regular ABI vs modversions
Posted Feb 7, 2003 1:04 UTC (Fri) by giraffedata
In reply to: The return of modversions
Parent article: The return of modversions
I think you're proposing that instead of having complicated, imperfect mechanisms to be sure your base kernel has the same printk() that your loadable module expects, just have one standard, documented printk().
It goes to the heart of Linux philosophy that there are many variations of Linux available and even within one development stream, developers do not constrain themselves with backward compatibility. Linux is not like commercial software products.
I have a great anecdote about the difference. I developed a filesystem driver as a loadable kernel module for Linux and an equivalent one for AIX. With Linux, I had to do some nontrivial recoding several times to make it work with the latest 2.4 kernel or with someone else's variation on 2.4. With AIX, I loaded the module that was written for, compiled for, and tested on an AIX 4.3.3 32 bit UP system into an AIX 5.1 64 bit MP system. It worked fine. AIX 5.1 has a lot of improvements over 4.3.3 in the filesystem driver interface, but none of them broke binary compatibility.
This and related issues mean there will probably be a lot more people using the AIX implementation of this technology than the Linux one.
IBM Almaden Research Center
San Jose CA
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