Re: [RFC][5/11][MANUX] Kernel compatibility : major/minor numbers

From: One Thousand Gnomes
Date: Tue Apr 15 2014 - 11:06:49 EST


> In order to associate devices to their files, the Linux kernel uses
> their major and minor numbers. However, mine doesn't; instead, I've
> attributed myself a single group of values (major=0, minor=0, for both
> character-mode and block-mode special files), with the meaning (for the
> userspace) "you cannot identify the content of this file based on its
> major and minor numbers".

If you are using the Linux ABI then you'll hit cases (in particular tty
cases) where the ABI/API knows about major/minor numbers. In addition the
standards and common sense together pretty much imply that you need each
device to at least have a unique identifier.

Finally you need major/minor numbers to NFS serve to a diskless client.

Most Linux device numbering beyond that is basically dynamic so it
probably does't matter that much for things you concoct - providing in
som cases your /proc table of major numbers is right.

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