Lines Matching +full:read +full:- +full:to +full:- +full:read

14 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 .Nd recover data from disk-like devices.
47 and retries read operations until they succeed.
50 is specified all data read be written there.
52 The internal work-list can be saved and loaded so that
55 source hard-disk shuts down.
57 The work-list is initialized with a single item which covers the entire
61 always chips away at the first item on the work-list.
63 When a read succeeds, that part of the current chunk is eliminated
64 from the work-list.
66 When a read fails, that part of the item is appended to the worklist
72 The first pass attempts to read everything in "big-size" chunks,
73 the second pass reads in "medium-size" chunks and third and subsequent
74 passes read in "small-size" chunks.  This three stage process is
75 an attempt to optimize the case where only a few bad blocks exist
78 If too many read-errors are encountered,
80 will fall back to smaller sizes sooner.
82 The three sizes default to 128kB (or less if the sector size does
91 .Bl -tag -width indent
98 .It Fl r Ar work-list-file
99 Read the work-list from a file.
100 .It Fl w Ar work-list-file
101 Write the work-list to a file when a read succeed, but at most once
103 .It Fl l Ar log-file
104 Each successful read is logged with timestamp, offset and length.
120 this long whenever a read fails.  This makes the
122 device look less sick to the operating system.
124 By default blocks which cannot be read are filled with the pattern
126 in the output file.  This option can be used to specify a different
129 Produce a detailed progress report with ANSI escapes and UTF-8.
137 it may take up to several minutes before the current read operation
141 .Bd -literal
142 # check if all sectors can be read on a USB stick:
151 # read an ISO image from a CD-ROM
155 recoverdisk -r worklist -w worklist /dev/cd0 /data/cd.iso
164 has been used to recover all sorts of data-media for two decades,
166 .Bl -bullet
168 Interacting with failing hardware has a tendency to crash machines,
169 so it is always a good idea to use the
170 .Fl -w work-list-file
171 so that it is possible to continue.
173 When attempting to recover hard to read data from failing hard disks,
174 it pays to pamper the drive as much as possible:
176 It is generally best to keep the drive in it's usual physical orientation,
177 but it can also help to try other orientations.
190 is a problem, use a USB-(S)ATA adapter instead.
194 source code is deliberately written to be easily portable to
197 and to other operating systems.
199 If you need to read ST-506, RLL or ESDI drives
203 Sometimes forcing the disk to step between reads helps.
206 process the work-list in the order it is read, this
207 can be accomplished by sorting the work-list with
213 layer will retry failing read operations, but that
215 and delay recovering what actually can be read from
219 sysctl to zero.
221 For floppies and un-zoned hard disks (ST-506 to
237 because Somebody™ forgot to make a backup copy.
239 .An -nosplit
241 .An Poul-Henning Kamp Aq Mt phk@FreeBSD.org
248 If a failing device causes the machine to crash, there is
249 a risk that a chunk might have been successfully read
250 and removed from the work-list, but not yet flushed to
257 on the destination before writing the work-list to a
259 file before renaming it to the specified
260 .Fl w Ar work-file-list
265 should have an option for reconstructing the work-list