NAME

dkctl − control special disk operations

SYNOPSIS

/usr/etc/dkctl disk command

DESCRIPTION

dkctl is used to enable or disable special disk operations. In particular, enabling or disabling of verified writes (write check functionality) is controlled by this program. 

The disk specification here is a disk name of the form /dev/rxxnp, where xx is the controller device abbreviation (xd, sd, etc.), n is the disk number, and p is the partition to which the operation applies.  The partition specification is simply the letter used to identify that partition in the standard UNIX system nomenclature. 

SUPPORTED COMMANDS

wchkThis function enables write checking for disks that support it for the named disk partition. This means that disk partitions with this feature enabled, all writes are verified to have been correctly written on the disk. This operation emphasizes data reliability over performance, although for each implementation, the fastest reasonable method will be used (i.e., implemented in hardware, if possible). 

−wchkThis disables write check functionality for the named disk partition. 

spinSame as -spin. 

-spinThis function allows the administrator to take the particular device containing the named partition offline. The drive is spun back up on the next access. 

suspendThis function allows the administrator to suspend all I/O operations to the I/O bus containing the named partition. 

resumeThis function allows the administrator to resume I/O operations to the I/O bus containing the named partition. 

highThis function places a higher priority for all operations which are destined to the named disk partition.  High priority implies that the I/Os to this disk will be started in front of any other operations destined for normal priority devices on the same I/O bus.  Issuing two operations to a single high priority disk may cause the second command to be started before the first.  This operation mode emphasizes the performance of particular drives over others and may be useful in performance tuning. 

-highThis disables the high priority functionality for the named disk partition. 

BUGS

Use of the dkctl command requires super-user permissions. 

There are many other features this program could control, and may in the future. 

FILES

/dev/rxxnp

SEE ALSO

dkio(4S), sd(4S), xd(4S)

Solbourne Computer, Inc.  —  10 Jan 1994