RF(4)               UNIX Programmer's Manual                RF(4)

NAME
     rf - RF11/RS11 fixed-head disk

DESCRIPTION
     This file refers to the concatenation of all RS-11 disks.

     Each disk contains 1024 512-byte blocks.  The length of the
     combined RF file is 1024x(minor+1) blocks.  That is, minor
     device zero is taken to be 1024 blocks long; minor device
     one is 2048 blocks long, etc.

     The block files access the disk via the system's normal
     buffering mechanism and may be read and written without
     regard to physical disk records.  There is also a `raw'
     interface which provides for direct transmission between the
     disk and the user's read or write buffer.  A single read or
     write call results in exactly one I/O operation and there-
     fore raw I/O is considerably more efficient when many words
     are transmitted.  The name of the raw files conventionally
     begin with an extra `r.'

     In raw I/O counts should be a multiple of 512 bytes (a disk
     sector).  Likewise _l_s_e_e_k(2) calls should specify a multiple
     of 512 bytes.

FILES
     /dev/rf[0-7]        block files
     /dev/rrf[0-7]       raw files

SEE ALSO
     dvhp(4), hk(4), hp(4), hs(4), ml(4), rk(4), rl(4), rm(4),
     rp(4), rx2(4), xp(4)

DIAGNOSTICS
     rf%d: hard error bn %d cs=%b dae=%b.  An unrecoverable error
     occured during transfer of the specified sector of the
     specified disk partition.  The contents of the two error
     registers are also printed in octal and symbolically with
     bits decoded.  The error was either unrecoverable, or a
     large number of retry attempts could not recover the error.

     rf%d: write locked.  The write protect switch was set on the
     drive when a write was attempted.  The write operation is
     not recoverable.

BUGS
     In raw I/O _r_e_a_d and _w_r_i_t_e(2) truncate file offsets to 512-
     byte block boundaries, and _w_r_i_t_e scribbles on the tail of
     incomplete blocks.  Thus, in programs that are likely to
     access raw devices, _r_e_a_d, _w_r_i_t_e and _l_s_e_e_k(2) should always
     deal in 512-byte multiples.

Printed 7/31/83                                                 1

RF(4)               UNIX Programmer's Manual                RF(4)

     DEC-standard error logging should be supported.

Printed 7/31/83                                                 2