radisk(8)						      System Manager's Manual							 radisk(8)

Name
       radisk - Digital Storage Architecture (DSA) disk maintenance

Syntax
       /etc/radisk

       radisk -c LBN length special
       radisk -e special
       radisk -n special
       radisk -r LBN special
       radisk -s LBN length special

Description
       The  Digital  Storage  Architecture (DSA) disk maintenance program provides the essential functions to manage DSA disk devices. The command
       must be used on unmounted disk partitions to insure correct results.

       The LBN is a decimal number that represents the logical block number as reported in the errorlog file.  The LBN is the  actual  disk  block
       number starting from the beginning of the disk.

       The  length  is a decimal number that indicates how many (512 byte) blocks to process.  The length specified may be -1 to indicate the last
       block of the specified partition.

       The special file specified is used with -c, -e, -n, and -r options and indicates an unmounted c partition of  a	character  device  special
       file.

Options
       The following options may be set with

       -c   Clears  a forced error indicator on the range of specified LBNs.  The forced error condition indicates that the data in the disk block
	    is bad.  The disk block is good, but the data can not be read without getting an error detection code (EDC) error.	This  option  will
	    cause  the	forced error condition to be removed.  After the forced error indicator is cleared, the EDC error will not be reported nor
	    will the data be marked as bad.

	    All indications that the data is corrupt are lost.	The data should be restored either by manual methods or with the command. The com-
	    mand affects the integrity of the data on a disk and should be followed by a file system restore if data is affected.

       -e   Sets  the  exclusive  access  attribute  associated  with  the specified disk.  This attribute is provided by multihost controllers to
	    restrict access to a disk to one host.  The command will return a failure status if the disk is already  exclusively  associated  with
	    another  host  or  the underlying controller does not provide multihost support.  If the command is issued to a disk that is currently
	    mounted and the command fails, the disk will no longer be online to this host.  For this reason the -e option should not be issued	to
	    a disk that is mounted.

       n    Clears the exclusive access attribute associated with the specified disk.  If the controller provides multihost support and the exclu-
	    sive access attribute is not set for a particular disk, it would be possible for the disk to be accessed by more than one  host.   The
	    command  will  return  a  failure status if the disk is not currently and exclusively associated with this host or the underlying con-
	    troller does not provide multihost support.

       -r   Replaces a block on the disk specified by LBN. See Restrictions.

       -s   Starts a scan for bad blocks on the specified area on a disk. Bad blocks are disk blocks that have data transfer errors to the  extent
	    that they cannot be relied on.  When a bad block is found, it is replaced and the bad block's LBN is reported.  The LBN specified with
	    the option can be 0 to indicate the first block in the specified partition.  If 0 is specified, however, the program starts  searching
	    from the first block of the partition. The option will accept any valid partition on the disk. This allows any partition to be scanned
	    without scanning the entire disk and ensures that the specified partition is free of bad blocks. As an example, indicates the h parti-
	    tion of the third logical disk unit.

Diagnostics
       The command generates messages when the user is not privileged, when the LBN is not in the specified partition, and when the length exceeds
       the size of the partition.

Restrictions
       You must be in single-user mode when using the and options of the program.  If you are in multiuser mode, hangs the system  and	cannot	be
       killed.	If this happens, you must reboot.

       The option is supported only with those DSA disks which use host-initiated dynamic bad block replacement.

       The and options are only supported on controllers that provide multi-host support.  These options are only supported on HSC Version 5.00 or
       later.

See Also
       dkio(4), ra(4), sdc(4), chpt(8), mount(8), restore(8)
       Guide to System Disk Maintenance

4th Berkeley Distribution														 radisk(8)