From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jakub Narebski <jnareb@gmail.com>
Subject: Re: GSoC - Designing a faster index format
Date: Thu, 22 Mar 2012 17:46:09 -0700 (PDT)
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Cc: Nguyen Thai Ngoc Duy <pclouds@gmail.com>,
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To: elton sky <eltonsky9404@gmail.com>
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elton sky <eltonsky9404@gmail.com> writes:

> Got a few questions:
> 
> 1. index is used for building next commit, so it should only include
> files created/modified/deleted. But I see it has all entries for
> current working dir. why?

Because git is snapshot based, not changeset based.  Ecah commit
stores state of repository in the form of 'tree' object, which is
build out of index.
 
Also index stores extra information, like mtime, about all files
to make operations faster (skip unchanged files).  The index was
originally at the very beginning named dircache.

[...]
-- 
Jakub Narebski