guidelines for binary compatibility....

[John Michael Sovereign]

In article <> paul at taniwha.UUCP (Paul Campbell) writes:
> Every time I go to a developers conference I rail about the A/UX people
> changing the kernel data structures out from under developers feet all
> the time - it's really simple - if you are going to remove/reuse a
> data structure field by all means do it BUT LEAVE A PAD IN ITS PLACE
> don't change the offsets to all the other stuff. However everyone
> nods their heads wisely, sais that they understand the problem and
> nothing ever seems to change.

Speaking from the inside, we did pay attention to this for 2.0.1; there was
even a change which was removed from the release because it (unexpectedly)
broke existing drivers.

We didn't want to pad u_phys, since space in the u-dot is at a premium.
We looked at the fields following u_phys and made a judgment call; I think
the right decision was made -- I haven't heard of any commercial drivers
which were broken.

John Sovereign
jms at apple.com 

#include <std/disclaimer.h>