Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!csn!ccncsu!purdue!mentor.cc.purdue.edu!noose.ecn.purdue.edu!samsung!usc!apple!apple.com!jms From: jms@apple.com (John Michael Sovereign) Newsgroups: comp.unix.aux Subject: Re: guidelines for binary compatibility.... Message-ID: <13084@goofy.Apple.COM> Date: 16 Apr 91 17:18:16 GMT Sender: usenet@Apple.COM Organization: Apple Computer, Inc. Lines: 22 In article <> paul@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@apple.com #include