Re: rfc: test whether a device has a partition table

[Linus Torvalds <torvalds@osdl.org>]

On Thu, 25 Sep 2003, Andries Brouwer wrote:
> 
> My post implicitly suggested the minimal thing to do.
> It will not be enough - heuristics are never enough -
> but it probably helps in most cases.

I don't mind the 0x00/0x80 "boot flag" checks - those look fairly obvious
and look reasonably safe to add to the partitioning code.

There are other checks that can be done - verifying that the start/end
sector values are at all sensible. We do _some_ of that, but only for
partitions 3 and 4, for example. We could do more - like checking the
actual sector numbers (but I think some formatters leave them as zero).

Which actually makes me really nervous - it implies that we've probably 
seen partitions 1&2 contain garbage there, and the problem is that if 
you'r etoo careful in checking, you will make a system unusable.

This is why it is so much nicer to be overly permissive ratehr than being 
a stickler for having all the values right.

And your random byte checks for power-of-2 make no sense. What are they
based on?

		Linus