From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Sat, 08 Jan 2011 02:17:57 GMT
Subject: Re: Resumable clone/Gittorrent (again)
Message-ID: <AANLkTimgn2_BWYjbGKbGoeGJ=erKundX4umfy=s16dB1@mail.gmail.com>
In-Reply-To: <AANLkTikKn1+2OX1KPy+9US_yX=E6+CiaCTTB6yqnAWwW@mail.gmail.com>

On Fri, Jan 7, 2011 at 10:59 PM, Luke Kenneth Casson Leighton
<luke.leighton@gmail.com> wrote:
>  bottom line: my take on this is (sorry to say, nguyen) that i don't
> believe bittorrent "pieces" map well to the chains concept, unless the
> chains are perfectly fixed identical sizes [which they could well be?
> am i mistaken about this?]

there are a few characteristics of bittorrent pieces that i see:
verifiable, resumable, uniquely identifiable across peers and
reasonbly small in count.

The fixed size helps peers uniquely identify any pieces by splitting
the whole transfer equally and indexing them in 1-dimension. It's a
rule to help identify pieces, not the only valid rule. In git, given a
commit SHA-1 we can identify any parts (or "pieces") that are
reachable from that commit using rev-list syntax. Therefore the
"identifiable" characteristics still holds even we don't split in
fixed size pieces.
-- 
Duy