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Scenario

Currently, my various data files (the files I create myself and are thus irreplaceable), are spread out over several directories on a couple of system. I want to consolidate them all into one place. I want to put them all onto a flash-drive (or even better a memory-card since it goes inside a laptop instead of sticking out of the side). Since they would all be in a single, small location, it makes them easier to back up as well as always available on any system I am using (which is good because then I always have something to work on).

Problem

My only concern is the nature of flash-memory. I’ve read countless articles and opinions on how flash-memory is reliable, is not reliable, does wear out, won’t wear out for most people, and so on. Unfortunately none of it is conclusive (certainly not for a broad range of devices).

Work-around

To accommodate the nature of flash-memory, I have decided to make “regular” back-ups of the drive (though I am up to 5.5GB already, so I can only keep a couple at a time).

Question

This leaves one potentially major issue: Corruption/notification of failure.

I can accept having to rely on making backups for peace of mind, but what I am dreading is that the drive will accept a write but then later on, when I try to read it, it turns out to be garbled.

So what I want to know is if there is a warning or error when a flash-drive/memory-card fails. Obviously it will attempt to remap dead cells as much as possible, but is corruption a real concern? Will users be told that the drive could not be written so that they can stop using it, or could we find out only after continuing to use it for a while a discover corrupted files—that may even make it into the backup! (Ideally, I’d like to know if there is a warning in general, but at least in Windows.)

Research

(Finding an answer to this question is surprisingly difficult due to the nature of the query terms. The last one finds information about the delayed write failure message, but that goes for any removable drive and is not specific to flash-memory device. There is a similar question here that asks what happens when a flash-drive fails, but it is more along the lines of remapping cells instead of error-notification which is what I am asking; I want to know what happens after wear-leveling fails.)

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In my experience with USB sticks, SD cards of various hues and even SSDs, when they do fail (and I'm not talking about physical damage) they do so catastrophically without any real warning whatsoever (YMMV of course, so see my last sentence). There they are, humming along just fine, and then one fine day poof! :( No real warning as with traditional drives, and so I've given up trusting them wih long-term storage of important data. BTW, do you really think a question like this about how hardware might behave while failing will have a one-size-fits-all answer? –  Karan Jun 10 '13 at 22:27
    
@Karan, I would think/hope that when a flash-memory device cannot write, it fails in some predictable way like by having the controller return an error in response to the write query. This error would then be returned to the OS so that the software can catch and handle it elegantly. So yes, I do think it can/**should** have a one-size-fits-all answer (at least if hardware manufacturers know what the heck they are doing). My concern is that they don’t and like you said, they fail silently and unpredictably (like being back in the digital stone-age before exception-handling was invented). –  Synetech Jun 11 '13 at 2:21
    
Even if that exception-handling were in place, when it comes to failure who's to say there's any guarantee the handler will have an opportunity to kick in before the failure occurs? Some people might be "lucky" enough to see a warning, others might not. Anyway so far unfortunately it seems I have only been in the latter category. –  Karan Jun 11 '13 at 2:24
    
Even if that exception-handling were in place, when it comes to failure who's to say there's any guarantee the handler will have an opportunity to kick in before the failure occurs? That could be said of any and every device. That hasn’t stopped other devices like HDDs or NICs and such from reporting hardware errors to the OS. There’s nothing unique about flash devices in this respect. Surely the drive’s firmware is able to detect an error and report it instead of simply exploding; it’s not exactly rocket-surgery. –  Synetech Jun 11 '13 at 3:43
    
I've had HDDs that failed with no prior warning too. All I'm saying is, no guarantee of a warning when it comes to hardware failure. Whether the device was built so that it would attempt to warn is a different matter altogether. I would assume that is the case in this day and age. Anyway, I'll see if there's any firmware literature to be found on the subject. –  Karan Jun 11 '13 at 3:45
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