Data corruption

[Brian K. White]

----- Original Message ----- 
From: "Joe Chasan" <joe at magnatechonline.com>
To: "Kenneth Brody" <kenbrody at bestweb.net>
Cc: "'Filepro-List at Lists. Celestial. Com'" <filepro-list at lists.celestial.com>
Sent: Wednesday, December 12, 2007 12:28 PM
Subject: Re: Data corruption


> On Tue, Dec 11, 2007 at 01:05:22PM -0500, Kenneth Brody wrote:
>> Quoting Don Coleman (Tue, 11 Dec 2007 12:35:51 -0500):
>> 
>> > Client had a hard drive fail over the weekend.  I have identified some data
>> > corruption in an archive file at this point.  Most of the corrupted records
>> > are in small batches of 20-50 records although a few are single individual
>> > records.  I am unable to delete the corrupted records (nothing happens on
>> > the screen).  Is there any way to get rid of these?  The hard drive failed
>> > during the backup and I can piece the data together if I can eliminate the
>> > corrupted records.
>> >
>> > Windows 2003 server, fPv5.0.13, WIN2000 & WINXP Pro clients.
>> 
>> Depending on how the records are corrupted, filePro may think that they
>> are already deleted.  In that case, update the records to create them
>> and then delete them again.
> 
> since this keeps coming up every few months, would it be a big deal for
> fp to write the record space out with blanks, then delete it, instead of 
> just assuming it is empty/already deleted and not doing anything?

I think it's useful that fp doesn't touch the data in various places like this.
If the data is inconsistent, then I don't _want_ it to be modified except by me.
If the data is consistent then there is no problem.
Anyone is free to write their own low level data fix-up processes using fp itself by mapping the key file to a non-filepro file and/or via direct file i/o or import/export any time they want to make the data consistent. fp can't magically make the data consistent. Only the developer who designed or at least fully understands the data structure can do that.

Brian K. White    brian at aljex.com    http://www.myspace.com/KEYofR
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