PeteCresswell said:
The devices are unlocked (i.e. the little physical tab is in the
correct position) But XP says the card is locked. Plug it into my
Windows 7 laptop, and there's no problem: I can write to and/or
format the card.
Possibly due to difference in the security programs (e.g., anti-virus,
HIPs) or tweakers you installed on the different hosts. Or different
card readers in each host: one supports your card and the other doesn't
not, especially a problem if you're using a newer SDHC card in an old
card reader that only knows the SD format.
Found several discussions around
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies]
"WriteProtect"=dword:00000000
Stumbled around with that a little, but no joy. The articles I read
assumed that the key already existed and just had tb changed. On my
instance of XP, there isn't even a "StorageDevicePolicies" folder (or
whatever the proper term is....)
Well, if a registry data item isn't defined (whatever value) which means
the data item itself isn't defined or the registry key under which it
would reside doesn't exist then the default value gets used. If you
want to use something other than the default value when the item is
missing, you'll have to create the registry key, if needed, and the data
item to specify a different value for it than the default.
LOTS of registry data items or their registry keys don't exist. No
point in adding them if a default gets assumed when they're missing.
From
http://support.microsoft.com/kb/555443, it appears the default
value (when missing) is zero (0) which is probably what you want.
Values under the HKU hive (replicated under the HKCU hive) will override
the system settings under the HKLM hive. Did you ever check if there
was an equivalent "StorageDevicePolicies" data item under the following
key?
HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Control
Sometimes Windows will check if there is a HKU version of a registry
entry (data item) and use it to override the system-wide HKLM entry, but
not always (i.e., there is no recognized HKU version of the HKLM entry).
First guess is that I created the wrong kind of object within the
StorageDevicePolicies thingie.
From the MS article, you create a data item named "StorageDevicePolices"
that is a DWORD item type. I am assuming the registry key
(HKLM\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies) does
already exist.
Alteratively, while logged in under an admin-level account, use the
group policy editor (gpedit.msc) to create that policy definition (not
available in the Home edition of Windows XP - you didn't mention WHICH
edition of Windows XP you have). This USB policy is not normally
exposed by gpedit but you can define and import a policy template to add
it so it shows in gpedit. See:
http://www.windowsitpro.com/article/usb/q-how-can-i-set-usb-devices-to-read-only-via-group-policy-
The pics in that article show gpedit for a server version of Windows.
gpedit for the workstation versions will have a different tree. I
suspect once you import the template by right-clicking on the "Computer
Configuration -> Administrative Templates" tree node and import the
template that it will appear under that tree node.
The following article has a couple links to .reg files to enable/disable
this policy. That's probably the easiest way for you to go. Save the
..reg files somewhere and just double-click on them in Windows Explorer.
You'll get prompted by Windows as to whether or not you really want to
apply the changes in the .reg file you double-clicked.
http://www.howtogeek.com/howto/windows-vista/registry-hack-to-disable-writing-to-usb-drives/
You can also use the reg.exe command to perform registry deletes, adds,
and edits (handy to use inside of .bat or .cmd batch files) but using a
..reg file is easier for you.
As noted in the articles, you need to REBOOT after making the change to
effect that change. This is a hardware behavior that has to be
established when Windows starts up, not afterward and not after you have
logged in.
Then the problem might not be with Windows or with the SD card but with
the card reader. They aren't that sturdy and I've seen many users abuse
them by not correctly aligning the card and just slapping them in. They
damage the finger contacts in the connector inside the slot reader.
http://www.camerahacker.com/Forums/...o_CF_adapter..files.hidden/facfsd2_inside.jpg
See those bent finger contacts? If them get smashed down to make
unreliable contact or get misaligned, the slot reader won't work
correctly. Big fingers (by comparison), little flash cards, fragile
contact fingers don't mix well for durability and then add users that
don't gently insert the card but smack it in.
However, I don't see a particular connection that puts the SD card in
"locked" mode unless its the card detection signal. For the SD pinout,
see:
http://pinouts.ru/Memory/sdcard_pinout.shtml
From the following pic, I can't tell what circuit is affected by the SD
lock switch:
http://www.electronics-lab.com/blog/wp-content/uploads/2008/09/2452663566_12438cf29f.jpg
From my reading, whatever the switch does on the SD card can be ignored
by the card reader (so a locked SD card could still be read or, perhaps
due to failure in the card reader, an unlocked SD card would be seen as
locked). You didn't mention if you tried a different SD card in the
card reader you have in your Windows XP host. From:
http://wiki.answers.com/Q/How_can_y...ock_bottom_is_missing_and_your_card_is_locked
that switch on the SD card doesn't affect any logic on the SD card
itself. Instead it's like the old floppy write locks where the absence
of material in a 5.25" floppy at one spot meant the floppy was locked
(you had to put tape over the notch in the floppy) or you slid a plastic
tab in one of two positions in the 3.5" floppy case. These obviously
didn't have any effect on the magnetic floppy inside the floppy case.
They were sensed by the floppy *drive*. Similarly, these plastic locks
in the SD card don't affect anything on the SD card but are read
optically by the card *reader* to determine if the device /should/ be
locked. Well, if the card reader is broken then it could see all SD
card as locked regardless of the position of the plastic tab on the SD
card.
You need to use a *different* known working SD card in the card reader
you are using in your Windows XP host. If that test still fails, or as
an alternative solution, move the card reader from the Windows 7 host to
the Windows XP host and retest.
See the videos at the link in the above article (shown below) on why the
cards looked locked when they're not:
http://camerarepair.blogspot.com/2009/07/simple-fix-for-memory-card-locked-error.html
Of course, we're assuming the plastic slide tab in the SD card is ALL
THE WAY in its unlocked position and somewhere in between. Also notice
the video at time mark 1:58 mentions using the *wrong* TYPE of SD card.
Maybe you are trying to insert an SDHC card into your card reader in
your Windows XP that only supports SD cards whereas the card reader in
your Windows 7 host supports both SD and SDHC cards. Obviously no one
here knows what SD card you have or which card readers are in the
Windows XP and Windows 7 hosts since you didn't mention any technical
details or brand names and model numbers for them.
