From 91ad1e7f24801d669923dbee157e73254749e79f Mon Sep 17 00:00:00 2001 From: Andrea Mazzoleni Date: Sun, 15 Sep 2013 16:10:58 +0200 Subject: [PATCH] More comment about Quad parity. --- raid.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/raid.c b/raid.c index 9f10c4f7..bcbf9c8e 100644 --- a/raid.c +++ b/raid.c @@ -836,14 +836,14 @@ void raid_gen(unsigned level, unsigned char** buffer, unsigned diskmax, unsigned * Using different parity generators like "1,7,53,139" it's possible to * make it working for up to 33 disks. But no more. * - * A general method working for Quad Parity and more, can be found in [3] - * and corrected in [4], but with a slower computational performance, - * because the coefficients of the equations are arbitrarely chosen, - * and not derived from parity generators. + * A general method working for Quad Parity and more, is to use a + * Vondermonde matrix [3] and [4] or a Cauchy matrix [5], but resulting + * with a slower computational performance, because the coefficients of + * the equations are arbitrarely chosen, and not derived from parity generators. * This means that you need to use multiplication tables to implement the * syndrome computation, instead of the fast approach described in [1]. * Note anyway, that there is also a way to implement multiplication tables - * in a very fast way with SSE instructions [5]. + * in a very fast way with SSE instructions [6]. * * In details, Triple Parity is implemented for n disks Di, computing * the syndromes P,Q,R with: @@ -894,11 +894,12 @@ void raid_gen(unsigned level, unsigned char** buffer, unsigned diskmax, unsigned * of equations with a different solution. * * References: - * [1] H. Peter Anvin, "The mathematics of RAID-6", 2004 - * [2] David Brown, "Multiple-parity RAID", 2011 - * [3] James S. Plank, "A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems", 1999 - * [4] James S. Plank, Ying Ding, "Note: Correction to the 1997 Tutorial on Reed-Solomon Coding", 2003 - * [5] James S. Plank, "Screaming Fast Galois Field Arithmetic Using Intel SIMD Instructions", 2013 + * [1] Anvin, "The mathematics of RAID-6", 2004 + * [2] Brown, "Multiple-parity RAID", 2011 + * [3] Plank, "A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems", 1999 + * [4] Plank, Ying Ding, "Note: Correction to the 1997 Tutorial on Reed-Solomon Coding", 2003 + * [5] Blömer, "An XOR-Based Erasure-Resilient Coding Scheme", 1995 + * [6] Plank, "Screaming Fast Galois Field Arithmetic Using Intel SIMD Instructions", 2013 */ /**