Data Corruption

Hi There,

I hope someone can shed some light on this for me or at least point me in
thr right direction.

Out of about 100 clients, 10 of them are regurlary having problems with
their tables getting corrupted. They are all using our system over a
network and in most cases the server machine is being used as a workstation.

The strange thing about the corruption is that the dbf is still ok to be
opened through fox and can be browsed, but it is as though a section of
memory has been slotted into the middle of the table. No data is actually
being lost, just this bad data being added in; usually somewhere near the
middle. Sometimes we can read what the bad data is; one time it looked like
registry entries, the other it actually looked like some of our code!

Would incorrect shutdowns cause this, or scandisk.

If anyone has seen similar or has any ideas, please let me know.

Thanks in advance.

David Gouge

Rick
Wed Aug 06 07:37:41 CDT 2003

David,
Also check for a virus checker running. =
http://support.microsoft.com/default.aspx?scid=3Dkb;en-us;321550 - =
"HOWTO: Optimize Visual FoxPro Applications While Using Norton AntiVirus =
2002" While this information is for a specific version of Norton AV, it =
also can apply to other AV apps depending on how they are implemented =
and how they can be configured.

Rick

"David Gouge" <dave@chasebs.com> wrote in message =
news:O015XPAXDHA.656@tk2msftngp13.phx.gbl...
> Hi There,
>=20
> I hope someone can shed some light on this for me or at least point me =
in
> thr right direction.
>=20
> Out of about 100 clients, 10 of them are regurlary having problems =
with
> their tables getting corrupted. They are all using our system over a
> network and in most cases the server machine is being used as a =
workstation.
>=20
> The strange thing about the corruption is that the dbf is still ok to =
be
> opened through fox and can be browsed, but it is as though a section =
of
> memory has been slotted into the middle of the table. No data is =
actually
> being lost, just this bad data being added in; usually somewhere near =
the
> middle. Sometimes we can read what the bad data is; one time it =
looked like
> registry entries, the other it actually looked like some of our code!
>=20
> Would incorrect shutdowns cause this, or scandisk.
>=20
> If anyone has seen similar or has any ideas, please let me know.
>=20
> Thanks in advance.
>=20
> David Gouge
>=20
>

Dan
Wed Aug 06 07:45:05 CDT 2003

I have this problem with one of my customers. Two of the DBF files cannot
even be opened. VFP recommends using a 3rd-party repair tool. Does anyone
have any suggestions of what software is good for repairing bad tables?
Secondly is this a good idea, to even try to repair?

Thx in advance
Dan Tallent



"Stefan Wuebbe" <stefan.wuebbe@gmx.de> wrote in message
news:OoPDUyAXDHA.3232@tk2msftngp13.phx.gbl...
> > Would incorrect shutdowns cause this, or scandisk.
>
> Right, rather the first than Scandisk, I think. In general IMO this
> type of corruption is almost always caused by failed attempts to
> write files from memory back to disk.
> Besides power failures and incorrect shutdowns that can be any
> kinds of network or hardware problems or GPFs caused by
> unstable OS and driver setups, too.
>
>
> -Stefan
>
>
> "David Gouge" <dave@chasebs.com> schrieb im Newsbeitrag
> news:O015XPAXDHA.656@tk2msftngp13.phx.gbl...
> > Hi There,
> >
> > I hope someone can shed some light on this for me or at least point me
in
> > thr right direction.
> >
> > Out of about 100 clients, 10 of them are regurlary having problems with
> > their tables getting corrupted. They are all using our system over a
> > network and in most cases the server machine is being used as a
> workstation.
> >
> > The strange thing about the corruption is that the dbf is still ok to be
> > opened through fox and can be browsed, but it is as though a section of
> > memory has been slotted into the middle of the table. No data is
actually
> > being lost, just this bad data being added in; usually somewhere near
the
> > middle. Sometimes we can read what the bad data is; one time it looked
> like
> > registry entries, the other it actually looked like some of our code!
> >
> > Would incorrect shutdowns cause this, or scandisk.
> >
> > If anyone has seen similar or has any ideas, please let me know.
> >
> > Thanks in advance.
> >
> > David Gouge
> >
> >
>

Mike
Wed Aug 06 20:40:25 CDT 2003

In Earlier versons of FoxPro using a "Replace for" would
corrupt tables I think even "Delete For". To solve this I
went through my code and put it into a loop to replace or
delete.

I am not sure if that is an issue in Visual 6 and up. I
have found that the Database container always got corrupt!
I keep a copy of the container 3 files and over write the
corrupt ones, that is how I have delt with it.
I would always back up the database container when ever I
did anything with it.

With FoxPro 8 I Don't know I hope it is more stable. I
have not been working with it very long, as a habit I
back up the database Container all the time. I hope they
fixed this problem.

I lean toward using SQL server as a back end if your
Clients can afford it.



>-----Original Message-----
>Hi There,
>
>I hope someone can shed some light on this for me or at
least point me in
>thr right direction.
>
>Out of about 100 clients, 10 of them are regurlary
having problems with
>their tables getting corrupted. They are all using our
system over a
>network and in most cases the server machine is being
used as a workstation.
>
>The strange thing about the corruption is that the dbf
is still ok to be
>opened through fox and can be browsed, but it is as
though a section of
>memory has been slotted into the middle of the table.
No data is actually
>being lost, just this bad data being added in; usually
somewhere near the
>middle. Sometimes we can read what the bad data is; one
time it looked like
>registry entries, the other it actually looked like some
of our code!
>
>Would incorrect shutdowns cause this, or scandisk.
>
>If anyone has seen similar or has any ideas, please let
me know.
>
>Thanks in advance.
>
>David Gouge
>
>
>.
>

Stefan
Thu Aug 07 03:57:33 CDT 2003


"Dan Tallent" <dtallent@NOTEarthlink.net> schrieb im Newsbeitrag
news:uAgsxhBXDHA.1940@TK2MSFTNGP10.phx.gbl...
> I have this problem with one of my customers. Two of the DBF files cannot
> even be opened. VFP recommends using a 3rd-party repair tool. Does
anyone
> have any suggestions of what software is good for repairing bad tables?

In my experience Recover at www.abri.com and FoxFix
at www.hallogram.com both work fine.

See also http://fox.wikis.com/wc.dll?Wiki~NotATable~VFP
and "file structures" in the Vfp help

> Secondly is this a good idea, to even try to repair?

You're right, it might make sense to try to find the (hardware,
network,operating system,driver, maybe anti-virus tool) issues
first.


-Stefan

Stefan
Thu Aug 07 03:57:22 CDT 2003


"Mike" <Mike@cresset.com> schrieb im Newsbeitrag
news:060801c35c84$dfe19fd0$a501280a@phx.gbl...
> In Earlier versons of FoxPro using a "Replace for" would
> corrupt tables I think even "Delete For". To solve this I
> went through my code and put it into a loop to replace or
> delete.
> I am not sure if that is an issue in Visual 6 and up.

I never experienced such a correlation.
Not in Vfp6/7/8 but also not with FoxPro 2.6, where
I used Replace For and Delete For a lot.


-Stefan

Dan
Thu Aug 07 09:34:03 CDT 2003

Thx for the help. I'll take a look at the sites.

Thx again,
Dan


"Stefan Wuebbe" <stefan.wuebbe@gmx.de> wrote in message
news:%23LI7HIMXDHA.1900@TK2MSFTNGP10.phx.gbl...
>
> "Dan Tallent" <dtallent@NOTEarthlink.net> schrieb im Newsbeitrag
> news:uAgsxhBXDHA.1940@TK2MSFTNGP10.phx.gbl...
> > I have this problem with one of my customers. Two of the DBF files
cannot
> > even be opened. VFP recommends using a 3rd-party repair tool. Does
> anyone
> > have any suggestions of what software is good for repairing bad tables?
>
> In my experience Recover at www.abri.com and FoxFix
> at www.hallogram.com both work fine.
>
> See also http://fox.wikis.com/wc.dll?Wiki~NotATable~VFP
> and "file structures" in the Vfp help
>
> > Secondly is this a good idea, to even try to repair?
>
> You're right, it might make sense to try to find the (hardware,
> network,operating system,driver, maybe anti-virus tool) issues
> first.
>
>
> -Stefan
>