On 9-Nov-07, at 3:23 PM, Scott Laird wrote:

> Most video formats are designed to handle errors--they'll drop a frame
> or two, but they'll resync quickly.  So, depending on the size of the
> error, there may be a visible glitch, but it'll keep working.
>
> Interestingly enough, this applies to a lot of MPEG-derived formats as
> well, like MP3.  I had a couple bad copies of MP3s that I tried to
> listen to on my computer a few weeks ago (podcasts copied via
> bluetooth off of my phone, apparently with no error checking), and it
> made the story hard to follow when a few seconds would disappear out
> of the middle, but it didn't destroy the file.

Well that's nice. How about your database, your source code, your ZIP  
file, your encrypted file, ...

--T

>
>
> Scott
>
> On 11/9/07, David Dyer-Bennet <[EMAIL PROTECTED]> wrote:
>> can you guess? wrote:
>>
>>> CERN was using relatively cheap disks and found that they were  
>>> more than adequate (at least for any normal consumer use) without  
>>> that additional level of protection:  the incidence of errors,  
>>> even including the firmware errors which presumably would not  
>>> have occurred in a normal consumer installation lacking hardware  
>>> RAID, was on the order of 1 per TB - and given that it's really,  
>>> really difficult for a consumer to come anywhere near that much  
>>> data without most of it being video files (which just laugh and  
>>> keep playing when they discover small errors) that's pretty much  
>>> tantamount to saying that consumers would encounter no  
>>> *noticeable* errors at all.
>>>
>>
>> I haven't played with bit errors in video.  A bit error in a JPEG
>> generally corrupts everything after that point.  And it's pretty easy
>> for people to have a TB or so of image files of various sorts.
>> Furthermore, I'm interested in archiving those for at least the  
>> rest of
>> my life.
>>
>> Because I'm in touch with a number of professional photographers, who
>> have far more pictures than I do, I think of 1TB as a level a lot of
>> people are using in a non-IT context, with no professional sysadmin
>> involved in maintaining or designing their storage schemes.
>>
>> I think all of these are good reasons why people *do* care about  
>> errors
>> at the levels you mention.
>>
>> One of my photographer friends found a bad cable in one of his  
>> computers
>> that was upping his error rate by an order of magnitude (to 10^-13 I
>> think).  Having ZFS would have made this less dangerous, and  
>> detected it
>> more quickly.
>>
>> Generally, I think you underestimate the amount of data some people
>> have, and how much they care about it.  I can't imagine this will
>> decrease significantly over the next decade, either.
>>
>> --
>> David Dyer-Bennet, [EMAIL PROTECTED]; http://dd-b.net/
>> Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/
>> Photos: http://dd-b.net/photography/gallery/
>> Dragaera: http://dragaera.info
>>
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