Are there limited *read* cycles on flash memory as well?

I'm just wondering, I know there are limited number of write cycles for flash memory, but are there limited read cycles on flash memory as well? I'm thinking along the lines of thumb drives, but this applies to all flash memory in general.

 

There aren't any read cycle limits as far as I know, but the data can get lost over time, due to electrons leaking from the floating gates. But usually this will take years. When exposed to heat this process can speed up a bit.

 

I still have a 256mb flash drive that gets used for school work...


its more than a few years old...

 

Well, the leaking only affects the data if it's just on the chip for a long time, 10 years and more I guess.

So if you just keep a stick without writing to it for about 10 years or more, chances are that the data gets corrupted. But when you write new data to the chip, the new data won't be affected by how long other, older data is already on it, it has it's own "countdown". The new data only starts to leak while the old already had a lot time to do so.

 

On a modern SSD, wear leveling will move even static data around on the drive, so as long as it's used once every few years, data loss should never be an issue. On a flash drive, I suppose it's possible, but I've been able to get data off drives that have been sitting in boxes for several years.

Reading flash cells does not cause wear.

 

Thanks for the replies.

That's what I was talking about, thanks.

 

Reading flash does cause problems - it's called read disturb and basically, the more we read the data the greater the chances are for reading it back wrong.

Nothing comes for free.

See:
SSD NAND Endurance: Intel Communities

 

Rain on my parade why don't you. I'm thinking along the lines of USB thumb drives, not SSDs. I hope they will last me.

 

I hope they last too.

I have seen spontaneous death syndrome on flash drives though. They work until they don't (like anything else).

When you also consider that SSD's have exponentially higher quality nand/controllers, I hope you're not considering storing anything important on them (without also being on at least one/two other devices (one being a dependable HDD, ).

 

As a matter of fact, yes, that's exactly what I want to do. I want to move away from optical storage to store my personal data. There are a few thumb drives I have in mind, all have write-protect switches. I have no desire for an external hdd.

 

Unless you'll be using (many) different USB keys with a variety of (hard to verify...) different tech inside - to backup the same data - I would not be advising anyone of this route.

How much data are we talking about here?

You may not have a desire for an external HDD (I'd recommend at least two, that you rotate periodically) - but if you value your data's accessibility and reliability - then two or more HDD's (copies of each other...) are the most reliable route right now/still.

Good luck.

 

External hard drives are out of the question. Period. Thumb drives are small, and can be easily concealed, as well as the data protected by the write-protect switch. I plan on buying two identical thumb drives for backup. Right now, I have about 22GB of data. A 32GB drive will be fine, and I'll have a backup in case the first fails. Atleast this is my plan.
What do you think?

 

Again: Good luck.

I would first verify each and every file/directory you put on these keys - use Hashtab (copy each important file to a different computer and compare the MD5 values between the original file on your 'source' computer and the MD5 values on the USB key AND on the test computer you copy the file to - and then and only then would I be thinking about using it as a backup device.

Why am I suggesting this? Because the Patriot Rage 64GB USB keys I bought would corrupt almost any data I put on them (2 of them; both garbage for 'data storage' or any other purposes...).

Yeah, small, easily concealed (and lost) and no way would I depend on two identical keys from the same manufacturer to back up my data.

Your call, really; but highly not recommended to depend on 'cheap' USB keys as your backup solution (at least buy two different brand of keys and test them initially and constantly... (too much work, imo for too little gain...).

Wishing you the best of luck.

 

I see. Well thanks for the good advice, I will definitely put that into consideration.
I'm just sick and tired of costly, bulky and slow optical discs (I backup to BD-R).

 

Hey, no problem.

When I eventually figured out that the USB keys were corrupting my data - I was pissed, but as it was backed up to at least 13 other systems/HDD's - it wasn't too critical to me.

In your case, it could be catastrophic.

Glad I could give you a heads up.

 

Yes, multiple backup locations and preferably an alternate backup medium (i.e. hard drive and optical) are best. However, I've got double backups both on hard drives, but one is external local, one is external stored elsewhere, and most important stuff is on cloud storage.

 

He he... I'm sure you mean most important is also on cloud storage...

I wouldn't trust the 'cloud' much more than I trust flash/ssd's right now.

 

i wouldn't trust the cloud at all, but at least more than no backup at all => it's a nice +1 kinda thing.

i have everything + the cloud.

 

Yes, that is what I meant, primarily photos. I probably have ten duplicates of some form I'm so paranoid of losing them.