Is data on a write protected device safe forever?

[fauzan_22]

I have a sandisk cruzer blade 32 gb pen drive it has become write protected through a hardware or software fault and has been like that for sometime. I was wondering how long will it stay like this? as long as I keep it safe from any hardware damage how long can the data in pen drive be safe?

I'm not looking for any solutions to remove the write protection as I have tried a lot of different methods but to no avail and have accepted its current state. I was just curious to know how long can the data on it be safe.

 

[rhysiam]

Obviously it won't last forever. The value that gets thrown around a bit is "10 years", but I'm really not sure how scientific that value is.

Here's a longer explanation: all NAND cells (which is what data is stored in for all flash based storage including SSDs and USB flash drives) store data by trapping a particular charge (voltage state) in each cell. Reading the data involves checking the voltage state. Over time (in most circumstances, we're talking several years at least), the voltage state will drift slightly. That's because the cell isn't able to perfectly isolate the charge. How quickly that happens and whether it becomes a problem depends on a variety of factors including the quality of the NAND itself, the temperature at which the data was written, the temperature at which the device was stored, the error correcting algorithms used by the flash controller and finally - this is the particularly important one - how many times each NAND cell has been written to previously. The latter happens because flash memory does wear out over time, meaning that as it's written to (not read from - just written to) time and again it gradually loses it's ability to isolate it's stored charge/voltage state.

If you're interested in more, Anandtech did a pretty good write up on this a while back: http://www.anandtech.com/show/9248/the-truth-about-ssd-data-retention
The article relates to SSDs specifically, and an outlandish claim that was being used in click-bait articles a couple of years back. But the basic principles are the same.

All the above is basically a long way of saying... no one can really tell you how long it will last. It's extremely likely that you could put in a draw for a year and all your data would be perfectly readable. It's pretty likely that if you tried to read from it after it had been sat in a drawer for 100 years you'd have serious problems. How long between 1 and 100 years will the data last... I don't think anyone can really say.

General principle though: if the data is important, make sure you have a reliable backup in place AND make sure you have a system in place which checks whether the backup is actually working successfully.

 

[fauzan_22]

Thanks for the thorough explanation. But what if the data is not being written to the device but only being read from and the device has become malfunctioned to become write protected won't it change things a bit? Has there been any articles on this particular scenario.

 

[rhysiam]

Whether it's write protected or not is irrelevant for data retention.

When you say it's "malfunctioned" - we have no idea what's gone wrong, so I can't really speculate whether that will affect the life of the drive or its data.

If you're reading from the data regularly that **could** help extend it's life. Because of the issues that can arise from flash memory most controllers, even (I believe - but I'm not 100% sure) most USB flash drives, utilise some form of error correction, such that occasional errors in reading data can be overcome and the data is not lost. Certainly SSD controllers in that situation will then re-write the data to fresh NAND cells and potentially (if required) mark failed cells as bad and cease to use them. I suspect (but I don't know for sure) that most decent quality USB drives will do a similar thing. So in your situation that would mean that if the data on some cells started to fail, these errors would be overcome, and hopefully data salvaged and moved to fresh cells. Whether your drive can still do that in "read only" mode I have no idea.

I'm really not quite sure what answer you're looking for here. No one is going to be able to accurately tell you when that flash drive will fail. Like I said in my previous post, if the data is important, make sure it's backed up somewhere. That applies to ALL data on ANY storage medium, but especially to a USB flash drive which are notoriously unreliable, and doubly so for one like yours which has had some sort of error and is no longer operating as designed.

Either the data matters to you, in which case back it up somewhere else. Or it doesn't, in which case who cares when the drive fails.

 

[fauzan_22]

The most likely reason the pen drive got write protected was maybe because of an antuvirus software which had "usb write protect" option in it but I'm not cpmpletely sure as i tried disabling it but that didnt changed the state of the pen drive.

The data isn't really important but I still use it regularly as it became write protected at a time when it it had useful applications and files on it which I have copies of.

Thanks again rhysiam.

 

[elbert]

Electrical charge disapates over time but I dont suggest waiting that long. Here is some steps to try to correct the issue.
1. Plunge this drive or memory card to a computer.
2. Click “Start” on the taskbar to open “Run” and type “regedit”.
3. Hit “HKEY_LOCAL_MACHINE” to expand “System”.
4. Find “Current Control Set” in “System” list to click “Control”.
5. Check whether there is a key named “Storage Device Policies” to change the digit in the “DWORD value” box into "0" and press “OK”.
But, if you cannot find the key named “Storage Device Policies”, you are supposed to create a one: right click “Control” to create a new key and name it as “Storage Device Policies”=> right click this new key to open “DWORD Value” and name it as “write protect”=> Double click it to change number.

 

[fauzan_22]

Thanks for the suggestion Elbert but I have tried that and many other methods to remove the write protection but to no avail.