Hi Giorgio,
On 11/10/18 05:49, Giorgio Garabello via Ql-Users wrote:
But i never keep in my mind to use a "public" fieds to store applicative
dependant info.
Hmm. The backup date is applicable to the file on the hard disc. It
holds information about the file on disc and not about the application.
On various other file systems out in the wild, a similar thing exists -
even on MSDOS there's an "archive" bit to tell some backup program that
the file needs backing up. (If I remember that correctly!)
There'a big difference between an intentional write ( i want to use YOUR
DB,) and a casual overwrite (oh sorry, we are using the same field) don't
think as DBA, thinks as a user that install a lot of sw on his system
without know how these works.
True, but that same user could decide to delete the
database/file/whatever that holds details of the backups. Using the
file's own backup date keeps the data (meta data) as close as possible
to the file it applies to. That is the ideal situation. To my mind anyway.
Any backup program is interesting in two pieces of data about a file,
the last time it was modified and the last time it was backed up. Once
you have those, you have the ability to determine if the file needs to
be backed up. Without those data, the only valid backup is to completely
backup everything on the hard disc.
If any other backup application decides to write it's date to the backup
date, then no harm done.
I agree that any other application could overwrite my backup date, for
example, but it could equally overwrite the file type - preventing me
from EXEC'ing the file, or change the data space value resulting in the
file failing to EXEC or worse, random stack based failures.
So, any of the fields in the file header can be overwritten by anyone,
it's the nature of the beast from 1985 I'm afraid.
Of course this is only philosophy :-)
:o)
sorry for my bad english
Never apologise for bad English, your English is perfectly
understandable. My Italian is limited to please, thank you, have a good
day/evening, happy birthday/Christmas, "two lemon ice creams please" and
"two large glasses of white wine please".
And my (late) step father was from San Remo too!
Cheers,
Norm.
--
Norman Dunbar
Dunbar IT Consultants Ltd
Registered address:
27a Lidget Hill
Pudsey
West Yorkshire
United Kingdom
LS28 7LG
Company Number: 05132767
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