DLL/GPL/proprietary link revisited

[Rasmus Emil Møller]

Hello to the list,

I am an open-source newbie, please forgive me if my question is off-topic.
However, it is in the line of a few, long recent threads of this list.

The ERP system I am managing is running on a DBM from a major vendor.
For database backup/restore purposes the DBM provides a simple, well-
documented generic DLL interface, so any backup vendor can provide a
DLL and the user (me) can fire off commands like:

... backup database my_db_name load vendor_dll_name.dll

We already use a backup vendor providing this DLL - it works fine.

I just noticed that the backup data is highly compressible, and that
neither of the two vendors apply any compression to the data.

I searched and found that LZO compression (GPL'ed) could indeed
compress our backup data to a third of the original size and time spent.

I want to make a pass-through DLL to be called by the DBM,  using
the LZO GPL code to compress/decompress the data, in turn calling
the backup vendor DLL with the compressed data.

Naturally, my DLL would have to be GPL'ed as it is a derivative work.
But is it legal for me at all? Or is it an improper use of Mr. Oberhumers
work on LZO to address the shortcomings of proprietary programs?

Ideally, one of the two vendors would adopt my dll and support it
for a price - otherwise my management would probably not dare
to implement it. sigh.

sorry for the long post

Rasmus Møller
Topdanmark

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