Gregg's Nearly Interminable Adventures in Linux Land

[eschwartz]

Originally Posted by Gregg Bell

Good reminder. Thanks. (I just had one go bad on me not long ago.) Curious, though, what do you mean by a "limited number of writes." Like they will only hold data a certain amount of times?

Precisely. The more you use it, the more wear gets put on it, until it eventually refuses to continue working.

But Flash chips are rated for about a million writes, I believe, so a 1GB drive should wear out after writing a million GB of date including erasing adding new stuff and edits.

[eschwartz]

Originally Posted by Dngrsone

Meaning you can write to a location only so many times. Granted, that number is probably up in the five or six figures, now, but still...

I killed my first thumb drive by running Firefox portable on it with caching enabled-- lasted all of three months, I think. Lucky for me, those things still had lifetime warranties on 'em.

the only thing worse than caches would be defragging it!

As I said I'm pretty sure that number is one million. Most drive are lost before their limit comes up, and I believe they fail gradually as more and more of the available memory fails after being worn down. The Flash controller will mark bits as being dead.

[Dngrsone]

Originally Posted by eschwartz

the only thing worse than caches would be defragging it!

As I said I'm pretty sure that number is one million. Most drive are lost before their limit comes up, and I believe they fail gradually as more and more of the available memory fails after being worn down. The Flash controller will mark bits as being dead.

Well, that was in the early days of Flash... I actually wore out that Kingston 512KB stick three times and got it replaced under warranty each time before it got lost... by then, the smallest one readily available was a 2GB stick, which still resides in my pocket, though I prefer using 16 or 32GB drives now.

[Gregg Bell]

Thanks guys for the explanations. A million writes. Uh, don't think I'll come anywhere near that. I'm not hard on them at all. But I do have a thing for them. I don't what it is, just having all that information stored on them. It's just fantastic somehow, and now that they're getting so cheap...yeah, I have a thing for them.

[DMcCunney]

Actually, the limitation is about 100,000 writes per cell. (A cell is roughly equivalent to a cluster on a standard hard drive.) The onboard controller circuitry attempts to transparently move data from failing cells to good ones and mark the failed cells as unusable, so what you'll see, if you see anything, is graceful degradation in the form of decreased storage space.

Since data is read from things like Flash and SSD drives far more often than it is written to them, the odds are that you will upgrade to a larger, faster drive long before you actually notice any wear and tear.

I wouldn't be overly concerned.
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Dennis

[eschwartz]

A hundred thousand, a million, what's the diff?

Knew it was something like that.

[Dngrsone]

An order of magnitude. A decade, a century...

[Gregg Bell]

Originally Posted by DMcCunney

Actually, the limitation is about 100,000 writes per cell. (A cell is roughly equivalent to a cluster on a standard hard drive.) The onboard controller circuitry attempts to transparently move data from failing cells to good ones and mark the failed cells as unusable, so what you'll see, if you see anything, is graceful degradation in the form of decreased storage space.

Since data is read from things like Flash and SSD drives far more often than it is written to them, the odds are that you will upgrade to a larger, faster drive long before you actually notice any wear and tear.

I wouldn't be overly concerned.
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Dennis

Thanks Dennis. I've noticed that less and less storage space on a flash drive and always wondered why.

Originally Posted by eschwartz

A hundred thousand, a million, what's the diff?

Knew it was something like that.

Thanks a lot, eschwartz. I was counting on a million!

Originally Posted by Dngrsone

An order of magnitude. A decade, a century...

Good analogy.

[Gregg Bell]

Hidden files. What is up with them? I noticed these files with tildes after them. So I found out they were backups of files made in text editors. Then I found that they were hidden. But not all of them were hidden. Think they're worth having around or should I shut off the area in preferences (in the text editors) where they are checked?

[Dngrsone]

I would say it depends on the file... if it's something that you have finalized, then you probably don't need to undo the last few edits and you can get rid of the hidden file (but always have a backup file somewhere).

[DMcCunney]

Originally Posted by Gregg Bell

Thanks Dennis. I've noticed that less and less storage space on a flash drive and always wondered why.

Less and less space for reasons other than storing stuff on it?

You will always see a bit less space than the stated size of the drive, because the stated size is the raw size, but formatting takes a bit off the top.

I'd be a bit startled if you saw less space due to cells being marked bad and mapped out. It's going to take a while for any cell to actually get erased and rewritten over 100,000 times.
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Dennis

[DMcCunney]

Originally Posted by Gregg Bell

Hidden files. What is up with them? I noticed these files with tildes after them. So I found out they were backups of files made in text editors. Then I found that they were hidden. But not all of them were hidden. Think they're worth having around or should I shut off the area in preferences (in the text editors) where they are checked?

On Unix systems, and Linux systems whose design derives from Unix, files whose name begins with a . are not shown in a directory listing. To see them, you must do "ls -a".

Many things create hidden files. They are where config files for programs you use are normally kept. The program will have a master config file, usually in the /etc hierarchy, and local ones in the user's home directories, which will override the settings in the global file if they exist. For instance, your shell will have a .profile or a .login file.

Text editors are likely to create journal or backup copy files as hidden, because the odds are you don't want to see them cluttering up a directory display. (They are easy enough to see if you want to.)

Whether they are worth keeping is a judgement call. Which editors do you have installed? How likely are you to need to revert to a backup of what you were editing? The editor may have a configuration setting that will let you turn off keeping a backup if you don't need them. The amount of space they take is unlikely to be a concern, so the question is "Do you need the backups?" Since you don't by default see the backup files unless you did something like alias ls to ls -a in your shell, you probably don't care that hard that they exist.
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Dennis

[DMcCunney]

Originally Posted by Dngrsone

Well, that was in the early days of Flash... I actually wore out that Kingston 512KB stick three times and got it replaced under warranty each time before it got lost... by then, the smallest one readily available was a 2GB stick, which still resides in my pocket, though I prefer using 16 or 32GB drives now.

That's actually not a surprise. Kingston is one the the budget lines, and you get what you pay for.

There are about five outfits that actually make the flash media used in the drive. Everyone who sells flash drives buys media from one of them and puts it in their own packaging with their own logo.

Years back, I bought a PNY SD card for use in a PDA, and did some benchmarks. The PNY had read speeds comparable to the Sandisk and Lexar Media SD cards I already had, but write speeds were an order of magnitude slower. (It took so long to perform the write test I thought the device had hung and was about to reset it.) It turned out the drive uses Toshiba media. A correspondent on a PDA focused web board saw the same issue with Kingston SD cards, which also used Toshiba media.

(I also had an Adata card fail when the plastic packaging did - the glue holding the halves together failed.)

I decided to stick to Sandisk, which is one of the outfits that does make its own flash. It cost a bit more, but I had less quality worries.
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Dennis

[Gregg Bell]

Originally Posted by Dngrsone

I would say it depends on the file... if it's something that you have finalized, then you probably don't need to undo the last few edits and you can get rid of the hidden file (but always have a backup file somewhere).

Thanks Dngrsone. That makes sense. So the hidden files are just single copies of the latest regular file, right? I mean, you don't get a hidden file for every time you save something, right?

[eschwartz]

Originally Posted by Gregg Bell

Thanks Dngrsone. That makes sense. So the hidden files are just single copies of the latest regular file, right? I mean, you don't get a hidden file for every time you save something, right?

Correct. Each time you save, the current version (before the editing) is backed to filename~ before the newly edited version is saved to filename -- you can however edit those backups too and they will be backed up in turn, to filename~~. Why anyone might want to do so, I do not know. There are better document version tracking methods. I only mention this as a fun fact.