HK(4)							     Kernel Interfaces Manual							     HK(4)

NAME

       hk - RK6-11/RK06 and RK07 moving head disk

SYNOPSIS

       /sys/conf/SYSTEM:
	    NHK  hk_drives # RK611, RK06/07

       /etc/dtab:
	    #Name Unit# Addr   Vector Br Handler(s)	 # Comments
	    hk	  ?	177440 210    5  hkintr 	 # rk611/711 rk06/07

       major device number(s):
	    raw: 13
	    block: 4
       minor device encoding:
	    bits 0007 specify partition of HK drive
	    bits 0070 specify HK drive

DESCRIPTION

       Files  with  minor  device numbers 0 through 7 refer to various portions of drive 0; minor devices 8 through 15 refer to drive 1, etc.  The
       standard device names begin with ``hk'' followed by the drive number and then a letter a-h for partitions 0-7 respectively.  The  character
       ? stands here for a drive number in the range 0-7.

       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 therefore 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 the buffer must begin on a word (even) boundary, and counts should be a multiple of 512 bytes (a disk  sector).   Likewise  seek
       calls should specify a multiple of 512 bytes.

DISK SUPPORT

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

       RK06 partitions:
	    disk   start  length       cyls  comments
	    hk?a       0    8316    0 - 125  root
	    hk?b    8316    8316  126 - 251  swap
	    hk?c       0   27126    0 - 410* whole pack plus badsect track
	    hk?d  unused
	    hk?e  unused
	    hk?f  unused
	    hk?g   16632   10428  251 - 409  tmp
	    hk?h       0   27060    0 - 409  whole pack minus badsect track

       RK07 partitions:
	    disk   start  length       cyls  comments
	    hk?a       0    8316    0 - 125  root
	    hk?b    8316    8316  126 - 251  swap
	    hk?c       0   53790    0 - 814* whole pack plus badsect track
	    hk?d  unused
	    hk?e  unused
	    hk?f  unused
	    hk?g   16632   37092  252 - 813
	    hk?h       0   53724    0 - 814  whole pack minus badsect track

       Those  partitions marked with an asterisk (``*'') allow access to bad block information stored at the end of some packs.  Extreme care must
       be taken when creating file systems on these partitions to avoid overwriting any bad block information present.	I general it's best to use
       newfs(8) to create file systems since it uses the ``safe'' partition sizes recored in /etc/disktab.

FILES

       /dev/hk[0-7][a-h]   block files
       /dev/rhk[0-7][a-h]  raw files
       /dev/MAKEDEV	   script to create special files
       /dev/MAKEDEV.local  script to localize special files

SEE ALSO

       ra(4), ram(4), rk(4), rl(4), rx(4), si(4), xp(4), dtab(5), autoconfig(8)

DIAGNOSTICS

       hk%d%c:	hard error sn%d cs2=%b ds=%b er=%b.  An unrecoverable error occurred during transfer of the specified sector of the specified disk
       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.

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

       hk%d: not ready.  The drive was spun down or off line when it was accessed.  The i/o operation is not recoverable.

       hk%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.

       hk%d%c: soft ecc sn%d.  A recoverable ECC error occurred on the specified sector of 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 occuring should be checked to see if certain
       cylinders on the pack, spots on the carriage of the drive or heads are indicated.

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.

       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 pre-
       fer, and this would make packs more portable.

3rd Berkeley Distribution					  January 3, 1993							     HK(4)