You shouldn't use DOS syntax directories with dd!! The directory syntax is like with linux. Where did you even get the idea of using such a syntax! Try at least trying to follow a guide of some sort!
This command worked for me for example. (Done from an administrative cmd prompt), and you can change -b 1M
to -b 4M
(you have 4M, perhaps the latter is faster, but I found 1M fine)
(ok i'm using ddrescue (a gnu package, and is actually better than dd), but the way i've specified the partition, in contrast to how you have, applies to dd too)
$ ddrescue -r3 -b 1M -d /dev/sdb /cygdrive/c/crp/fsfwr_.fc
Cygwin is more awkward than linux when it comes to showing what is mounted where
You can look at /dev and do things like $ cygpath -w sdb1
and it might say e.g.
\\.\F:
And this crazy command a linux wiz showed me for use in cygwin, automates the cygpath -w commands, and can give you a list of what is moutned where
for F in $(gawk '{if (FNR > 2) print "/dev/" $4;}' /proc/partitions) ; do echo "$F $(cygpath -w $F)" ; done
it then shows like
/dev/sda \\.\PhysicalDrive0
/dev/sda1 \\.\Volume{b6ef2ec3-451e-11e2-822b-806e6f6e6963}
/dev/sda2 \\.\C:
/dev/sdb \\.\PhysicalDrive1
/dev/sdb1 \\.\F:
/dev/sdc \\.\PhysicalDrive2
/dev/sdc1 \\.\G:
/dev/sdc2 \\.\Volume{b6ef2ec3-451e-11e2-822b-806e6f6e6963}5
so the syntax for your dd line would be like this below, though might not be sdb1, but you can run that command above to see which /dev to use.
dd if=/dev/sdb1 of=/cygdrive/k/backup_sd_card.img bs=4M
1
dd
is used to copy disks by their disk identifier, NOT their mounted folders. The problem with using folders is that the folder represents the data of the disk in a certain format - this can be different based on the filesystem, and doesn't encompass all of the data, for e.g. file indeces. When dd copies a disk, it copies the exact sectors bit-for-bit, regardless of the folders/file structure or filesystem. You need to find how the disks are seen inside cygwin. You may not be able to access the disk as a device (as you would in Linux under /dev/sdXX) if its being handled by Windows. – QuickishFM – 2019-01-20T15:59:02.787ouch. you shouldn't be using DOS syntax directories with dd!! The directory syntax is like with linux. Where did you even get the idea of using such a syntax! Try at least trying to follow a guide of some sort! – barlop – 2019-01-20T16:02:23.263
To be clear I am using conemu terminal but binary 'dd' if from cygwin. I am using syntax like at this article http://realinfosec.com/?tag=how-to-use-dd-on-windows . Disk is seen by mountvol as ?Volumeab627f51-f12b-11e7-bc1b-e277073b2b9d\ . Do I still need to search disk signatures under cygwin?
– lluke – 2019-01-20T16:20:36.867