Chris Walker wrote:
On 04/08/10 17:05, Anthony Anson wrote:
Chris Walker wrote:
Apologies if this appears twice - I posted it to the wrong address, having already posted it using the wrong email address!
I've copied one 2GB SD card to another 2GB card using the dd command (having copied it to the hard drive as an intermediate step).
The original card will load up in the desired device - a TomTom sat nav but the second card won't. Is there any way for me to check that the cards are the same?
Also, and I realise that it's a bit OT here (although the TomTom is a linux device!) but does anybody have any ideas what might be wrong with the card?
ISTR having a similar promble with a Kingston memory stick - it had a separate partition with uselessware in it, and it waas written in a (IIRC) NT format.
Using violent methods under Debian, I deleted the contents of this partition then the partition itself. (It wouldn't go, all in one lump)
After that, the copy worked as per original.
But wouldn't the DD command overwrite everything on the SD card including the partitions?
Strangely, it didn't.
I also tried reformatting it, and it ignored the partition. I think it's because the partition has a different drive address.
On Wed, 2010-08-04 at 17:49 +0100, Anthony Anson wrote:
Chris Walker wrote:
On 04/08/10 17:05, Anthony Anson wrote:
After that, the copy worked as per original.
But wouldn't the DD command overwrite everything on the SD card including the partitions?
Strangely, it didn't.
I also tried reformatting it, and it ignored the partition. I think it's because the partition has a different drive address.
Surely whether dd overwrites the partition table or simply the data in the partition depends on which device file you specify to dd. Generally the device file without a number suffix is the whole device and the one with a number suffix (which is usually the one that is mounted) is a partition.
Also the card must not be mounted, particular if it is the destintation, otherwise filesystem activity may then overwrite the data from dd.
Steve Fosdick wrote:
On Wed, 2010-08-04 at 17:49 +0100, Anthony Anson wrote:
Chris Walker wrote:
On 04/08/10 17:05, Anthony Anson wrote:
After that, the copy worked as per original.
But wouldn't the DD command overwrite everything on the SD card including the partitions?
Strangely, it didn't.
I also tried reformatting it, and it ignored the partition. I think it's because the partition has a different drive address.
Surely whether dd overwrites the partition table or simply the data in the partition depends on which device file you specify to dd. Generally the device file without a number suffix is the whole device and the one with a number suffix (which is usually the one that is mounted) is a partition.
The extra partition on the Kingston drive was hidden - or it thought it was. (I haven't looked at SD cards, but I mentioned the practice as a suggestion for something to look for/at - after all, there's not a lot of difference between a card and a memory stick).
It hung on with its fingernails when I tried to delete it (unwanted guff which only works in Windows anyway) but I now have the full lotsagig to play with.
Also the card must not be mounted, particular if it is the destintation, otherwise filesystem activity may then overwrite the data from dd.
Whether it was mounted or not is a moot point- when the device was plugged in to USB a pane came up asking what I wanted to open it in, and I cancelled the options, so I presume it wasn't mounted.
When viewing the thing in File Mangler it only showed the memory, not the hidden partition with all the insidios^h^h^h^helpful Gatesware on it.
Hooter! Saw it as it was disappearing up the e-flue...
'insidious'!
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Anthony Anson -
Steve Fosdick