hk —
RK6-11/ RK06 and RK07 disk interface
hk0 at uba? csr 0177440 vector rkintr
rk0 at hk0 drive 0
NOTE: This driver has not been ported from 4.4BSD yet.
The hk driver is a typical block-device
    disk driver; block device 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).
Special file names begin with ‘hk’ and
  ‘rhk’ for the block and character files
  respectively. The second component of the name, a drive unit number in the
  range of zero to seven, is represented by a
  ‘?’ in the disk layouts below. The last
  component is the file system partition which is designated by a letter from
  ‘a’ to
  ‘h’. and corresponds to a minor device
  number set: zero to seven, eight to 15, 16 to 23 and so forth for drive zero,
  drive two and drive three respectively. The location and size (in sectors) of
  the partitions for the RK06 and RK07 drives are as follows:
  - RK07 partitions
- 
    
      
        | disk | start | length | cyl |  
        | hk?a | 0 | 15884 | 0-240 |  
        | hk?b | 15906 | 10032 | 241-392 |  
        | hk?c | 0 | 53790 | 0-814 |  
        | hk?d | 25938 | 15884 | 393-633 |  
        | hk?f | 41844 | 11792 | 634-814 |  
        | hk?g | 25938 | 27786 | 393-813 |  
 
- RK06 partitions
- 
    
      
        | disk | start | length | cyl |  
        | hk?a | 0 | 15884 | 0-240 |  
        | hk?b | 15906 | 11154 | 241-409 |  
        | hk?c | 0 | 27126 | 0-410 |  
 
On a dual RK-07 system partition hk?a is used for the root for one
    drive and partition hk?g for the /usr file system. If large jobs are to be
    run using hk?b on both drives as swap area provides a 10Mbyte paging area.
    Otherwise partition hk?c on the other drive is used as a single large file
    system.
  - /dev/hk[0-7][a-h]
- block files
- /dev/rhk[0-7][a-h]
- raw files
  - hk%d%c: hard error %sing fsbn %d[-%d] cs2=%b ds=%b er=%b.
- An unrecoverable error occurred during transfer of the specified
      filesystem block number(s), which are logical block numbers on the
      indicated partition. The contents of the cs2, ds and er registers are
      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.
- rk%d: write locked.
- The write protect switch was set on the drive when a write was attempted.
      The write operation is not recoverable.
- rk%d: not ready.
- The drive was spun down or off line when it was accessed. The I/O
      operation is not recoverable.
- rk%d: not ready (came back!).
- The drive was not ready, but after printing the message about being not
      ready (which takes a fraction of a second) was ready. The operation is
      recovered if no further errors occur.
- rk%d%c: soft ecc reading fsbn %d[-%d].
- A recoverable ECC error occurred on the specified sector(s) in 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
      occurring should be checked to see if certain cylinders on the pack, spots
      on the carriage of the drive or heads are indicated.
- hk%d: lost interrupt.
- A timer watching the controller detected no interrupt for an extended
      period while an operation was outstanding. This indicates a hardware or
      software failure. There is currently a hardware/software problem with
      spinning down drives while they are being accessed which causes this error
      to occur. The error causes a UNIBUS reset, and retry of the pending
      operations. If the controller continues to lose interrupts, this error
      will recur a few seconds later.
Thehk driver appeared in
  4.1BSD.
The write(2) function scribbles
  on the tail of incomplete blocks.
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.
The RK07 g partition size in rk.c disagrees with that in
    /etc/disktab.