Date: Fri, 9 Jun 2006 12:15:33 +0930 From: "Daniel O'Connor" <doconnor@gsoft.com.au> To: freebsd-current@freebsd.org Cc: Pawel Jakub Dawidek <pjd@freebsd.org> Subject: Re: Data authentication for geli(8) committed to HEAD. Message-ID: <200606091215.41787.doconnor@gsoft.com.au> In-Reply-To: <20060608174113.GC1075@roadrunner.q.local> References: <20060608132048.GD86198@garage.freebsd.pl> <20060608174113.GC1075@roadrunner.q.local>
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[-- Attachment #1 --] On Friday 09 June 2006 03:11, Ulrich Spoerlein wrote: > I have an external HDD that I initially attached via Firewire, but I've > since switched to USB, as our firewire subsystem is less than rock Interesting. I find the reverse :) Then again I started using Firewire in 4.x where USB2.0 didn't exist and the USB 1 code was kind of dodgy. > The question really is, are 512 byte disk writes considered to be some > kind of "atomic" as it is the smallest disk block size? What does the > ATA subsystem do with writes of 4096? Are they completed atomically too, > or not? I think that in reality with a modern high capacity disk you don't get atomic writes at all because they all re-write whole tracks. Yes this violates the assumption soft updates makes, I believe the only way around it is to buy SCSI drives (not because they're SCSI per se, but because they're smaller capacity so they don't do this) -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (FreeBSD) iD8DBQBEiODV5ZPcIHs/zowRAvnRAKCdbFsjpBtt0pzvmA2F6VZyQb7ElQCcDk6v K+pSiJ69ThtEBj5EcWABh9U= =KYEN -----END PGP SIGNATURE-----
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