xref: /freebsd/sbin/recoverdisk/recoverdisk.1 (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1.\" Copyright (c) 2006 Ulrich Spoerlein <uspoerlein@gmail.com>
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25.\" $FreeBSD$
26.\"
27.Dd May 6, 2006
28.Dt RECOVERDISK 1
29.Os
30.Sh NAME
31.Nm recoverdisk
32.Nd recover data from hard disk or optical media
33.Sh SYNOPSIS
34.Nm
35.Op Fl r Ar rlist
36.Op Fl w Ar wlist
37.Ar special
38.Op Ar file
39.Sh DESCRIPTION
40The
41.Nm
42utility reads data from the
43.Ar special
44file until all blocks could be successfully read.
45It starts reading in multiples of the sector size.
46Whenever a block fails, it is put to the end of the working queue and will be
47read again, possibly with a smaller read size.
48.Pp
49It uses block sizes of roughly 1 MB, 64kB, and the native sector size (usually
50512 bytes).
51These figures are adjusted slightly, for devices whose sectorsize is not a
52power of 2, e.g., audio CDs with a sector size of 2352 bytes.
53.Pp
54The options are as follows:
55.Bl -tag -width indent
56.It Fl r Ar rlist
57Read the list of blocks and block sizes to read from the specified file.
58.It Fl w Ar wlist
59Write the list of remaining blocks to read to the specified file if
60.Nm
61is aborted via
62.Dv SIGINT .
63.El
64.Pp
65The
66.Fl r
67and
68.Fl w
69options can be specified together.
70Especially, they can point to the same file, which will be updated on abort.
71.Sh OUTPUT
72The
73.Nm
74utility
75prints several columns, detailing the progress
76.Bl -tag -width remaining
77.It Va start
78Starting offset of the current block.
79.It Va size
80Read size of the current block.
81.It Va len
82Length of the current block.
83.It Va state
84Is increased for every failed read.
85.It Va done
86Number of bytes already read.
87.It Va remaining
88Number of bytes remaining.
89.It Va "% done"
90Percent complete.
91.El
92.Sh EXAMPLES
93.Bd -literal
94# recover data from failing hard drive ad3
95touch /data/lots_of_space
96recoverdisk /dev/ad3 /data/lots_of_space
97
98# clone a hard disk
99recoverdisk /dev/ad3 /dev/ad4
100
101# read an ISO image from a CD-ROM
102touch /data/cd.iso; recoverdisk /dev/acd0 /data/cd.iso
103
104# continue reading from a broken CD and update the existing worklist
105recoverdisk -r worklist -w worklist /dev/acd0 /data/cd.iso
106
107# recover a single file from the unreadable media
108touch file.avi; recoverdisk /cdrom/file.avi file.avi
109.Ed
110.Sh SEE ALSO
111.Xr dd 1
112.Sh HISTORY
113The
114.Nm
115utility first appeared in
116.Fx 7.0 .
117.Sh AUTHORS
118.An -nosplit
119The original implementation was done by
120.An Poul-Henning Kamp Aq phk@FreeBSD.org
121with minor improvements from
122.An Ulrich Sp\(:orlein Aq uspoerlein@gmail.com .
123.Pp
124This manual page was written by
125.An Ulrich Sp\(:orlein .
126.Sh BUGS
127Reading from media where the sectorsize is not a power of 2 will make all
1281 MB reads fail.
129This is due to the DMA reads being split up into blocks of at most 128kB.
130These reads then fail if the sectorsize is not a divisor of 128kB.
131When reading a full raw audio CD, this leads to roughly 700 error messages
132flying by.
133This is harmless.
134