  Causes of Invalid Bootblock? 
 The Question is:
 
On trying to boot the system using the boot command (boot dka0) i recieve the
 following message "block 0 of dka0.0.0.6.0 is not a valid boot block bootstrap
 failure"
What are the common causes of this and how do i fix it?
 
 The Answer is :
 
  The two most common cause of this errors: block zero was never
  initialized and the target disk is not an OpenVMS system disk,
  and block zero was overwritten and no longer valid.
 
  Errant boot block writes obviously occur when a logical I/O
  operation targets disk block zero -- various causes of this bug
  have been seen within application code over the years, of course.
 
  Bootstrapping another system disk or the distribution media and
  mounting the errant disk is the most common solution for a
  corrupted bootblock, and using the WRITEBOOT utility to reset
  the bootblock.
 
  If there is no boot block, then you will want to install OpenVMS
  (if appropriate) onto the disk.
 
 Answer written or last revised on  17-DEC-2003 
