11/3/71                                             /DEV/RF0 (IV)

NAME            rf0  --  RF11-RS11 fixed-head disk file

SYNOPSIS        --

DESCRIPTION     This file refers to the entire RF disk.  It may

                be either read or written, although writing is

                inherently very dangerous, since a file system

                resides there.

                The disk contains 1024 256-word blocks, numbered

                0 to 1023.  Like the other block-structured de-

                vices (tape, RK disk) this file is addressed in

                blocks, not bytes.  This has two consequences:

                seek calls refer to block numbers, not byte num-

                bers; and sequential reading or writing always

                advance the read or write pointer by at least one

                block.  Thus successive reads of 10 characters

                from this file actually read the first 10 charac-

                ters from successive blocks.

FILES           --

SEE ALSO        /dev/tap0, /dev/rk0


BUGS            The fact that this device is addressed in terms

                of blocks, not bytes, is extremely unfortunate.

                It is due entirely to the fact that read and

                write pointers (and consequently the arguments to

                seek and tell) are single-precision numbers.

                This really has to be changed but unfortunately

                the repercussions are serious.

OWNER           ken, dmr