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

NAME
     ml - RH-11, RH-70/ML-11 solid state disk

DESCRIPTION
     The standard device names begin with ``ml'' followed by the
     drive number.  The character ? stands here for a drive
     number in the range 0-7.  The size of each ML-11 unit
     depends on the number of array modules installed.  There are
     512 512-byte blocks per array module, for a maximum size of
     8192 blocks per unit.  The ML-11 may be used for the swap
     device or perhaps mounted on /tmp.

     The ML-11 has switch-selectable transfer rates of 0.25Mb,
     0.5Mb, 1.0Mb, and 2.0Mb per second.  The following transfer
     rate restrictions apply:

          rate       permissible PDP-11 CPUs
          0.25 Mb    all
          0.5  Mb    all
          1.0  Mb    PDP-11/70 with RH-70 only
          2.0  Mb    none

     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(2) calls should specify a multiple
     of 512 bytes.

FILES
     /dev/ml[0-7]        block files
     /dev/rml[0-7]       raw files

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

DIAGNOSTICS
     ml%d: hard error bn %d cs2=%b er=%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 unrecoverable.

Printed 5/17/83                                                 1

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

     ML11 xfer rate error.  The selected transfer rate for the
     ML11 did not conform to the restrictions above.

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.

     The _m_l disk driver requires that the ML-11 be installed on a
     separate RH-11 or RH-70 MASSBUS disk controller.

Printed 5/17/83                                                 2