USB flash drive - can read but can't write

[jamarno]

I have a USB thumb drive that my computers can read but can't write.
It has a read-only switch, SPDT, but flipping it makes no difference,
nor does unsoldering it and replacing it with a jumper wire. Is there
something else that may work, such as running a special utility (The
manual refers to a "recovery disk," but the driver CD contains no such
thing) or shorting a certain reset pin?.

This device uses an OTI 6828 USB bridge chip and was distributed by
Pretec as the iDisk and also given out by Microsoft years ago (they
have nothing on it), but I can't find any information about it.

 

[David A.Lethe]

I have a USB thumb drive that my computers can read but can't write.
It has a read-only switch, SPDT, but flipping it makes no difference,
nor does unsoldering it and replacing it with a jumper wire. Is there
something else that may work, such as running a special utility (The
manual refers to a "recovery disk," but the driver CD contains no such
thing) or shorting a certain reset pin?.

This device uses an OTI 6828 USB bridge chip and was distributed by
Pretec as the iDisk and also given out by Microsoft years ago (they
have nothing on it), but I can't find any information about it.

Flash memory has a limited number of writes .. is it possible you have
reached the limitation? You did mention it is several years old, so
it could be using an older flash techology that has severe constraints
on the maximum number of writes. What does the OS log reveal when
you attempt to write . .you should get some good info by querying the
log.

David

 

[Franc Zabkar]

I have a USB thumb drive that my computers can read but can't write.
It has a read-only switch, SPDT, but flipping it makes no difference,
nor does unsoldering it and replacing it with a jumper wire. Is there
something else that may work, such as running a special utility (The
manual refers to a "recovery disk," but the driver CD contains no such
thing) or shorting a certain reset pin?.

This device uses an OTI 6828 USB bridge chip and was distributed by
Pretec as the iDisk and also given out by Microsoft years ago (they
have nothing on it), but I can't find any information about it.

The OTI chip has a Flash Write Protect signal on pin 18
(http://www.costar.com.tw/pdf/OTi/Oti-6828.pdf). Have you verified
that it changes state according to the position of the read-only
switch?

Have you tried to format the drive? Is it possible that the directory
you are trying to write to has a read-only attribute???

- Franc Zabkar

 

[jamarno]

The OTI chip has a Flash Write Protect signal on pin 18
(http://www.costar.com.tw/pdf/OTi/Oti-6828.pdf). Have you verified
that it changes state according to the position of the read-only
switch?

Have you tried to format the drive? Is it possible that the directory
you are trying to write to has a read-only attribute???

Thank you, Frank. That's great in formation. I'll take a look at pin
18.

I had no luck formatting the drive, and nothing had the read-only
attribute enabled.

 

[Franc Zabkar]

Thank you, Frank. That's great in formation. I'll take a look at pin
18.

I had no luck formatting the drive, and nothing had the read-only
attribute enabled.

IIRC, someone with a similar problem found that there was a limit to
the number of files you could have in the drive's root directory. But
this doesn't explain your inability to format the drive ...

- Franc Zabkar

 

[Arno Wagner]

On 1 Jun 2006 20:25:19 -0700, (e-mail address removed) put finger to
keyboard and composed:

IIRC, someone with a similar problem found that there was a limit to
the number of files you could have in the drive's root directory.

That is a FAT limitation: All directories expand as needed,
except the root directory. You should still be able to rename
files and directories there and you should be able to write
in subdirectories. (The limitation is a design error IMO.)

But
this doesn't explain your inability to format the drive ...

What about this: The drive has exhausted its supply of spare
sectors and goes into a safe read-only mode now. Would be a sensible
failure mode, because the user can at least get his/her data of
the drive and there is no risk of failed writes.

Arno

 

[Franc Zabkar]

That is a FAT limitation: All directories expand as needed,
except the root directory. You should still be able to rename
files and directories there and you should be able to write
in subdirectories. (The limitation is a design error IMO.)


What about this: The drive has exhausted its supply of spare
sectors and goes into a safe read-only mode now. Would be a sensible
failure mode, because the user can at least get his/her data of
the drive and there is no risk of failed writes.

Arno

But if the user requested a format, wouldn't that tell the drive's
smarts that the data wasn't of any consequence?

- Franc Zabkar

 

[Tom MacIntyre]

IIRC, someone with a similar problem found that there was a limit to
the number of files you could have in the drive's root directory. But
this doesn't explain your inability to format the drive ...

Hmmm...that's the way it is with floppies, 512 files maximum for FAT12
file system, something like that.

Tom

 

[Rod Speed]

Hmmm...that's the way it is with floppies, 512 files maximum for FAT12
file system, something like that.

You can actually specify more at format time.

 

[Jamie]

IIRC, someone with a similar problem found that there was a limit to
the number of files you could have in the drive's root directory. But
this doesn't explain your inability to format the drive ...

- Franc Zabkar

on the side of the unit (at least mine) there is a lock switch that will
not allow a write or format.
this is a PNY drive stick.

 

[Michael Kennedy]

Did you even read his post?

It has a read-only switch, SPDT, but flipping it makes no difference,
nor does unsoldering it and replacing it with a jumper wire.

 

[Michael Kennedy]

Well I will give you some credit.. The write protect switch was the first
thing I thought of also.

- Mike

Did you even read his post?

 

[Arno Wagner]

On 3 Jun 2006 00:49:43 GMT, Arno Wagner <[email protected]> put finger to
keyboard and composed:

But if the user requested a format, wouldn't that tell the drive's
smarts that the data wasn't of any consequence?

A "format" ooperation on Windows is not a format. MS confused the
terms. For hard-sectored devices like HDDs or memory sticks a "format"
on Windows is actually filesystem creation and on most other OSes it
is called that. Filesystem creation looks to the drive just like
ordinary writes, nothing special about them. So if the device refuses
writes, it consequentially also refuses "formats".

Arno

 

[JANA]

With these drives, when they fail, I replace them. I am on my third one in
about 6 months. I think static electricity in my pockets or something else
is damaging them.

--

JANA
_____

The OTI chip has a Flash Write Protect signal on pin 18
(http://www.costar.com.tw/pdf/OTi/Oti-6828.pdf). Have you verified
that it changes state according to the position of the read-only
switch?

Have you tried to format the drive? Is it possible that the directory
you are trying to write to has a read-only attribute???

Thank you, Frank. That's great in formation. I'll take a look at pin
18.

I had no luck formatting the drive, and nothing had the read-only
attribute enabled.

 

[Michael Kennedy]

Can you re-partition it?
Fdisk or for xp disk management..

Just a thought.. probably won't work either, but I'd give it a try.

- Mike

 

[Michael Kennedy]

yeah it happens to the best of us

sorry, i must of missed that.
btw, i think you have to have it pulled from the USB , set the switch
and then plug it back in.

 

[Jamie]

Did you even read his post?

sorry, i must of missed that.
btw, i think you have to have it pulled from the USB , set the switch
and then plug it back in.

 

[Arno Wagner]

Can you re-partition it?
Fdisk or for xp disk management..

Just a thought.. probably won't work either, but I'd give it a try.

That is also not a special operation from the point of view of
the drive.

Arno

 

[Arno Wagner]

With these drives, when they fail, I replace them. I am on my third one in
about 6 months. I think static electricity in my pockets or something else
is damaging them.

Maybe you just write a lot or a lot of small files?
USB is very well protected against static electicity....

Arno

 

[Franc Zabkar]

With these drives, when they fail, I replace them. I am on my third one in
about 6 months. I think static electricity in my pockets or something else
is damaging them.

AFAIK, a common problem with these is that they develop dry solder
joints at the connector pins, probably due to mechanical stress.

- Franc Zabkar