COMMON /CIOSYS/ FDTAB(MAXFILES),FBKTAB(FBLEN,MAXFILES)
   INTEGER FDTAB%# POINTERS TO FILE BLOCKS
   INTEGER FBKTAB%# FILE BLOCKS
   INTEGER FILTAB(1)%# FOR SINGLE-DIMENSION ACCESS TO FBKTAB
   EQUIVALENCE (FBKTAB(1), FILTAB(1))
