Olivier,

> > SQL Message : -820
> > wrong or obsolete version
> >
> > Engine Code : 335544379
> > Engine Message :
> > unsupported on-disk structure for file plan.fdb; found 523, support

10

> >
> > Any ideas why I'm getting this error message, when connecting to the
> > plan.fdb?
>
> ODS 523 versus 10 ?
> Ann ?

I hope I will do.

With Firebird v2.0 adds a new feature which was intended to ensure that
Firebird ODS 11 database and InterBase ODS 11 are never accessed by the
wrong engine. Since the ODS's, though sharing the same heritage, can
NEVER be intermixed -- there have been a changes made by both products
which render the databases incompatible at the file level.

The feature was implemented by adding a signature "bit" to the ODS value
of disk -- once the header is read and the ODS 'validated', the engine
thinks of the database simply as ODS 11/12/13... and reports the same to
an external systems.

Also introduced was the ability to allow for database which were created
from snapshot/alpha builds/releases to be tagged as having a "transient"
ODS structure ("private" is also an option if I recall). Thus, ensuring
that you could not use a database which while based on ODS 11 was not
the final ODS 11 in a production environment.

It is a safety feature -- much like not confusing IB and FB ODS 11 is a
safety feature -- because using a mismatched engine and database could
result in a database looking like guacamole!

The tagging takes the form of a bit mask which is applied to the main
ODS # -- note that 523 is a 512 offset to ODS 11.

Naturally, as the engine works through the alpha/beta and RC stage a
decision will be made about the stability of the ODS and the mask will
be removed accordingly.


Sean