M DISKBLOCK, UTILITIES, Editor amd performance tester for ODS and Foreign disks   3   DISKBLOCK is a low level disk block editing tool.   J   V6.2 of Diskblock has been updated to support OpenVMS on IA64 as well asI   Alpha and VAX. There is a single VMSINSTAL kit that will install on all    three architectures   J   Diskblock can be used to read, modify and write LBNs on a disk or VBN's E   in a file.  It can also carry out read, write and seek performance     measurements.   I   Diskblock ingores all locking activity on the selected Disk or File, it K   can access and modify ODS2 and ODS5 data structures such as file headers  N   and it can read, write and test individual shadow set members independently!  D   There is a buffer which holds a copy of the block which you read, F   you can modify the contents of this buffer using EXAMINE and DEPOSITI   commands and then REWRITE it to the same block, WRITE it to a different G   block or SELECT a new disk or file and WRITE the buffer to any block.   F   When you SELECT a disk, diskblock will attempt to map the Index FileJ   If it is successful then any command which requires an LBN (READ, WRITE,I   COPY etc...) will also accept a FID and operate on the appropriate file ?   header.  This will work even if the disk is mounted /FOREIGN.   I   There are commands to SAVE and RESTORE the buffer so that you can keep  J   a copy of the original block and undo changes if they do not work as you	   expect.   H   There is a CHECKSUM command to enable you to recalculate the checksums1   for ODS2 and ODS5 file headers and home blocks.   @   There is a DIRECTORY command which will find the header for a -   file (even if the disk is mounted /foreign)   H   There is a COPY command which will enable you to treat any block on a L   disk as a file header and copy the LBNs described by its mapping pointers 7   to a new file (even if the disk is mounted /foreign).    C   There is a SEARCH command which will search the entire disk/file  E   (or any range of blocks) for a particular string or integer or file 	   header.   H   There is a TEST command which will carry out performance testing.  YouI   may specify queue lengths, I/O sizes, read/write ratios and seek types  A   and Diskblock will report throughput and bandwidth to the disk.   ;   Because of its potential to corrupt disks you should only B   use Diskblock in extreme desperation or on a disk which you have   backed up.     -   You need LOG_IO privilege to run DISKBLOCK.   @   Diskblock has an extensive help file with further information.      