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The pass 5 of the copying phase has been replaced by a new sweeping phase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-microbenchmarking/>

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 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).
