Re: [SLUG] Re: pseudo block device piping to smb or nfs -- MO = { CD-RW, DVD-RW, DVD+RW, etc... }

From: Eben King (eben1@tampabay.rr.com)
Date: Fri Sep 10 2004 - 14:12:32 EDT


On Fri, 10 Sep 2004, Bryan J. Smith wrote:

> On Fri, 2004-09-10 at 12:59, Eben King wrote:
>
> > Is there any error detection/correction,
>
> Of course not. That adds overhead, hence why DVD-RAM is SLLOOOOWWWW.
> The other option is to do a verify after write in software -- now that's
> even slower!

OK, how about an archiver with ECC? Enhanced tar? Checksum for each
file/block/MB?

> > or can I expect every full DVD+/-RW I write to start with 25 errors?
>
> ??? "Start" with 25 errors? Huh???

Well, some number of errors inherently (30-40 if 1E9b, 4-5 if 1E9B), PLUS
scratches, manufacturing defects, cosmic rays while reading, etc.

> The "average" of a device that has an error rate of 1 per billion would
> be 5 per 5 billion bytes. It doesn't necessarily mean you will hit it.

Sure. But the odds are you'll have _some_.

-- 
-eben    ebQenW1@EtaRmpTabYayU.rIr.OcoPm    home.tampabay.rr.com/hactar
TAURUS:  You will never find true happiness - what you gonna
do, cry about it?  The stars predict tomorrow you'll wake up,
do a bunch of stuff and then go back to sleep.  -- Weird Al

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