Subject: Re: mkisofs file size limit
To: None <>
From: Frederick Bruckman <>
List: tech-pkg
Date: 03/13/2005 01:37:31
In article <>,
	Todd Vierling <> writes:
> On Wed, 9 Mar 2005, Dieter Baron wrote:
>> : Is there any way I can get round the file size limit of 0x7FFFFFFF?
>> : What determines this limit?
>>   It's the largest size that can be represented as a signed 32 bit
>> value, and some people seem to think the size field in ISO 9660 file
>> systems is a signed value; playing it save, I guess.
> Many ISO9660 client implementations still use a signed 32-bit int, so 2GB is
> indeed the practical limit for a file in such a filesystem.  There's a
> reason that DVD video discs limit VOBs to 1GB each; the splitting was deemed
> necessary to keep them well within the ISO9660 safety limits.

Make that 2GB - 1.  2GB would be interpreted as negative by
implementations that represent file sizes with signed 32-bit ints,
so 1GB is indeed the largest "round number" that would fit.

> Above 2GB, UDF is the only truly compatible choice, and ISO9660 is out the
> window altogether.

I've composed a patch to write files of arbitrary size (greater than 4GB)
using multiple extents, conditionally on giving "-iso-level 3".  The only
guaranteed method to extract them is using "isoinfo" as patched by the patch,
although my DVD Video (hardware) player happens to be able to play them.
Anybody interested?