RK(4)							     Kernel Interfaces Manual							     RK(4)

NAME

       rk - RK-11/RK05 disk

SYNOPSIS

       /sys/conf/SYSTEM:
	    NRK  rk_drives # RK05

       /etc/dtab:
	    #Name Unit# Addr   Vector Br Handler(s)	 # Comments
	    rk	  ?	177400 220    5  rkintr 	 # rk05

       major device number(s):
	    raw: 15
	    block: 6
       minor device encoding:
	    specifies drive: <rk_drive>

DESCRIPTION

       Minor  device  numbers  are  drive numbers on one controller.  The standard device names begin with ``rk'' followed by the drive number and
       then the letter "h".  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 rk driver does not support pseudo-disks (partitions).  Each file rk?h refers to the entire drive as	a  single  sequentially  addressed
       file.  Each drive has 4872 512-byte blocks.

       It's not clear what one would do with one of these drives if one had one ...

FILES

       /dev/rk[0-7]h	   block files
       /dev/rrk[0-7]h	   raw files
       /dev/MAKEDEV	   script to create special files
       /dev/MAKEDEV.local  script to localize special files

SEE ALSO

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

DIAGNOSTICS

       rk%d:  hard  error  sn%d  er=%b ds=%b.  An unrecoverable error occurred during transfer of the specified sector of the specified disk.  The
       contents of the two error registers are also printed in octal and symbolically with bits decoded.  The error was either unrecoverable, or a
       large number of retry attempts 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.

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.

3rd Berkeley Distribution					  August 20, 1987							     RK(4)