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

NAME
     rl - RL-11/RL01, RL02 moving-head disk

DESCRIPTION
     _R_l? refers to an entire disk as a single sequentially
     addressed file.  The RL01 drives are each 10240 blocks long
     and the RL02 drives are 20480 blocks long.  The standard
     device names begin with ``rl'' followed by the drive number.

     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.  Like-
     wise _l_s_e_e_k calls should specify a multiple of 512 bytes.

FILES
     /dev/rl[0-3]        block files
     /dev/rrl[0-3]       raw files

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

DIAGNOSTICS
     rl%d: hard error bn %d cs=%b da=%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.

     rl%d: hard error sn%d mp=%b da=%b.  An unrecoverable drive
     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.

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

     rl%d: can't get status.  A ``get status'' command on the
     specified drive failed.  The error is unrecoverable.

Printed 5/17/83                                                 1

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

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.

Printed 5/17/83                                                 2