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Author Topic: Archival properties of unused Hard Drives  (Read 36482 times)
Gemmtech
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« Reply #20 on: January 22, 2011, 05:58:32 AM »
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No doubt about it you are right.  I know a couple people who lost everything in house fires and it's amazing that photographs are the items they miss most, just about everything else is replaceable. 
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knweiss
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« Reply #21 on: January 22, 2011, 11:00:21 AM »
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Modern drive heads are down to reading quantum levels, at this level you can't observe something without affecting it; you have to read and refesh what is there

https://www1.hitachigst.com/hdd/technolo/gmr/gmr.htm

To quote the article Chris mentioned: "So...in the interest of checking things out, simply reading every sector on a disk actually is preventative; if the controller within the disk detects any marginal data in either the servo tracks or the data bits recorded on the surface, the controller will automatically rewrite the data to the sector.". I.e. the refresh/rewrite is the exception and not the rule.

If each read operation would require a refresh reading from a hdisk couldn't be faster than writing (but it is).
« Last Edit: January 22, 2011, 11:28:47 AM by knweiss » Logged
John.Murray
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« Reply #22 on: January 23, 2011, 03:54:21 PM »
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If each read operation would require a refresh reading from a hdisk couldn't be faster than writing (but it is).

Actually, I'm the one that posted that link.  You are correct in that an explicit write does not take place unless an error is detected, in fact all modern drives have separate read and write heads.  What does take place is a refresh (via bias) of the magnetic domain in the area where the data is located - the exact method depends on the technology involved.  The hitachi/ibm paper is actually pretty dated - i remember reading a great description of more current technologies recently, I'll update this post with a better link, describing vertical recording methods as soon as i can locate it

regards - John
« Last Edit: January 23, 2011, 03:56:59 PM by John.Murray » Logged

andyptak
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« Reply #23 on: January 26, 2011, 03:45:37 PM »
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I'm a Windows guy - please, no comments! - obviously I can't use the Apple script. Does anybody now if defragging a drive might have the same effect and wake those pixels up every few months or so? The big question in my mind, I'm not a techie, so I don't know, is what action occurs during this process and is that action sufficient if the drive really doesn't need defragging? Thanks.
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DeeJay
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« Reply #24 on: January 27, 2011, 07:20:09 AM »
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Wondering also...

I am using a Sata Dock to backup to bare Sata drives. It's a very effective solution.

Wondering though, as each drive has a high powered magnet inside, is it OK to file the drives away next to each other? or will the magnet effect the data of the drive next to it?

Thanks,
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kikashi
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« Reply #25 on: January 28, 2011, 02:46:24 AM »
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I'm a Windows guy - please, no comments! - obviously I can't use the Apple script. Does anybody now if defragging a drive might have the same effect and wake those pixels up every few months or so? The big question in my mind, I'm not a techie, so I don't know, is what action occurs during this process and is that action sufficient if the drive really doesn't need defragging? Thanks.
I suspect not. A defragmentor starts by looking at the directories and the individual files' block lists. If they indicate that there's no, or no significant, fragmentation, the app won't do anything more and the vast bulk of the disk will remain unread. It's only if it has to move files around that it will look at the rest of the disk.

Jeremy
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NikoJorj
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« Reply #26 on: January 28, 2011, 04:00:18 AM »
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Wondering though, as each drive has a high powered magnet inside, is it OK to file the drives away next to each other?
Just thinking out loud, but in a computer, HDD are generally set very close to each other without much if any side effects known?
With a dock (a solution I'm considering too), I'd be extra cautious about anything getting in the HDD connectors (just as with a CF card).

Otherwise, magnetism is kinda "enclosed" in the HDD box, and shoudn't be a problem as long as you don't live in an electric power plant I'd think.
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Nicolas from Grenoble
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DeeJay
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« Reply #27 on: January 28, 2011, 06:38:24 AM »
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Thanks, yeah that's what I was thinking.

I would highly recommend the Sata Dock. It's been a really effective and practical backup plan. I have a Hazel Droplet, it automatically saves the files to two eSata docks for two backup copies. When the disks are full I label them, print the a copy of the finder out and file them away.

I also have time machine running for hourly backups of my working files.

Such a simple and effective solution and bare sata drives are really so cheap these days!
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DanOksnevadPhotography
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« Reply #28 on: October 08, 2013, 10:39:47 AM »
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Yikes! This makes me worry a bit about my archived backups (currently all external hard drives & some DVDs stored in a fireproof safe). Are many of you switching over to a cloud based backup system? If so, how does that work (thousands of GBs of data to upload)? Any recommendations on the best backup solution (physical or virtual)? I have thousands upon thousands of wedding photographs from the years of my photography work that I need to keep safe. Cheers!
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John.Murray
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« Reply #29 on: October 09, 2013, 11:47:13 AM »
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Most "fireproof" safes are rated for paper (ignition point 451f), make sure your safe is rated for media.  The safest thing to do is each drive to a fresh one.....
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mediumcool
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« Reply #30 on: October 21, 2013, 12:59:43 AM »
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And another black magic trick for dead drives: stick them in a freezer for an hour and it might wake up for long enough to be able to pull data off it. This is counter-intuitive given the above point, but I've read enough anecdotes of successes to have tried it myself - to no success.

I did this years back on an Ultra-SCSI drive on a Mac, and it workedGrin
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dreed
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« Reply #31 on: October 28, 2013, 09:07:38 AM »
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Just wondering if anyone knows how long an unused hard drive will last for? Googling the matter returns mixed results and certainly nothing definitive or seemingly reliable.

I'm wondering about my backups, and 2nd backups. I wonder how reliable it all is.

Well, nothing lasts forever ... I've recently turned on hard drives that have seen no power in almost 10 years with no problems.
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