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Nightmare - External hard drive crashes to floor

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saint:
You put entirely too much into my reply :)

SavannahLion:
MonMotha, I'm a little confused at your post there. At first you write about individual components, then it seems like you're talking about integrated devices.

From an archival standpoint, the fact an SLC or any other component lasts 10 years across a temperature range matters jack when another component on the device lasts only say.... three to five. You're going to end up going with the smaller value and paying out the ass to recover if that ever happens.

(I would kill to find out where my 16/10/40A is. I'm stuck using this Pioneer DVR-116D in the meantime)

MonMotha:

--- Quote from: SavannahLion on February 23, 2010, 01:17:57 am ---MonMotha, I'm a little confused at your post there. At first you write about individual components, then it seems like you're talking about integrated devices.

From an archival standpoint, the fact an SLC or any other component lasts 10 years across a temperature range matters jack when another component on the device lasts only say.... three to five. You're going to end up going with the smaller value and paying out the ass to recover if that ever happens.

(I would kill to find out where my 16/10/40A is. I'm stuck using this Pioneer DVR-116D in the meantime)

--- End quote ---

Data on discrete components is much, much easier to obtain since most device manufacturers just plain don't give it out (or sometimes even know it!) or will only give a MTTF/MTBF which isn't a particularly useful number.  Device integrators don't seem to take "product specifications" as seriously as semiconductor makers.  You have to pay a LOT more than normal consumer products to get warranties that cover data loss due to product failure.  That's just the way the industry has gone.  However, there are some integrators that do publish specs and who are known for consistently meeting their specs (and often exceeding them) while others can frequently fail to deliver.  Caveat emptor.  You do often get what you pay for.

One other thing to consider is that there are a LOT of flash media integrators but not many flash semiconductor makers (at this point, there's only 2 or maybe 3).  Therefore it's easier to speak generally about the bare semiconductors than the integrated devices.

Integrated device lifetimes DO vary, and that's what you care about in the end.  The cheap crap sometimes barely makes it a year.  Mostly, this is due to terrible firmware (bad block replacement or lack thereof, bad wear leveling or lack thereof, etc.) but sometimes also cheap components or improper design (bad power is a common issue).  If you intend on archiving on flash media, make sure you get something that doesn't suck.  Sandisk has some products that they give real specs on (5 years minimum lifetime non-operating from -55C to +95C or 43,800 power-on hours is a spec I just pulled for one of their SSD products, but at the prices they sell them normally, there is no warranty to that effect), but generally only on their OEM products.  Sandisk does have a reputation for meeting their specs, at least.  I also note that their standard SD cards include a 5 year warranty.  While they may not be on the hook for data loss, they would have to deal with the cost of replacement and all the logistics of failures, so I'd guess they're pretty confident that the devices will last at least that long.

When people write up warranties and such, they tend to be rather conservative.  It's expensive to pay out on a warranty (it generally costs a lot more than the cost of the product).

As another anecdotal data point, I do have a few CF cards from ~2003-2004 that still seem to read fine, but it's been a couple years since I tried them.  I did have one really cheap card that died about a year after I got it, but it wasn't due to flash retention issues.  It just completely stopped working.  A failure nonetheless, but again, it was a real cheapie.  I think all my Sandisk and Kingston branded media still works.

As an unusually topical example, there are lots of arcade games floating around that store their data on flash memory.  In many cases, a standard PCMCIA or CF card is used.  Compared to everything else that goes wrong in these things, the flash devices seem to be very, very reliable.  These things sit around for years powered up and operating every day.  Flash memory is EVERYWHERE.  It's been used to store firmware on many production devices for the past 10-15 years.  On the whole, it sure seems pretty reliable.

My experience is mostly with discrete devices as that's what I'm normally specifying when doing designs.  Retention and temp range is definitely something I look at.  I have been known to request additional characterization data from vendors, and they're generally happy to provide.  If you do plan on archiving using flash media (and I can't say I wholly recommend it), you should get a device from a reputable integrator, and, of course, you should always have more than one copy.  Overall device failures tend to be sudden and catastrophic due to some outside influence or design flaw, while bitrot due to floating gate charge degradation on flash happens over time at a fairly steady pace (you just don't notice it because, as long as the sense amp can still figure things out, a nice, clean 1 or 0 comes out).  Multiple copies guards especially well against the former, while it doesn't really help much with the latter.  Of course, multiple copies on different media types is even better.

Nothing is immune to failure.  Unexpected stuff happens.  That's why you keep multiple copies.  Heck, that's why you're keeping backups in the first place.  If you've got reasonable assurance that something will last 5-10 years with the potential for it to last several dozen more, I'd say that's a pretty good medium term storage solution.

Grasshopper:

--- Quote from: shmokes on February 21, 2010, 07:10:44 pm ---One thing I intend to do relatively soon, ie when I have a real job and can afford it, is start backing up to an online location for example with Amazon's S3 cloud storage offering.  I've never used it but Microsoft offers 25 GB of free cloud storage with Windows Live SkyDrive.  It requires a LiveID, but I'm pretty sure that by now everyone already has one.

As for photos, there's really no excuse to lose digital photos.  How many unlimited free services do you need before you get your photos backed up online?  Flickr, Picasa, Shutterfly, Photobucket . . . even Facebook.  Apps exist for all of these to automate the process so you can just mass upload your photos.  Get.  It.  Done.

--- End quote ---

Personally, I think the whole cloud computing idea has been a bit overhyped. It requires a degree of trust in large faceless corporations that I simply don't have.

Online backup is fine as long as it's being done in addition to local backup, and the data being backed up is either of a non-confidential nature, or strongly encrypted. But if those conditions are not met then I wouldn't touch it with a bargepole.

The free services are the worst. They can (and sometimes do) pull the plug at any time without warning and you have absolutely no redress. Just look at Geocities for example. Even the paid for services give a false sense of security. Sure, you can sue the company if they lose your data but if they go bust you're still screwed. And even if you can sue them that doesn't actually get your data back. This might sound paranoid but events of the past year have shown us that even large household names can go bust overnight without warning.

There's also the issue of data security. Even if the company is well known, there's so much outsourcing and outshoring going on these days that you can never be really sure who you're dealing with.

shmokes:
But as far as free services are concerned I'm mainly talking about backing up photos.  And by backing up, I mean you have a local copy, and your backup is uploaded to your Flickr or Picassa account.  Sure those companies could go belly up (Picassa is Google :)), but the chances that the company happens to go belly up at exactly the same time that your house burns down or you accidentally drop your computer in a tub of water are not very high.  But even for other data, for example backing up to Microsoft's SkyDrive . . . there are definitely concerns and caveats, but no matter what you have to work within your means.  There is ALWAYS a better backup option.  ALWAYS.  ALWAYS.  ALWAYS.  But the better solution may not be feasible, whether because of finances, technical capabilities or motivation/discipline.  You have to ask yourself, what can I do, and what am I willing to do.  Then see what options correspond with the answers to those questions.  For some people the free services are very likely the best/only realistic option.

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