V1/man/man4/rfo.4

        11/3/71                                                /DEV/RFO (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 devices (tape, RK
                  disk) this file is addressed in blocks, not bytes. This
                  has two consequences: seek calls refer to block numbers,
                  not byte numbers; 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 characters from successive
                  blocks.

FILES

SEE ALSO          /dev/tap0, /dev/rk0

DIAGNOSTICS

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