Subject Re: [IB-Architect] Backward compatability with previous versions of gdb files
Author Jim Starkey
At 02:34 AM 4/30/00 -0000, Dominique Louis wrote:
> just wondering if there were any plans to make any new servers
>compatible with older gdb files.
>The first time the server encounters an older version gdb file, it
>should prompt the user if this file should be updated to the newer
>version. If this cannot be built into the server maybe someone could
>point me in the direction of where such a handy utility would be.
>The idea ( as good as it is ) of backing up my old database before
>upgrading to the newer version of the server basically takes too much
>planning. Most users would like to plug and play the new version of
>the server.
>If interbase is to make it as a minimum administration database it
>to support backward compatability in some way without necessitating a
>back-up before hand ( though I have said this is a good practice ).
>Maybe the new server ( I don't mean IB 6 ) can offer to make a back
> before doing the conversion as well.

Backwards compatibility has always been part of the Interbase
architecture. All calls go through what is prosaically called
the Y-valve (story on request) which determines which subsystem
to pass the calls through. The Y-valve actually has no intelligence--
it just calls successive subsystems to find one willing to handle
the connect string. Among the system systems polled (at various
points in Interbase history):

1. TCP remote
2. DECnet remote
3. Apollo Domain remote (sigh, long gone)
4. LAN Manager remote
5. Current engine version
6. Prior engine version
7. Even more prior engine version (we rarely supported more than 2)
8. Oracle gateway
9. Rdb gateway

A number of these have whithered away, the but the architecture
remains in place.

So the answer is: Of course!

Jim Starkey