2.11BSD#431 - /usr/man/cat4/hk.0

HK(4)		    UNIX Programmer's 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 par-
     titions 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 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 the buffer must begin on a word (even) boundary,
     and counts should be a multiple of 512 bytes (a disk sec-
     tor).  Likewise seek calls should specify a multiple of 512
     bytes.

DISK SUPPORT
     Disks must be labeled using either the standalone disklabel
     program on the boot tape or with the disklabel(8) program.
     There are no partition tables coded into the hk drivers,
     these must be placed on the drive with disklabel.

     Traditionally the hk?a partition is used for the root
     filesystem, the b partition as a swap area and the c parti-
     tion for disk to disk copying (it spans the entire disk).


Printed 11/26/99	December 28, 1997			1


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


     The kernel uses the c partition to access the bad block
     information stored at the end of some packs.  Extreme care
     must be taken when creating file systems on this partition
     to avoid overwriting any bad block information present.
     User data should use the h partition which should be at
     least one track (one cylinder might be best) shorter than
     the c partition.

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), disklabel(8)

DIAGNOSTICS
     hk%d%c: hard error sn%d cs2=%b ds=%b er=%b.  An unrecover-
     able 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 occur-
     ing should be checked to see if certain cylinders on the
     pack, spots on the carriage of the drive or heads are indi-
     cated.

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


Printed 11/26/99	December 28, 1997			2


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


     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.


Printed 11/26/99	December 28, 1997			3