When imaging to a device with verification under Mac OS X, verification
can fail due to automatic mounting of the target device. One solution is
to use Disk Arbitrator in conjunction with dc3dd on OS X.
Log output may be sent to multiple job logs and hash logs. Simply specify
log=LOG and/or hlog=LOG more than once.
Verification of an image restored to a device larger than the image is now
supported. Specify hof=DEVICE to hash only the bytes dc3dd writes to the
device. Specify fhod=DEVICE to hash both the bytes dc3dd writes to the
device and all the bytes that follow, up to the end of the device.
Specifying hof=DEVICE will now default to phod=DEVICE behavior (hash only
the bytes output by dc3dd, not the full device).
dc3dd is distributed as source code and must be compiled before use.
The default configuration can be built and installed to /usr/local/bin
with the following commands:
$ tar zxvf dc3dd-7.2.640.tar.gz
$ cd dc3dd-7.2.640
$ sudo make install
Note that autoconf-1.10.1 and gperf may need to be installed prior to
execution of the above commands.
dc3dd can be customized at compile-time with various options.
The available options are as follows, and can be verified after
compilation using the --flags command line option:
(equivalent to hash=md5 command-line option)
(equivalent to hash=sha1 command-line option)
(equivalent to hash=sha256 command-line option)
(equivalent to hash=sha512 command-line option)
(equivalent to ofsz=BYTES command-line option)
(equivalent to verb=on command-line option)
(equivalent to nwspc=on command-line option)
(equivalent to dbr=on command-line option)
Enable checking ATA/SATA drives for hidden areas
No command-line equivalent, cannot be overridden.
These options are enabled by including them in the CFLAGS argument to
configure. For example, to enable MD5 hashing and default output file
$ ./configure CFLAGS="-O2 -DDEFAULT_HASH_MD5
The program can be statically linked by adding "-static" to the CFLAGS
$ ./configure CFLAGS="-O2 -static"
Mac OS X:
To enable error recovery, use /dev/rdisk* instead of /dev/disk*
dc3dd can be compiled using Cygwin, but bad sectors can put the program
into an infinite loop due to bugs in Cygwin.
Please send all correspondence to: firstname.lastname@example.org