On 8/4/07, Dave Dillow <dave@xxxxxxxxxxxxxx> wrote: > On Fri, 2007-08-03 at 09:04 +0400, Manu Abraham wrote: > > On 7/31/07, Evgeniy Polyakov <johnpol@xxxxxxxxxxx> wrote: > > > > > TODO list currently includes following main items: > > > * redundancy algorithm (drop me a request of your own, but it is highly > > > unlikley that Reed-Solomon based will ever be used - it is too slow > > > for distributed RAID, I consider WEAVER codes) > > > > > > LDPC codes[1][2] have been replacing Turbo code[3] with regards to > > communication links and we have been seeing that transition. (maybe > > helpful, came to mind seeing the mention of Turbo code) Don't know how > > weaver compares to LDPC, though found some comparisons [4][5] But > > looking at fault tolerance figures, i guess Weaver is much better. > > > > [1] http://www.ldpc-codes.com/ > > [2] http://portal.acm.org/citation.cfm?id=1240497 > > [3] http://en.wikipedia.org/wiki/Turbo_code > > [4] http://domino.research.ibm.com/library/cyberdig.nsf/papers/BD559022A190D41C85257212006CEC11/$File/rj10391.pdf > > [5] http://hplabs.hp.com/personal/Jay_Wylie/publications/wylie_dsn2007.pdf > > Searching Google for Dr. Plank's work at the University of TN turns up > some analysis of using LDPC codes in storage systems. > > http://www.google.com/search?hl=en&q=plank+ldpc&btnG=Google+Search > > Patents are an issue to watch out for around the use of Tornado/Raptor > codes. I've not researched it, but I believe there be dragons there. > We don't use the code in the driver straight away [2] (in the case that i mentioned), since that happens in the hardware (demodulator chip) [1], but we have an interface for selecting the code-rate [2] (LDPC/BCH) for DVB-S2 and the new papers for DVB-T2 looks geared that the base decision is to use LDPC. Though i now see a patent application for it [3]. Not sure whether it is a registered patent, i am under an agreement of Non-Disclosure with STM. Will ask the relevant person there, whether they have it registered. (Most probably they may have it registered). There are a few people from STM on LK, if not they can possibly confirm whether the patent is regsitered or not. [1] http://www2.dac.com/data2/42nd/42acceptedpapers.nsf/0c4c09c6ffa905c487256b7b007afb72/998f93e4b29e99fa87256fc400714617/$FILE/33_1.pdf [2] http://linuxtv.org/hg/~manu/stb0899-c5/file/760cb230695c/linux/include/linux/dvb/frontend.h [3] http://www.freepatentsonline.com/20060206779.html http://www.freepatentsonline.com/20060206778.html - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
