CD_ADDCHANGEINT
    interrupt entry conditions not documented

CD_GETGEOMETRY
    documented as returning io_Actual -- incorrect

CD_TOCLSN
CD_TOCMSF
    documentation focuses on full TOC read;
        need to modify to include partial TOC read

cd.h
    need to include utility/tagitem.h
    need to include devices/trackdisk.h for struct DriveGeometry
