Version 1.30 of the GNU ddrescue data recovery tool has been released. Notable changes in this release include improvements to automatic recovery of a drive with a dead head, addition of a –no-sweep option to disable reading of skipped areas, and more.

I am pleased to announce the release of GNU ddrescue 1.30.

GNU ddrescue is a data recovery tool. It copies data from one file or block
device to another, trying to rescue the good parts first in case of read
errors. Ddrescue recommends lziprecover[1], whose data recovery capabilities
complement those of ddrescue.

The ddrescue package also includes ddrescuelog, an auxiliary tool that
manipulates ddrescue mapfiles, shows mapfile contents, converts mapfiles
to/from other formats, compares mapfiles, tests rescue status, and can
delete a mapfile if the rescue is done.

The homepage is at http://www.gnu.org/software/ddrescue/ddrescue.html

The sources can be downloaded from http://ftpmirror.gnu.org/ddrescue/
http://download.savannah.gnu.org/releases/ddrescue/ or from your favorite
GNU mirror.

The sha256sum is:
2264622d309d6c87a1cfc19148292b8859a688e9bc02d4702f5cd4f288745542
ddrescue-1.30.tar.lz

This release is also GPG signed. You can download the signature by appending
'.sig' to the URL. If the 'gpg --verify' command fails because you don't
have the required public key, then run one of these commands to import it:

gpg --recv-keys 8FE99503132D7742
wget http://ftpmirror.gnu.org/gnu-keyring.gpg

Key fingerprint = 1D41 C14B 272A 2219 A739  FA4F 8FE9 9503 132D 7742


Changes in version 1.30:

* The changes in this version improve by orders of magnitude the
automatic recovery of a drive with a dead head. For example, all the
recoverable data in a 1 TB drive with one ot its 4 heads dead can now be
recovered after just 283 read errors instead of the 3_782_794 read errors
needed by ddrescue 1.29. (ddrescue 1.29 with the options '--cpass=1,2
--skip-size=32MiB' can recover the data after 880 read errors, but the point
is that an unexperienced user can now achieve results that only an expert
could achieve with the previous version of ddrescue).

* The pass 5 of the copying phase has been replaced by a new sweeping
phase run after the trimming phase.

* The new option '-N, --no-sweep', which disables the reading of skipped
areas, has been added. The short name '-N' has been reassigned from option
'--no-trim' to option '--no-sweep'. Option '--no-trim' is no longer
recommended because trimming has now a higher probability of finding good data.

* Pass 2 now copies only the blocks adjacent to at least one finished
block. The trimming pass now trims only the edges adjacent to a finished
block. The goal is to delimit the bad area as a whole.

* The initial skip size now defaults to 'infile_size / 32_768' instead of
'infile_size / 100_000'.

* '--retrim' now only marks blocks adjacent to a non-tried or finished block.

* '--extend-outfile=0' now extends outfile to the size of infile.

* In rescue mode, '--size=output' now uses the size of the output file or
device, for example to overwrite it:
'ddrescue --force --size=output /dev/urandom /dev/mydisk'.
(Suggested by Stefan Monnier).

* The remaining time is now estimated by using the average rate of the
last 60 seconds instead of the last 30 seconds. (Suggested by Stefan Monnier).

* A line showing 'average rate' and 'read errors' has been added to the
file generated by the event logger.

* Large numbers in option arguments are now accepted with underscore
separators (-s 123_456_789).

* The option '-H, --make-test', which creates a mapfile for the test mode
of ddrescue based on the disc geometry given, has been added to ddrescuelog.
This option has helped in the development of some of the improvements in
this version of ddrescue, and is a work in progress. The geometries
implemented so far are some of those described in the following article:
H. Wong, "Discovering Hard Disk Physical Geometry through
Microbenchmarking", Sept., 2019. Available online at
<http://blog.stuffedcow.net/2019/09/hard-disk-geometry-mic...>

* An example of recovery of a tar.lz backup using a lziprecover-generated
fec recovery record appended to the backup itself has been added to the
manual. (Lziprecover's Forward Error Correction (FEC) algorithm can repair
any kind of file, but its ability to repair lzip files is greater than for
other kinds of files. Lziprecover can use the statistical properties of lzip
data to repair a lzip file rescued with ddrescue, even if the fec file is so
damaged that it has lost both CRC arrays).

(It would be good that lzip were more widely used inside GNU, given its
advantages over gzip for the compression of source tarballs and backups).


Please send bug reports and suggestions to bug-ddrescue@gnu.org

[1] http://www.nongnu.org/lzip/manual/lziprecover_manual.html...

Regards,
Antonio Diaz, GNU ddrescue author and maintainer.
http://www.nongnu.org/lzip/lzip_benchmark.html

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