man(1) Manual page archive


     RP(4)                                                       RP(4)

     NAME
          rp - RP-11/RP03 moving-head disk

     DESCRIPTION
          The files rp0 ... rp7 refer to sections of RP disk drive 0.
          The files rp8 ... rp15 refer to drive 1 etc.  This allows a
          large disk to be broken up into more manageable pieces.

          The origin and size of the pseudo-disks on each drive are as
          follows:

               disk start     length
               0    0    81000
               1    0    5000
               2    5000 2000
               3    7000 74000
               4-7  unassigned

          Thus rp0 covers the whole drive, while rp1, rp2, rp3 can
          serve usefully as a root, swap, and mounted user file system
          respectively.

          The rp files access the disk via the system's normal buffer-
          ing 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 therefore raw
          I/O is considerably more efficient when many words are
          transmitted.  The names of the raw RP files begin with rrp
          and end with a number which selects the same disk section as
          the corresponding rp file.

          In raw I/O the buffer must begin on a word boundary.

     FILES
          /dev/rp?, /dev/rrp?

     SEE ALSO
          hp(4)

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