From mboxrd@z Thu Jan 1 00:00:00 1970 From: ron@ronnatalie.com (Ron Natalie) Date: Thu, 11 May 2017 19:48:27 -0400 Subject: [TUHS] The evolution of Unix facilities and architecture In-Reply-To: References: <20170511140729.2262B18C09A@mercury.lcs.mit.edu> <013b01d2ca96$6901b370$3b051a50$@ronnatalie.com> <20170511222547.GJ4341@mcvoy.com> Message-ID: <017001d2cab1$16bcf4b0$4436de10$@ronnatalie.com> Ordered writes go back to the original BSD fast file system, no? I seem to recall that when we switched from our V6/V7 disks, the filesystem got a lot more stable in crashes. -----Original Message----- From: TUHS [mailto:tuhs-bounces@minnie.tuhs.org] On Behalf Of Dave Horsfall Sent: Thursday, May 11, 2017 7:47 PM To: The Eunuchs Hysterical Society Subject: Re: [TUHS] The evolution of Unix facilities and architecture On Thu, 11 May 2017, Larry McVoy wrote: [...] > Try the same thing with Linux. The file system will come back, > starting with, I believe, ext2. That's a journalled FS, isn't it? In which case the transactions get replayed. > My belief is that Linux orders writes such that while you may lose > data (as in, a process created a file, the OS said it was OK, but that > file will not be in the file system after a crash), but the rest of > the file system will be consistent. I think it's as if you powered > off the machine a few seconds earlier than you actually did, some > stuff is in flight and until they can write stuff out in the proper > order you may lose data on a hard reset. And FreeBSD (at least) has been doing ordered writes for quite some time. -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."