Re: Switching the default startup method
Wouter Verhelst wrote:
> On Mon, Aug 24, 2009 at 03:34:51PM +0200, Raphael Hertzog wrote:
>> On Mon, 24 Aug 2009, Bernd Zeimetz wrote:
>> With dependency based ordering, you just state the dependencies and you
>> let it figure out the order.
>>
>>> There are advantages to dependency-based boot systems, sure; but there
>>> are advantages to *not* having that, too (e.g., it is more
>>> deterministic, and therefore easier to debug).
>> Well, both are deterministic but they do not decide of the ordering in the
>> same way and it's just easier for our brains to represent a number-based
>> sequence.
>
> Sorry, but dependency-based boot systems are *not* deterministic.
>
> Let's assume the following:
>
> - initscript a depends on b
> - initscript c declares that it wants a to be started first if it is
> installed, but that it is not a problem if it isn't installed.
>
> Now we may have either of the following situations, depending on whether
> the user does or does not install recommendations:
>
> - b is started first, then a, then c
> - b is started, and c too. The order depends on coincidence, since there
> is no relationship between the two
>
> If initscript c should actually declare a dependency on initscript b,
> then you have a bug that the maintainer may find himself hard-pressed to
> reproduce, simply because he does have the package containing initscript
> a installed.
If there is a bug in the dependencies of c, then there is indeed a
problem that should get fixed. I don't see what you try to prove with
that though?
Cheers
Luk
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