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

NAME
     RM - RM02, RM03 moving-head disk

DESCRIPTION
     Files with minor device numbers 0 through 7 refer to various
     portions of drive 0; minor devices 8 through 15 refer to
     drive 1, etc.  The standard device names begin with ``rm''
     followed by the drive number and then a letter a-h for par-
     titions 0-7 respectively.  The character ? stands here for a
     drive number in the range 0-7.

     The origin and size of the partitions (in 512-byte sectors)
     on each drive are as follows:

     Partitions:
          disk      start     length    cyls      function on drive 0
          rm?a      0         4800      0-29      /
          rm?b      4800      4800      30-59     swap
          rm?c      9600      122080    60-822    /usr
          rm?d      9600      62720     60-451    alternate
          rm?e      72320     59360     452-822   alternate
          rm?h      0         131680    0-822     whole pack

     Special files should only be created for the partitions that
     are actually used, as the overlap in these addresses could
     lead to confusion otherwise.

     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 names 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 calls should specify a multiple of
     512 bytes.

FILES
     /dev/rm[0-7][a-h]   block files
     /dev/rrm[0-7][a-h]  raw files

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

DIAGNOSTICS
     rm%d%c: hard error bn %d cs2=%b er1=%b.  An unrecoverable
     error occured during transfer of the specified sector of the

Printed 7/31/83                                                 1

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

     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 (including offset positioning
     and drive recalibration) could not recover the error.

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

     rm%d%c: soft ecc bn %d.  A recoverable ECC error occurred on
     the specified sector of the specified disk partition.  This
     happens normally a few times a week.  If it happens more
     frequently than this the sectors where the errors are occur-
     ing should be checked to see if certain cylinders on the
     pack, spots on the carriage of the drive or heads are indi-
     cated.

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.

     DEC-standard error logging should be supported.

     A program to analyze the logged error information (even in
     its present reduced form) is needed.

     The partition tables for the file systems should be read off
     of each pack, as they are never quite what any single
     installation would prefer, and this would make packs more
     portable.

Printed 7/31/83                                                 2