From mboxrd@z Thu Jan 1 00:00:00 1970 From: Loic Dachary Subject: erasure code and coefficients Date: Sun, 29 Jun 2014 11:30:01 +0200 Message-ID: <53AFDC99.9010009@dachary.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="72C5iC4igcdRd2tTqvKCXngPuAC31StRE" Return-path: Received: from mail2.dachary.org ([91.121.57.175]:59825 "EHLO smtp.dmail.dachary.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752383AbaF2JaI (ORCPT ); Sun, 29 Jun 2014 05:30:08 -0400 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Andreas-Joachim Peters Cc: Ceph Development This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --72C5iC4igcdRd2tTqvKCXngPuAC31StRE Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi Andreas, In http://anrg.usc.edu/~maheswaran/Xorbas.pdf I get the idea of computing= local coding chunks the way it is implemented in https://github.com/ceph= /ceph/pull/1921 (i.e. delegating encoding / decoding to other plugins). H= owever, there are theoretical aspects of the paper that I do not understa= nd and I'm hoping you can shed some light on it. In particular, I don't k= now what "coefficients" are about. For instance in the context of Figure = 2 caption : "The main theoretical challenge is to choose the coeffi=0Ecie= nts c(i) to maximize the fault tolerance of the code." Would you recommend a paper to read to better understand this ? Also I'd = like to understand what "coefficients" mean in the context of jerasure or= if they do not apply. Thanks for you help :-) --=20 Lo=EFc Dachary, Artisan Logiciel Libre --72C5iC4igcdRd2tTqvKCXngPuAC31StRE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlOv3JkACgkQ8dLMyEl6F23VuACguhY2WUnUx7sdz3XO9Nas7CzW f70Anjp4eOznFVVjbbKULYoWWCJehR1R =vbh9 -----END PGP SIGNATURE----- --72C5iC4igcdRd2tTqvKCXngPuAC31StRE--