Re: Yet another base64 patch

From: Kevin Smith <yarcs@qualitycode.com>
Date: Apr 18, 2005, 12:59 UTC
Message-ID: <4263AF41.1070806@qualitycode.com>
In-Reply-To: <426341FC.7090600@dwheeler.com>

David A. Wheeler wrote:

> Does anyone know of any other issues in how git data is stored that
> might cause problems for some situations?  Windows' case-insensitive/
> case-preserving model for NTFS and vfat32 seems to be enough
> (since the case is preserved) so that the format should work,

If git is retaining hex naming, and not moving to base64, then I don't think what I am about to say is relevant. However, if base64 file naming is still being considered, then vfat32 compatibility may be a concern (I'm not sure about NTFS). Although it is case-preserving, it actually considers both cases as being the same name. So AaA would overwrite aAa.

If I'm doing the math right, we would effectively be ignoring roughly one out of 6 base64 bits. This would reduce the collision avoidance capability of SHA-1 (on vfat32) from 160 bits to about 133 bits. Still strong, and probably acceptable, but worth noting.

I'll take this opportunity to support David's position that it would be fantastic if git could end up being valuable for a wide range of projects, rather than just the kernel. I also fully understand that the kernel is the primary target, but when there are opportunities to make the data structures more generally useful without causing problems for the kernel project, I hope they are taken.

Thanks,

Kevin