USB memory sticks

  • Thread starter Thread starter Jack Sheet
  • Start date Start date
J

Jack Sheet

Probably the wrong newsgroup for this question, but I could not find a
relevant one.

I have a 4Gb USB memory stick. It is nearly full of data. I decide to
delete it all, so I open Windows explorer, point it at the memory stick root
directory, select all and hit the delete key. The progress bar suggests
that I wait for about 50 minutes for it to complete. 50 MINUTES????

I am not using some forensic wipedisk program that over-writes each bit with
random 0 and 1 characters. I thought all that it needed to do was to delete
the reference to the address of the start of each file from the file
allocation table.

Any clue what gives? Thanks
 
Could be right, the 50 minutes. 4 gigs is a heap of data. It'll take time
especially if it's USB 1.

I suggest you do the delete operation just before going to dinner and let it
work.
 
You misunderstand my point, I think.
Normally, when you delete a file from a disk drive, the data remains stored
on the drive. All that you delete is the reference in the file allocation
table to the address of the beginning of the file, so that the operating
system regards the area formerly occupied by the data as free to be
overwritten. Until the data is overwritten it is potentially recoverable
simply by restoring the address of the beginning of the file to the file
allocation table. That information (in the file allocation table) is a very
small quantity of data that is not dependent on file size. So, if you had a
single 4Gb file on the drive that you wished to delete it should take no
longer to do so than a file of 1Kb. That would take a blink of an eye,
rather than 50 minutes.

Unless you are concerned about data security, that is a fast and acceptable
way of deleting data, especially where you are only deleting it because you
need to free up drive space in order for immediate use.

Of course data security can be an issue, and where it is an issue utilities
exist to delete not only the entry in the file allocation table but also to
sweep the entire memory area with zeros so that the data is irrecoverable (I
gather that this is still not wholly effective in all cases, because
forensics can pick up residual charge).

Given the amount of time that it takes to delete a 4Gb memory stick I have
to assume that it is doing a "forensic sweep" of the whole of the memory
area. I would like to have the CHOICE of doing a fast-delete that simply
frees up the memory without deleting the underlying data. Given that choice
I would expect the normal file delete action to assume its normal default
treatment, ie the fast-delete method, and leave it to me to use Norton
Wipedisk or similar if I really want it cleaned.
 
Jack said:
Probably the wrong newsgroup for this question, but I could not find a
relevant one.

I have a 4Gb USB memory stick. It is nearly full of data. I decide to
delete it all, so I open Windows explorer, point it at the memory stick root
directory, select all and hit the delete key. The progress bar suggests
that I wait for about 50 minutes for it to complete. 50 MINUTES????

I am not using some forensic wipedisk program that over-writes each bit with
random 0 and 1 characters. I thought all that it needed to do was to delete
the reference to the address of the start of each file from the file
allocation table.

Any clue what gives? Thanks
Click to expand...

It's not about the gigabytes, it's about the number of
files. For FAT formatted removable drives there is
virtually no write caching under XP. Everyone believes
that this can be activated by the 'Optimize for performance'
policy, but this is not true for removable drives. It indeed
works for 'local disks' as USB harddrives are.

For a flash drive it means hard work. Flash memory can
be written only when it has been erased before. So, the
controller in the flash drive has to read a whole flash
block of usually 64KB, merge the some altered bytes and
write it back into a spare block. A spare block is a flash
block that has been erased earlier and therefor is ready
to be written. The former used block is erased in the
background and becomes a spare block.

Because of the lack of write caching this procedure has
to be done once for every single file. This isn't good
for the drive and not good for the users nerves.
All because Microsofts thinks that all XP users are
idiots who are not able to wait until the drives lamp
stops flashing.
http://www.uwe-sieber.de/usbstick#cache


Uwe
 
Uwe Sieber said:
It's not about the gigabytes, it's about the number of
files. For FAT formatted removable drives there is
virtually no write caching under XP. Everyone believes
that this can be activated by the 'Optimize for performance'
policy, but this is not true for removable drives. It indeed
works for 'local disks' as USB harddrives are.

For a flash drive it means hard work. Flash memory can
be written only when it has been erased before. So, the
controller in the flash drive has to read a whole flash
block of usually 64KB, merge the some altered bytes and
write it back into a spare block. A spare block is a flash
block that has been erased earlier and therefor is ready
to be written. The former used block is erased in the
background and becomes a spare block.

Because of the lack of write caching this procedure has
to be done once for every single file. This isn't good
for the drive and not good for the users nerves.
All because Microsofts thinks that all XP users are
idiots who are not able to wait until the drives lamp
stops flashing.
http://www.uwe-sieber.de/usbstick#cache


Uwe
Click to expand...

Thanks for that. You say it "isn't good for the drive". Can you expand on
that? Is there a limit on the number of times the memory can be re-written?
 
Jack said:
Thanks for that. You say it "isn't good for the drive". Can you expand on
that? Is there a limit on the number of times the memory can be re-written?
Click to expand...

Yes, flash memory 'wears out'. About 100.000 writes a guaranteed
but most cells make by far more. The flash controller tries to
spread the use to all blocks. This is called wear levelling:
http://en.wikipedia.org/wiki/Wear_levelling

There are about 3 percent reserve blocks. If the controller detects
a block as defective, it's marked as such and not used anymore.
When all reserve blocks are eaten up, then the drive or the flash
card starts acting faulty.


Uwe
 
Uwe Sieber said:
Yes, flash memory 'wears out'. About 100.000 writes a guaranteed
but most cells make by far more. The flash controller tries to
spread the use to all blocks. This is called wear levelling:
http://en.wikipedia.org/wiki/Wear_levelling

There are about 3 percent reserve blocks. If the controller detects
a block as defective, it's marked as such and not used anymore.
When all reserve blocks are eaten up, then the drive or the flash
card starts acting faulty.


Uwe
Click to expand...

Thanks for that. I can live with 100000. By the time it becomes unusable
the entire technology will be obsolete. Or a stick will cost as much as a
paperclip.
 
Jack Sheet said:
Thanks for that. I can live with 100000. By the time it becomes unusable
the entire technology will be obsolete. Or a stick will cost as much as a
paperclip.
Click to expand...

Come to think of it, it will probably be destroyed by an EMP before it wears
out.
 
Just do a quick format.

Your data protection scheme has to write all 4 GB, so turn
it off and delete the files or do the quick format.



message | Could be right, the 50 minutes. 4 gigs is a heap of data.
It'll take time
| especially if it's USB 1.
|
| I suggest you do the delete operation just before going to
dinner and let it
| work.
|
|
| --
| Don
| Vancouver, USA
|
|
| | > Probably the wrong newsgroup for this question, but I
could not find a
| > relevant one.
| >
| > I have a 4Gb USB memory stick. It is nearly full of
data. I decide to
| > delete it all, so I open Windows explorer, point it at
the memory stick
| > root directory, select all and hit the delete key. The
progress bar
| > suggests that I wait for about 50 minutes for it to
complete. 50
| > MINUTES????
| >
| > I am not using some forensic wipedisk program that
over-writes each bit
| > with random 0 and 1 characters. I thought all that it
needed to do was to
| > delete the reference to the address of the start of each
file from the
| > file allocation table.
| >
| > Any clue what gives? Thanks
| >
| >
|
|
 
Thanks for that.
Quick format seemed to work fine. Regarding the alternative, how do you
turn off the data protection scheme?
 
Data protection would be some third-party software you have
installed. Check to see what program and what controls it
offers.


message | Thanks for that.
| Quick format seemed to work fine. Regarding the
alternative, how do you
| turn off the data protection scheme?
|
in message
| | > Just do a quick format.
| >
| > Your data protection scheme has to write all 4 GB, so
turn
| > it off and delete the files or do the quick format.
| >
| >
| >
| > message | > | Could be right, the 50 minutes. 4 gigs is a heap of
data.
| > It'll take time
| > | especially if it's USB 1.
| > |
| > | I suggest you do the delete operation just before
going to
| > dinner and let it
| > | work.
| > |
| > |
| > | --
| > | Don
| > | Vancouver, USA
| > |
| > |
| > | | > | > Probably the wrong newsgroup for this question, but
I
| > could not find a
| > | > relevant one.
| > | >
| > | > I have a 4Gb USB memory stick. It is nearly full of
| > data. I decide to
| > | > delete it all, so I open Windows explorer, point it
at
| > the memory stick
| > | > root directory, select all and hit the delete key.
The
| > progress bar
| > | > suggests that I wait for about 50 minutes for it to
| > complete. 50
| > | > MINUTES????
| > | >
| > | > I am not using some forensic wipedisk program that
| > over-writes each bit
| > | > with random 0 and 1 characters. I thought all that
it
| > needed to do was to
| > | > delete the reference to the address of the start of
each
| > file from the
| > | > file allocation table.
| > | >
| > | > Any clue what gives? Thanks
| > | >
| > | >
| > |
| > |
| >
| >
|
|
 
Jack,
I have the 1 gig SanDisk Titanium that came with U3 protection software
installed on it. I too wanted to remove the protection software because it
slowed me down when using the "stick". SanDisk provided me the where and
how to remove it but it is a lengthy note. I'll put it on my website for
download.

www.vanusa.org "Odds, Ends and Funny Things page". Look for the statement
SanDisk U3 removal. It also tells how to reinstall the U3 protection.

Give me 15 minutes to get it there.
 
Thanks - the stick that I am using is a "Peak" make (see
www.peakhardware.com)

I have absolutely no idea what if any protection software is built into it.
All a bit of a black art. Like your website by the way.
 
Thanks for the comp on the website. It's Sons of Italy site I do the
Webmastering on. Besides inviting Italians and those who wish they were
Italians to come visit us on lodge nite, it has a password protected area
for the members to download information, i.e., Directory updates, forms,
news etc.

ciao,

don
 
I am still a bit confused by this.

When I buy a memory stick (and I have several, all different makes) I never
have to install any software. I plug it into the puter and as Foghorn
Leghorne would say "Awaaayyy we gooo". The first time I use a new one I get
little balloons popping up saying "found new hardware", but that is about
it. Does this mean that I do not have any "data protection" installed if I
have not done anything to install it? I do note that had I been on a Windows
98 machine instead of XP then I would have to download and install a driver.
But not with XP - I suppose the driver comes with Windows XP?
 
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