From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Lanza Subject: Re: CONFIG_VFAT_FS_DUALNAMES regressions Date: Tue, 21 Jul 2009 15:38:08 -0400 Message-ID: <4bbed3f70907211238t769d610aj24fc7d5dd48d99a3@mail.gmail.com> References: <19013.8005.541836.436991@samba.org> <20090708163736.0f98e7e0@lxorguk.ukuu.org.uk> <1247069202.4159.212.camel@mulgrave.site> <20090708171848.21633768@lxorguk.ukuu.org.uk> <873a96a23x.fsf@devron.myhome.or.jp> <87hbxhwv0j.fsf@devron.myhome.or.jp> <19045.14307.658887.752950@samba.org> <4A65875D.7030902@panasas.com> <19045.48361.502946.399660@samba.org> <4bbed3f70907210806v14690311wbd579acae44099a9@mail.gmail.com> Reply-To: john.lanza@linux.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Boaz Harrosh , Linux Kernel Mailing List , Alan Cox , James Bottomley , Martin Steigerwald , Jan Engelhardt , Theodore Tso , Rusty Russell , Pavel Machek , OGAWA Hirofumi , linux-fsdevel@vger.kernel.org, Dave Kleikamp , corbet@lwn.net, jcm@jonmasters.org, torvalds@linux-foundation.org To: tridge@samba.org Return-path: Received: from mail-yx0-f202.google.com ([209.85.210.202]:39211 "EHLO mail-yx0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755588AbZGUTiL convert rfc822-to-8bit (ORCPT ); Tue, 21 Jul 2009 15:38:11 -0400 In-Reply-To: <4bbed3f70907210806v14690311wbd579acae44099a9@mail.gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Resending in plain text....... On Tue, Jul 21, 2009 at 11:06 AM, John Lanza wrote: > If I understand the proposal (which I think I do), Tridge is correct. > If a patent prohibits a system from performing steps "A" and "B", > simply separating the steps into separate modules, or utilities, won'= t > avoid infringement. > > I'm happy to answer specific questions, but it might be best to do > that separately from lkml. > > johnl > > On Tue, Jul 21, 2009 at 9:04 AM, wrote: >> Hi Boaz, >> >> =A0> I guess you tried putting a zero at first char and it breaks ev= erybody? >> >> It works with some devices, but with many it doesn't. A space follow= ed >> by a nul works with quite a lot of devices, but not enough (the last >> patch used a space followed by a nul). >> >> I went to a large electronics store and told them I wanted to buy >> devices that didn't work with my computer. They were very helpful, a= nd >> as a result I was able to test a lot of devices. That is what led to >> the design of this patch (plus the feedback from people like Jan and >> his IOneIt MP3 player). >> >> =A0> I guess (35^6)*8*7 is not that bad >> >> yes, but luckily For the WinXP bluescreen the probability of the cra= sh >> is actually much lower than that figure would give. With the same >> modelling assumptions of WinXP memory slots for 8.3 entries that Pau= l >> used for the last patch, it comes out as less than a 1 in 10k chance >> for a full directory (ie. 32767 long filenames). For 100 files in a >> directory it is around 1 chance in 10^11. I'm sure Paul will do the >> full expansion and modelling if anyone wants more precise numbers. >> >> For the chkdsk rename, the probability is much easier to calculate a= s >> it is just the usual birthday expansion (see wikipedia for simple >> formula for that). That is what gives 0.5% for 32767 files in a >> directory, and 4.8x10^-8 for for 100 files. >> >> Basically it won't happen very often. In each case the probability i= s >> rougly 75x less than it was for the last patch. >> >> =A0> What if we had a user mode utility that does these short-names >> =A0> renames that a user can optionally run after umount? since it >> =A0> only writes the (random) short-names it's also safe. >> >> While I will defer to John Lanza if you want a more complete legal >> view on this, I think it is likely that separating the steps of the >> patent between programs within one system is not a safe enough legal >> strategy to be used. >> >> Please do keep thinking about it though. There could well be some >> simple combination which is legally safe and also technically >> completely satisfactory. If you think you have hit on a winner, you >> may wish to discuss it with John Lanza in private first though, so i= t >> can be fine tuned before being presented publicly. >> >> Cheers, Tridge >> > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html