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LWN.net Weekly Edition for May 23, 2013
An "enum" for Python 3
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A look at the PyPy 2.0 release
Char devices for network interfaces
Posted Oct 27, 2009 19:18 UTC (Tue) by dlang (✭ supporter ✭, #313)
there are a handful of cases (USB devices) where simple detection order is non-determinant, but the vast majority of devices fall into two categories
1. a single interface
2. simple detection order produces reliable device numbering
yes, when you change a card it can change the detection order, but that is true for every operating system, and is seldom a real big problem (because people are used to dealing with it)
the attempts to solve this problem end up causing more grief for many people, so much so that I doubt if the solution is worth it.
when you have a fairly rare problem to start with, your solution must be _very_ reliable for it to be better than doing nothing.
if you have a problem that affect 0.1% of the population, and your solution has an error rate of 1%, you have made life worse for 0.9% of the population.
this assumes that your solution is something that is deployed everywhere. creating a solution like this and having it option, used only in the case where people are experiencing problems to start with, you have a very different situation, then you are making life better for 0.099% of the population and not making life worse for anyone.
Posted Oct 28, 2009 13:26 UTC (Wed) by mdomsch (subscriber, #5920)
By not changing how the kernel chooses to name devices, I can't break things for anyone. If they like the non-deterministic nature of device naming, and it works for them, great.
But that 0.1% you refer to, is around 20% of Dell's server sales, likewise for other server companies. Not insignificant to that userbase.
I'm not suggesting making this optional. I'm suggesting we add it into the base udev rules, where, if a platform provides additional information to help is provide "better" names, in addition to the normal kernel-provided names, that thsoe "better" names can be used too. For various definitions of "better", all simultaneously.
Yes, other OSs have this same problem too. I get to discuss the problem and approaches at solutions with them also.
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