Date: Mon, 10 May 1999 19:38:26 -0700 (PWT) From: Matthew Jacob <mjacob@feral.com> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Stan Shkolny <stan@osgroup.com>, hackers@FreeBSD.ORG Subject: Re: Which O/S routines are subject to change? Message-ID: <Pine.LNX.4.04.9905101932180.15190-100000@feral.com> In-Reply-To: <199905110231.TAA73624@apollo.backplane.com>
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On Mon, 10 May 1999, Matthew Dillon wrote:
> :> Any of them can change, but I excpect it to settle down in a year or two.
> :>
> :
> :It sounds like we might consider a DDI/DKI set of definitions.
>
> Yes, but not until things settle down in a year or two. Until
> then, trying to impose a toolkit DDI on the kernel will only make
> everyone's life harder. The VFS system is almost certainly going to
> be shredded this year and I'm sure it is going to take a year to cleanup
> and refine newbus & dma handling.
>
Oh, absolutely, but you can also cut it a couple of different ways. You
can define things that really are unlikely to change (like memset or
copyin) as being 'STANDARD' interfaces and define interfaces that probably
won't change (e.g. a device's open routine) as being 'STABLE' and other
mechanisms as different.... A pretty useful classification scheme is in
the section 5 'attributes' man page in Solaris, e.g.:
Release Level
Stability for Incompatible
Level Changes Other Comments
....
Stable Major (x.0) Incompatibilities are
exceptional.
Evolving Minor (x.y) Migration advice might
accompany an incompa-
tibility.
....
Stable A Stable interface is a mature interface under
Sun's control. Sun will try to avoid non-
upwards-compatible changes to these interfaces,
especially in minor or micro releases.
If support of a Stable interface must be discon-
tinued, Sun will attempt to provide notification
and the stability level changes to Obsolete.
Evolving An Evolving interface may eventually become
Standard or Stable but is still in transition.
...
It gets even more complex if you actually can dig up Sun's internal
classification levels of interfaces (where terms like 'Contract Private'
and 'Uncommitted' get bandied about....)...
Sorry- this gets offtopic from the original question... It'd be a good
thing to have though......
;
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