Hi

> I've never heard of NTBACKUP - ... And I also have a system tool called

merely "Backup" which I never use.

This is what was called NTBACKUP since NT 4.0.
It is really powerful, since it is afaik the only backup programm which can
make use of volume shadow copies at that time and can also backup Exchange
servers without additional software - if the exchange admin tools are
installed on the machine.

> I'm not sure I understand you but you appear to be confirming what I have

said. i.e. running processes continue while the copying is taking place.

This is true, but it is NO problem. Why should it? You can keep updating
rows while other transactions still see old versions in an RDBS. This is
true for volume shadow copies also. They appear to be some kind of
transactions to the file system. The backup programm can read the NOT
FURTHER MODIFYING file, while the other processes can keep modifing the
files - including databases.

> The file in total is not locked but disk sector by disk sector it IS

locked while copying, this is an OS thing which will not change.

Are you sure about this? I don't really know, how volume shadow copies are
implemented, but my understanding of all the white papers I have read
suggest, that it's primary design goal was not to change the behaviour of
already running processes - including having no additional locks. This CAN
be done by the os, if it simply reads the existing blocks before overwriting
them and stalling the writing process for that short time.

> I think you might be confusing other things with regard to power failure

and the forced writes property.

Because of the semantics of volume shadow copies of drives like transactions
in database systems, the state of the file (visible for the backup process)
will stall at the time, the volume shadow copy was created. Just as if the
power had failed at that very time.

Regards,
Steffen