hugo.larson wrote:

> --- In firebird-support@yahoogroups.com, "Ivan Prenosil"
> <Ivan.Prenosil@...> wrote:
>>> Can I conclude that the Nature of Firbird makes it impossible to
>>> recover deleted or updated records once the database performs a SWEEP?
>> No. Immediately after sweep the data will still be there.
>> They will be overwritten later when FB actually needs
>> to reuse space occupied by them.
>>
>> Ivan
>> http://www.volny.cz/iprenosil/interbase/
>>
> Hello Ivan. In your opinion, does a SWEEP make any difference in
> making it more difficult or impossible to recover committed deleted or
> updated records? I have a very paranoid client. Thanks, Hugo

One of the routes with OTHER databases would just to write a blank record
before deleting, but that does not help with Firebird since it will just write
a new record with blank data, leaving the older copy for those transactions
that may need it. So this is a problem for the completely paranoid client :)

If the machine is sitting on the corner of a desk in the office, with a direct
wireless link, then there are other problems than just being able to see old
records by reading the disk raw :) But the run length coding of the stored
record does mean that access requires some detailed knowledge of what is being
looked for.

Since the database SHOULD be on a secure computer, which has secure remote
means of access so that the data is only accessed via the Firebird clients,
then being able to access raw data direct from the disk would not be possible,
so the information is not recoverable - unless the hard disk is stolen.

It depends on the how paranoid the client is ;)
We actually keep all historic data and just make sure access is secure.

--
Lester Caine - G8HFL
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