Well, well... It appears one of our employees kept "everything" on a USB 
flash drive. And guess what? Yah, that's right. Now every time she tries 
to use that drive, it says the drive isn't formatted.

I have no idea why a working drive would suddenly do this, but it sounds 
quite serious. Anyway, now I have a person begging me to get their data 
back for them.

So what do we think, people? Is there a hope in hell of getting this 
stuff back? How would you go about it?

A quick search with Google reveals an Aladdin's cave of flashy programs 
that promise to get your data back. If you pay money, anyway. Even the 
ones with "FREE!" splashed all over them are actually just demo versions 
that show you the files it could get back if you just pay up with real 
money first. Or maybe you can only recover the first 100 files. Or only 
files under 10 KB in size. Or some other arbitrary limitation to force 
you to buy the full deal.

Dodgy, much?

Anyway, there are a couple of possibilities here:
- The drive is fine, and the PC is broken.
- The drive is OK, but there's a software glitch preventing Windoze from 
reading it.
- The drive is physically OK, but some filesystem data got mangled.
- The drive is actually broken, but most of the data is still readable.
- The drive is toast, and it's no longer possible to read anything at all.

If it's one of the first two, my job is pretty trivial. If it's the last 
one, we're going to have to pay somebody to take the drive apart and 
examine it. If it's either of the middle two possibilities, I basically 
need to copy everything off the drive and examine it somehow.

Copying the entire filesystem off the drive should be a simple matter 
for dd. After that, does anybody have any ideas for how to reconstruct 
the filesystem? (I'm presuming it's going to be FAT16... USB flash 
drives usualy are, aren't they?)

There are dozens of flashy programs that claim to reconstruct 
filesystems, but they all cost money. (After all, people who are too 
stupid to back up there data and need it back in an emergency will pay 
the Earth, right?) Surely reconstructing the broken parts of a 
filesystem isn't actually *that* hard? I mean, there are absolutely 
millions of data recovery programs out there, so it can't be difficult. 
Has nobody written some geeky Linux utility that will do this for free?

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Invisible wrote:
> Well, well... It appears one of our employees kept "everything" on a USB 
> flash drive. And guess what? Yah, that's right. Now every time she tries 
> to use that drive, it says the drive isn't formatted.
> 

> 
> Dodgy, much?
> 
> Anyway, there are a couple of possibilities here:
> - The drive is fine, and the PC is broken.
> - The drive is OK, but there's a software glitch preventing Windoze from 
> reading it.
> - The drive is physically OK, but some filesystem data got mangled.
> - The drive is actually broken, but most of the data is still readable.
> - The drive is toast, and it's no longer possible to read anything at all.
> 
> If it's one of the first two, my job is pretty trivial. If it's the last 
> one, we're going to have to pay somebody to take the drive apart and 
> examine it. If it's either of the middle two possibilities, I basically 
> need to copy everything off the drive and examine it somehow.
> 

The real question is:

How cute is she?

;-o

Post a reply to this message

Tom Austin wrote:

> The real question is:
> 
> How cute is she?
> 
> ;-o

Moderately cute... but very bossy.

She's one of these people who has an attitude that she's important or 
something, and everybody else had better recognise that.

I can do better. ;-)

That *is* of course the real question. But in true geek fashion, I'm 
more intrigued by having an excuse to research the techniques involved 
in data recovery than actually helping this person.

Obligatory XKCD references:
http://xkcd.com/309/
http://xkcd.com/356/

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Invisible <voi### [at] devnull> wrote:
> So what do we think, people?

  I think you should give her a lesson on keeping important data in more
than once place, as well as the importance of regular backupping.

-- 
                                                          - Warp

Post a reply to this message

Warp wrote:

>   I think you should give her a lesson on keeping important data in more
> than once place, as well as the importance of regular backupping.

LOL! Now there's something I won't disagree with. ;-)

You would have *thought* this was already "obvious" to any intelligent 
person - but apparently not...

The only real question is "what do you backup onto?" Personally I can 
think of any number of valid answers - a second USB stick, for example.

(You'll note that my own USB stick is not backed up anywhere. You will 
also note that it contains nothing I wouldn't mind losing.)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Invisible wrote:
> Well, well... It appears one of our employees kept "everything" on a USB 
> flash drive. And guess what? Yah, that's right. Now every time she tries 
> to use that drive, it says the drive isn't formatted.
> 
> I have no idea why a working drive would suddenly do this...

It's no longer a working drive, I'd wager.

Regards,
John

Post a reply to this message

>> I have no idea why a working drive would suddenly do this...
> 
> It's no longer a working drive, I'd wager.

Well, that would indeed be amusing. We shall see. ;-)

Even so, you would think there would have to be some kind of *cause* for 
this. The broken drive has been tried on another machine and found to 
not work there either. However, the person made a comment about a second 
USB drive having recently failed in exactly the same way. This makes me 
rather suspicious...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Invisible wrote:

> Has nobody written some geeky Linux utility that will do this for free?

Well, let me see now...

It appears that Knoppix already contains a program called Test Disk that 
is supposed to reconstruct broken partition tables, and of course there 
is fsck.vfat which is meant to fix broken FAT filesystems.

So it looks like all I need to do (assuming the USB device is readable 
at all) is use dd to dump the contents into a file, and then wave these 
two tools over that file in an attempt to get something usable. 
Shouldn't be too hard...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Invisible wrote:
> 
> Moderately cute... but very bossy.
> 
> She's one of these people who has an attitude that she's important or 
> something, and everybody else had better recognise that.
> 
> I can do better. ;-)
> 

sometimes those scare me
it's like getting a date with the cutest girl in the class -then finding 
she has a squeaky voice and never shuts up


> That *is* of course the real question. But in true geek fashion, I'm 
> more intrigued by having an excuse to research the techniques involved 
> in data recovery than actually helping this person.
> 

You are right.

Way back in the day before hard drives I had the opportunity to repair 
an Apple IIe floppy disk where the file table 'catalog' got blown away.

Luckily I had a 'Disk Doctor' that would edit raw sectors so I could 
rebuild it.

The bad thing was that the 'Disk Doctor' was the one that got blown away.

I managed to fix the disk enough to run the main program so I could fix 
the rest of the disk.  Getting the first one back was murder - due to 
the lack of a good sector editor.

All in all I think I managed to recover everything but one or two files 
that I didn't care about.  Back then disks only held 360k so it wasn't 
all that much work.


Good Luck!



Tom

Post a reply to this message

Tom Austin wrote:
> Invisible wrote:
>>
>> Moderately cute... but very bossy.
>>
>> She's one of these people who has an attitude that she's important or 
>> something, and everybody else had better recognise that.
>>
>> I can do better. ;-)
> 
> sometimes those scare me
> it's like getting a date with the cutest girl in the class -then finding 
> she has a squeaky voice and never shuts up

It's like the one where Brainiac was doing some dubiously scientific 
experiment or other that called for a beautiful women.

"THIS... is Gemma. Gemma... is LOVELY."

Hell yeah, she looks hot!

...and THEN she opened her mouth, and suddenly any interest I had in her 
completely evapourated. I didn't know a voice could do that... o_O

>> That *is* of course the real question. But in true geek fashion, I'm 
>> more intrigued by having an excuse to research the techniques involved 
>> in data recovery than actually helping this person.
> 
> You are right.
> 
> Way back in the day before hard drives I had the opportunity to repair 
> an Apple IIe floppy disk where the file table 'catalog' got blown away.
> 
> Luckily I had a 'Disk Doctor' that would edit raw sectors so I could 
> rebuild it.
> 
> The bad thing was that the 'Disk Doctor' was the one that got blown away.
> 
> I managed to fix the disk enough to run the main program so I could fix 
> the rest of the disk.  Getting the first one back was murder - due to 
> the lack of a good sector editor.
> 
> All in all I think I managed to recover everything but one or two files 
> that I didn't care about.  Back then disks only held 360k so it wasn't 
> all that much work.
> 
> 
> Good Luck!

Heh. Apparently she's going to get the IT department at the place her 
boyfriend works for to try to recover it first. Either she thinks I'm 
incompetent, or she's really in a hurry...

Like I said, I don't really care about her plight - she should have kept 
multiple copies - I'm more interested in the interlectual challenge of 
fixing a broken filesystem. ;-)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

On Tue, 26 Aug 2008 11:50:23 +0100, Invisible wrote:

> Well, well... It appears one of our employees kept "everything" on a USB
> flash drive. And guess what? Yah, that's right. Now every time she tries
> to use that drive, it says the drive isn't formatted.
> 
> I have no idea why a working drive would suddenly do this,

I've read reports that flash storage devices have a limited number of 
write cycles before they become bricks.  I had set up one device with a 
journaling filesystem and had several people comment that this was a bad 
idea because of the limited-use nature of this type of device.

Easy test:  Plug it into another computer and see if you can read it.  If 
you can, it's her PC; if you can't, it's the drive.

Jim

Post a reply to this message

Invisible wrote:
> Dodgy, much?

No. Free samples. If the free version doesn't work, you just saved the 
cost of paying for something that won't work.

No more dodgey than giving away the first level of a game for free, I'd 
think.

> Copying the entire filesystem off the drive should be a simple matter 
> for dd. 

Assuming the hardware is physically OK, yeh.

-- 
Darren New / San Diego, CA, USA (PST)

Post a reply to this message

Jim Henderson <nos### [at] nospamcom> wrote:
> I've read reports that flash storage devices have a limited number of 
> write cycles before they become bricks.

  No need to read "reports". Just read the specs of the flash storage
device.

  However, modern flash storage devices (which work properly) can be
rewritten something like 100 thousand times before they will show any
signs of malfunction.

-- 
                                                          - Warp

Post a reply to this message

I'd suggest using ddrescue to (hopefully) image the drive first, then possibly
photorec to try and recover files.  Sysresccd contains these tools and is awesome.

Post a reply to this message

On Tue, 26 Aug 2008 12:35:10 -0400, Warp wrote:

> Jim Henderson <nos### [at] nospamcom> wrote:
>> I've read reports that flash storage devices have a limited number of
>> write cycles before they become bricks.
> 
>   No need to read "reports". Just read the specs of the flash storage
> device.

<sigh>

I had asked questions about using a journaling filesystem and it was 
told.  Yes, I could've read the specs but I didn't.  So shoot me.

Oh, wait, you just did.

>   However, modern flash storage devices (which work properly) can be
> rewritten something like 100 thousand times before they will show any
> signs of malfunction.

The number I heard was 10,000.  With a JFS, that can happen fairly 
quickly.

Jim

Post a reply to this message

Jim Henderson wrote:
>> rewritten something like 100 thousand times before they will show any

> The number I heard was 10,000. 

It depends on the manufacturing. 10,000 used to be a good number a 
couple of years ago. (Originally it was closer to 1000.) Newer versions 
do more, with development driven by things like cell phones needing to 
store text messages and etc in flash.

-- 
Darren New / San Diego, CA, USA (PST)

Post a reply to this message

On Tue, 26 Aug 2008 10:01:04 -0700, Darren New wrote:

> Jim Henderson wrote:
>>> rewritten something like 100 thousand times before they will show any
> 
>> The number I heard was 10,000.
> 
> It depends on the manufacturing. 10,000 used to be a good number a
> couple of years ago. (Originally it was closer to 1000.) Newer versions
> do more, with development driven by things like cell phones needing to
> store text messages and etc in flash.

Makes sense. :)

Jim

Post a reply to this message

Invisible wrote:
> 
> She's one of these people who has an attitude that she's important or 
> something, and everybody else had better recognise that.
> 

The data on that stick is not recoverable.

-- 
Eero "Aero" Ahonen
    http://www.zbxt.net
       aer### [at] removethiszbxtnetinvalid

Post a reply to this message

Invisible wrote:
> 
> Even so, you would think there would have to be some kind of *cause* for 
> this. The broken drive has been tried on another machine and found to 
> not work there either. However, the person made a comment about a second 
> USB drive having recently failed in exactly the same way. This makes me 
> rather suspicious...
> 

She might be removing[1] them without removing[2] them.

[1] Physically
[2] By the eject -command

-- 
Eero "Aero" Ahonen
    http://www.zbxt.net
       aer### [at] removethiszbxtnetinvalid

Post a reply to this message

"Invisible" <voi### [at] devnull> wrote in message
news:48b3dff5$1@news.povray.org...

> A quick search with Google reveals an Aladdin's cave of flashy programs
> that promise to get your data back. If you pay money, anyway. Even the
> ones with "FREE!" splashed all over them are actually just demo versions
> that show you the files it could get back if you just pay up with real
> money first. Or maybe you can only recover the first 100 files. Or only
> files under 10 KB in size. Or some other arbitrary limitation to force
> you to buy the full deal.
>
> Dodgy, much?
>
> There are dozens of flashy programs that claim to reconstruct
> filesystems, but they all cost money.

Yes. Such is life. Bread costs money. Milk costs money. Electricity costs
money. Coffee costs money. And so *drum roll*, software costs money.
Programmers are not magicians, they need money to live just like everybody
else. So what's wrong with *paying* for software? Do you call bakers "dodgy"
too because they may give you a bite size sample but they don't give you
whole loaves of bread for free?

Of course it's not your fault that you have no respect for software
developers, it's their own making. The problem with is that academics have
given away too much for too long, and they can afford to do that because
they are not giving away their own time but government's or the
institution's time. Contrast this with, say, milk. There are no government
funded farmer academicians who take it upon themselves to give out free
milk, not that the same thing would even work for physical goods.

Post a reply to this message

"John VanSickle" <evi### [at] hotmailcom> wrote
> Invisible wrote:

> > Well, well... It appears one of our employees kept "everything" on a USB
> > flash drive. And guess what? Yah, that's right. Now every time she tries
> > to use that drive, it says the drive isn't formatted.

> > I have no idea why a working drive would suddenly do this...

> It's no longer a working drive, I'd wager.

Techncially, those aren't even "drives".

Post a reply to this message

Invisible wrote:
> Well, well... It appears one of our employees kept "everything" on a USB
> flash drive. And guess what? Yah, that's right. Now every time she tries
> to use that drive, it says the drive isn't formatted.

Flash drive? Do you really mean flash memory, or just a USB hard disk with
the normal magnetic system?

Flash memory does "wear out". Write cycles are more limited than you may
expect.

Post a reply to this message

Kyle wrote:
> I'd suggest using ddrescue to (hopefully) image the drive first

Ditto that. Don't use plain dd. The filesystem and other stuff may refuse to
give you data, and I think dd would just halt if a sector is unreadable.
ddrescue continues and tries to copy as much as it can.

Post a reply to this message

> Of course it's not your fault that you have no respect for software
> developers, it's their own making. The problem with is that academics have
> given away too much for too long,

Also because a lot of computer programmers do it only as a hobby, and as 
such they have another source of income so don't mind if they don't get paid 
for their hobby work.  But I wonder why it is different for other hobbies 
like photography, you would never find some unknown person to do your 
wedding for free.  But people are happy to spend *years* writing code and 
then give it away for free to unknown people.  Maybe it says more about the 
sort of people who program as a hobby.

Post a reply to this message

Eero Ahonen wrote:

> She might be removing[1] them without removing[2] them.

Yeah, I can see how that might corrupt the filesystem. But badly enough 
to render it unreadable? You would think you'd just get a few filesystem 
inconsistencies. The error message sounds more like the superblock is 
unreadable or something...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Jim Henderson wrote:

> I had asked questions about using a journaling filesystem and it was 
> told.  Yes, I could've read the specs but I didn't.  So shoot me.

Wear-leveling, anyone?

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Nicolas Alvarez wrote:
> Kyle wrote:
>> I'd suggest using ddrescue to (hopefully) image the drive first
> 
> Ditto that. Don't use plain dd. The filesystem and other stuff may refuse to
> give you data, and I think dd would just halt if a sector is unreadable.
> ddrescue continues and tries to copy as much as it can.

Online resources claim there's an extra option to dd to make it skip 
unreadable blocks.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

>> Dodgy, much?
> 
> Yes. Such is life. Bread costs money. Milk costs money. Electricity costs
> money. Coffee costs money. And so *drum roll*, software costs money.
> Programmers are not magicians, they need money to live just like everybody
> else. So what's wrong with *paying* for software? Do you call bakers "dodgy"
> too because they may give you a bite size sample but they don't give you
> whole loaves of bread for free?

No. But if somebody shouts "FREE STUFF!" and then carefully tricks you 
into having to actually pay money for it... to me, that's very dodgy.

If stuff costs money then fine. But don't claim something is free when 
it isn't. That's deception.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Invisible wrote:
> 
> Heh. Apparently she's going to get the IT department at the place her 
> boyfriend works for to try to recover it first. Either she thinks I'm 
> incompetent, or she's really in a hurry...
> 
> Like I said, I don't really care about her plight - she should have kept 
> multiple copies - I'm more interested in the interlectual challenge of 
> fixing a broken filesystem. ;-)
> 

Is it business data, or personal data?

Call me weird, but it frustrates me when a business problem is so easily 
taken outside.


Tom

Post a reply to this message

>> Like I said, I don't really care about her plight - she should have 
>> kept multiple copies - I'm more interested in the interlectual 
>> challenge of fixing a broken filesystem. ;-)
> 
> Is it business data, or personal data?

Apparently it's a mixture of both - from two seperate businesses... o_O

> Call me weird, but it frustrates me when a business problem is so easily 
> taken outside.

Yeah.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

Invisible wrote:

> (You'll note that my own USB stick is not backed up anywhere. You will 
> also note that it contains nothing I wouldn't mind losing.)

My USB Flash drive is simply a convenient way of moving data from 
Computer A to Computer B where Computer B is not accessible from the 
network. It's nice to have everything I need to run diagnostics on a 
machine in the shop without needing to configure one of those confounded 
USB wireless network adapters that work only half the time, and never 
during lunchtime.

Post a reply to this message

>> (You'll note that my own USB stick is not backed up anywhere. You will 
>> also note that it contains nothing I wouldn't mind losing.)
> 
> My USB Flash drive is simply a convenient way of moving data from 
> Computer A to Computer B where Computer B is not accessible from the 
> network. It's nice to have everything I need to run diagnostics on a 
> machine in the shop without needing to configure one of those confounded 
> USB wireless network adapters that work only half the time, and never 
> during lunchtime.

My USB stick mainly contains diagnostic tools and my assorted 
playthings. (*cough* POV-Ray *cough*) Nothing I couldn't download again 
- or just get another copy off my computer anyway...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

Post a reply to this message

"Invisible" <voi### [at] devnull> wrote in message
news:48b50995$1@news.povray.org...

> If stuff costs money then fine. But don't claim something is free when
> it isn't. That's deception.

I gather you have never come across the expressions like "no free lunch",
"too good to be true"... etc, and that you never ever seen any products
advertisements, be it on TV, radio or in papers. Either that, or you
genuinely belive that a deodorant will make you irresistable to the opposite
sex.

Post a reply to this message

"scott" <sco### [at] scottcom> wrote in message
news:48b500ec$1@news.povray.org...

> > Of course it's not your fault that you have no respect for software
> > developers, it's their own making. The problem with is that academics
have
> > given away too much for too long,

> Also because a lot of computer programmers do it only as a hobby, and as
> such they have another source of income so don't mind if they don't get
paid
> for their hobby work.  But I wonder why it is different for other hobbies
> like photography, you would never find some unknown person to do your
> wedding for free.  But people are happy to spend *years* writing code and
> then give it away for free to unknown people.  Maybe it says more about
the
> sort of people who program as a hobby.

I think it's more of a perception issue based on the logistics of the
situation. A photographer offering free services to random people would have
to deal with customers and be on their terms. When you are actually on
someone else's terms, you feel like you are working. It's a misconception,
of course. Like you said, a programmer can be spending/wasting much more
man-hours, but without an external deadline and project specifications, he
may not feel like he is essentially working for free for somebody else.
There is of course also the portfolio building or competitive aspect, which
is equally misguided (hobby projects count very little at job interviews,
one needs to be able to work under deadlines and specs).

Post a reply to this message

> My USB stick mainly contains diagnostic tools and my assorted playthings. 
> (*cough* POV-Ray *cough*) Nothing I couldn't download again - or just get 
> another copy off my computer anyway...

I picked up a 4GB USB stick for 12 euros or something, and I use it mostly 
to watch movies on the PS3. For some reason the streaming software I'm using 
on the PC (tversity) quite often screws up when you pause the PS3 in the 
middle of a film, meaning you have to start again from the beginning and 
then seek to where you were before (if you remember).  No such problems if I 
just copy it to the memstick first, plus I can turn off the PC while 
watching the film (I don't need any more heat generators in my house at the 
moment!)

Also my little mini-hifi thing in the kitchen has a USB socket, so I 
sometimes put mp3s on the stick for that.

I regret not paying the 200 euro for the USB socket in my car, that would 
save a lot of CD burning and/or cables for the iPod.

Post a reply to this message

> No. But if somebody shouts "FREE STUFF!" and then carefully tricks you 
> into having to actually pay money for it... to me, that's very dodgy.
> 
> If stuff costs money then fine. But don't claim something is free when 
> it isn't. That's deception.

Claim that it's free* instead, then it's fine ;-)

Post a reply to this message

Invisible wrote:

> 
> No. But if somebody shouts "FREE STUFF!" and then carefully tricks you 
> into having to actually pay money for it... to me, that's very dodgy.
> 
> If stuff costs money then fine. But don't claim something is free when 
> it isn't. That's deception.
> 

I generally won't buy if the sample version only serves to be an 
advertisement for the full version. (IOW, I can't really evaluate if it 
will do what I need it to do, sure it tells me I can recover files, but 
will it, and is the level of recovery worth the money I'm about to 
spend?) Otherwise I go by the recommendation of those whose opinions i 
respect. Adobe did it right.. You can get a working version of Photoshop 
and play around with it for 30 days, with premiere elements, it was a 
bit different. You had a 30 day trial, but any movie you created had an 
annoying overlay, which was fine, I could actually see that it fit my 
needs.

The most insidious I've found is some games have a 60 minute trial 
period. You'll be happily playing the game and Bang! you're kicked out 
at 1 hour with a message saying "You can continue playing if you pay up, 
NOW."

Post a reply to this message

Nicolas Alvarez wrote:
> Invisible wrote:
>> Well, well... It appears one of our employees kept "everything" on a USB
>> flash drive. And guess what? Yah, that's right. Now every time she tries
>> to use that drive, it says the drive isn't formatted.
> 
> Flash drive? Do you really mean flash memory, or just a USB hard disk with
> the normal magnetic system?
> 
> Flash memory does "wear out". Write cycles are more limited than you may
> expect.
> 

Our equipment uses CF cards and you'd be surprised at how long they can 
last, given that the equipment constantly writes production logs to the 
card among other things. We do occasionally replace them, but only after 
a couple of years in service at a minimum.

Post a reply to this message

Invisible wrote:
> 
> Yeah, I can see how that might corrupt the filesystem. But badly enough 
> to render it unreadable? You would think you'd just get a few filesystem 
> inconsistencies. The error message sounds more like the superblock is 
> unreadable or something...
> 

Depends on what the computer is doing when the stick is pulled out. 
Think what could happen, if the computer were writing file allocation 
tables...

-- 
Eero "Aero" Ahonen
    http://www.zbxt.net
       aer### [at] removethiszbxtnetinvalid

Post a reply to this message

Eero Ahonen wrote:
> Invisible wrote:
>>
>> Yeah, I can see how that might corrupt the filesystem. But badly 
>> enough to render it unreadable? You would think you'd just get a few 
>> filesystem inconsistencies. The error message sounds more like the 
>> superblock is unreadable or something...
>>
> 
> Depends on what the computer is doing when the stick is pulled out. 
> Think what could happen, if the computer were writing file allocation 
> tables...

Or, say, the superblock. ;-)

-- 
Darren New / San Diego, CA, USA (PST)

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Invisible wrote:
> If stuff costs money then fine. But don't claim something is free when 
> it isn't. That's deception.

That's "Search Engine Optimization".  :-)

-- 
Darren New / San Diego, CA, USA (PST)

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>>> Yeah, I can see how that might corrupt the filesystem. But badly 
>>> enough to render it unreadable? You would think you'd just get a few 
>>> filesystem inconsistencies. The error message sounds more like the 
>>> superblock is unreadable or something...
>>>
>>
>> Depends on what the computer is doing when the stick is pulled out. 
>> Think what could happen, if the computer were writing file allocation 
>> tables...
> 
> Or, say, the superblock. ;-)

Yeah, but AFAIK you only write to the superblock when you initially 
format the volume?

I can understand a file or folder being broken, but the entire FS?

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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>> If stuff costs money then fine. But don't claim something is free when 
>> it isn't. That's deception.
> 
> That's "Search Engine Optimization".  :-)

That's what I said. Deception. :-P

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Invisible wrote:
> Yeah, but AFAIK you only write to the superblock when you initially 
> format the volume?

Hmmm... On FAT? I'm not sure. There might be a flag there that marks 
whether the drive was dismounted cleanly or not. Or if you screw up the 
root directory, I can see that mucking things up too. If there were just 
a couple of directories, and the first sector of the root directory got 
scrambled because she pulled it out while it was writing, I can see that 
messing things up.

> I can understand a file or folder being broken, but the entire FS?

FAT usually has two FATs, too, for just such a reason. It's possible she 
got a warning that the first was broken and just ignored it until the 
second got messed up too.

I'm not real sure of the electrical characteristics of a USB stick such 
that it gets the whole chip messed up by being pulled out while writing, 
but I have to believe avoiding that was one of the design goals.

-- 
Darren New / San Diego, CA, USA (PST)

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Invisible wrote:
>>> If stuff costs money then fine. But don't claim something is free 
>>> when it isn't. That's deception.
>>
>> That's "Search Engine Optimization".  :-)
> 
> That's what I said. Deception. :-P

I'm not disagreeing. :-)

I was told by someone at google that the two highest cost ads are for 
"data recovery" and for "mesothelioma" (the cancer you get from asbestos).

-- 
Darren New / San Diego, CA, USA (PST)

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On Wed, 27 Aug 2008 08:57:11 +0100, Invisible wrote:

> Jim Henderson wrote:
> 
>> I had asked questions about using a journaling filesystem and it was
>> told.  Yes, I could've read the specs but I didn't.  So shoot me.
> 
> Wear-leveling, anyone?

Probably contributes to the increased life of the devices these days.

Jim

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Darren New wrote:
> Invisible wrote:
>> Yeah, but AFAIK you only write to the superblock when you initially 
>> format the volume?
> 
> Hmmm... On FAT? I'm not sure. There might be a flag there that marks 
> whether the drive was dismounted cleanly or not. Or if you screw up the 
> root directory, I can see that mucking things up too. If there were just 
> a couple of directories, and the first sector of the root directory got 
> scrambled because she pulled it out while it was writing, I can see that 
> messing things up.

Yeah. Well it's not complaining the filesystem is broken, it claims that 
there *is* not filesystem at all. That's what I find so puzzling...

>> I can understand a file or folder being broken, but the entire FS?
> 
> FAT usually has two FATs, too, for just such a reason. It's possible she 
> got a warning that the first was broken and just ignored it until the 
> second got messed up too.
> 
> I'm not real sure of the electrical characteristics of a USB stick such 
> that it gets the whole chip messed up by being pulled out while writing, 
> but I have to believe avoiding that was one of the design goals.

As I understand it, to write to flash RAM, you erase a small block and 
then completely re-flash it. If that got interrupted, your whole block 
is gone.

No idea how large a flash block is - I'll bet it isn't the same size as 
a filesystem block! ;-)

You'd think a tiny little capacitor would keep the electronics running 
for enough split seconds to shutdown vaguely cleanly... *shrugs*

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Orchid XP v8 wrote:
> Yeah. Well it's not complaining the filesystem is broken, it claims that 
> there *is* not filesystem at all. That's what I find so puzzling...

Right. The superblock (i.e., the boot block) holds a table that says 
where the file system is, how many blocks are in it, which block the 
root directory starts on, and so on. If that got wiped, then no, you 
don't have any file system. :)

> No idea how large a flash block is - I'll bet it isn't the same size as 
> a filesystem block! ;-)

I imagine it depends.

> You'd think a tiny little capacitor would keep the electronics running 
> for enough split seconds to shutdown vaguely cleanly... *shrugs*

Not when you're writing flash. That tends to take a lot of current.

-- 
Darren New / San Diego, CA, USA (PST)

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>> Yeah. Well it's not complaining the filesystem is broken, it claims 
>> that there *is* not filesystem at all. That's what I find so puzzling...
> 
> Right. The superblock (i.e., the boot block) holds a table that says 
> where the file system is, how many blocks are in it, which block the 
> root directory starts on, and so on. If that got wiped, then no, you 
> don't have any file system. :)

I can see how that would be. What I don't see is why the hell you would 
ever be writing data to anywhere near this location...

That again, I have no idea how FAT works.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Orchid XP v8 wrote:
> I can see how that would be. What I don't see is why the hell you would 
> ever be writing data to anywhere near this location...

Flash isn't like a disk drive. It's electronic. If you zap the 
electronics by (for example) pulling it out while it's writing, I don't 
know what it would mess up.

And, as I said, there *is* a flag somewhere, I think, that says whether 
the disk needs to be checked when remounted.  I *think* that's in the 
root block.

-- 
Darren New / San Diego, CA, USA (PST)

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