In version 1.23, the default to not sync every 512 soft blocks is now really
changed to only sync at the end (documented for 1.18, but mostly ineffective,
ouch). More importantly, a short read because of EOF is now not considered an
error any more and thus neither triggers messages (with quiet) nor does it
cause a confusing exit code any more.
Version 1.22 contains a number of little improvements: Display of compiler,
compile time, enabled options, don't repeat copy attempts if hardbs == softbs,
fix FPE in progress bar for non-seekable input reverse copy, and make the code
more digestable for non-GCC compilers, optional fallbacks for strsignal, pread,
pwrite. Last not least, the documentation has a few notes on the goodies now.
Version 1.21 issues warnings when writing in a sparse mode into existing files
or to block devices.
In version 1.20, there's also a progress estimation if input file size is
unknown, but transfer size is limited with -m.
Version 1.19 brings the support for fallocate.
In version 1.18, we have changed the default to -y0 (no fsync), the avg. speed
is calculated in a meaningful way nevertheless now.
In version 1.17, a progress bar, completion percentage and ETA has been added.
In version 1.16, the work was done to determine and display the total amount of
data that will be copied.
Version 1.15 brings support for the Linux splice() mechanism to avoid copying
data to a userspace bugffer.
Changes from 1.12:
The current version is 1.14, released 2007-08-28.
In version 1.14, a bug is fixed that could lead to a target file not having the
correct size when copied in sparse (-a) mode.
In version 1.13, a bug with read-errors and non-seekable output has been fixed.
In version 1.12, the ability to log bad blocks to a ASCII file has been added.
The option -y can be used to set the fsync frequency which can speed up the
copy significantly.
Like dd, dd_rescue does copy data from one file or block device to another.
You can specify file positions (called seek and Skip in dd).
There are several differences:
* dd_rescue does not provide character conversions.
* The command syntax is different. Call dd_rescue -h.
* dd_rescue does not abort on errors on the input file, unless you specify a
maximum error number. Then dd_rescue will abort when this number is
reached.
* dd_rescue does not truncate the output file, unless asked to.
* You can tell dd_rescue to start from the end of a file and move backwards.
* It uses two block sizes, a large (soft) block size and a small (hard) block
size. In case of errors, the size falls back to the small one and is
promoted again after a while without errors.
