Re: What to do about the 2TB limit on HDIO_GETGEO ?

From: Mark Lord
Date: Tue Mar 25 2008 - 09:34:39 EST


Linus Torvalds wrote:

On Mon, 24 Mar 2008, Mark Lord wrote:
The return value uses "unsigned long",
which on a 32-bit system limits drive offsets to 2TB.

One relevant question is: does anybody seriously care about the combination of "32 bit" and "huge modern drives" any more?

Sure, we can add a 64-bit version that ends up being used only on 32-bit systems, but quite frankly, I think the solution here is to just ignore the issue and see if anybody really even cares.

Because quite frankly, the kind of people who buy modern 2TB drives generally don't then couple them to CPU's that are five+ years old.
..

Yeah. Except Dell will undoubtedly have them in desktops
within 2 years, and tons of people (myself included) still use
32-bit (K)Ubuntu on our systems, simply for the better binary compatibility that it is perceived to give with things like
browser plugins and stuff.

Using sysfs interfaces might be a good alternative,
if they were easier to use, but drives are not directly
accessible there using the dev_t value from stat(2).

Instead, software has to search everything inside /sys/block/
looking for a "dev" file whose contents match,
rather than just trying to access something like this:

/sys/block/8:1/start
or
/sys/block/majors/8/minors/1/start

Or any one of a number of similar ways to arrange it.

Cheers
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