            }
   %integer  state,     { of stream            }
             refs       { for buffer management} %c
)
! Combined descriptor/buffer format - for file streams
%record %format  sbfm (  %c
   %record(sdfm) sd,
   %bytearray bf (0:511) %c
)

%const %record(sdfm) %name  null == 0

%list
%end %of %file