hp —
MASSBUS disk interface
hp0 at mba0 drive 0
hp* at mba? drive ?
The hp driver is a generic MASSBUS disk driver which
  handles the standard DEC controllers. It is typical of a block-device disk
  driver; block I/O is described in
  physio(4).
The script
    MAKEDEV(8) should be used
    to create the special files; if a special file needs to be created by hand
    consult mknod(8). It is
    recommended as a security precaution to not create special files for devices
    which may never be installed.
The first sector of each disk contains both a first-stage
    bootstrap program and a disk label containing geometry information and
    partition layouts (see
    disklabel(5). This
    sector is normally write-protected, and disk-to-disk copies should avoid
    copying this sector. The label may be updated with
    disklabel(8), which can
    also be used to write-enable and write-disable the sector. The next 15
    sectors contain a second-stage bootstrap program.
During autoconfiguration or whenever a drive comes on line for the first time,
  or when a drive is opened after all partitions are closed, the first sector of
  the drive is examined for a disk label. If a label is found, the geometry of
  the drive and the partition tables are taken from it. If no label is found, a
  fake label is created by the driver, enough so that a real label can be
  written.
The hp?a partition is normally used for the root file system, the
    hp?b partition as a paging area, and the hp?c partition for pack-pack
    copying (it maps the entire disk). On disks larger than about 205 Megabytes,
    the hp?h partition is inserted prior to the hp?d or hp?g partition; the hp?g
    partition then maps the remainder of the pack.
  - /dev/hp[0-7][a-h]
- block files
- /dev/rhp[0-7][a-h]
- raw files
  - hp%d%c: hard error %sing fsbn %d [of %d-%d] (hp%d bn %d cn %d tn %d sn %d)
    mbsr=%b er1=%b er2=%b.
- An unrecoverable error occurred during transfer of the specified
      filesystem block number, which is a logical block number on the indicated
      partition. If the transfer involved multiple blocks, the block range is
      printed as well. The parenthesized fields list the actual disk sector
      number relative to the beginning of the drive, as well as the cylinder,
      track and sector number of the block. The MASSBUS status register is
      printed in hexadecimal and with the error bits decoded if any error bits
      other than MBEXC and DTABT are set. In any case the contents of the two
      error registers are also printed in octal and symbolically with bits
      decoded. (Note that er2 is what old RP06 manuals would call RPER3; the
      terminology is that of the RM disks). The error was either unrecoverable,
      or a large number of retry attempts (including offset positioning and
      drive recalibration) could not recover the error.
- hp%d%c: soft ecc reading fsbn %d [of %d-%d] (hp%d bn %d cn %d tn %d sn
    %d).
- A recoverable ECC error occurred on the specified sector of the specified
      disk partition. If the transfer involved multiple blocks, the block range
      is printed as well. The parenthesized fields list the actual disk sector
      number relative to the beginning of the drive, as well as the cylinder,
      track and sector number of the block. This happens normally a few times a
      week. If it happens more frequently than this the sectors where the errors
      are occurring should be checked to see if certain cylinders on the pack,
      spots on the carriage of the drive or heads are indicated.
Thehp driver appeared in
  4.0BSD.
A new hp driver showed up in
    NetBSD 1.2.
DEC-standard bad144(8)
  bad-block handling should be used.
DEC-standard error logging should be supported.
A program to analyze the logged error information (even in its
    present reduced form) is needed.