xref: /freebsd/sbin/recoverdisk/recoverdisk.1 (revision d056fa046c6a91b90cd98165face0e42a33a5173)
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 file
39.Sh DESCRIPTION
40The
41.Nm
42utility reads data from the
43.Pa 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 SIGINT.
62.El
63.Pp
64The
65.Fl r
66and
67.Fl w
68option can be used in combination.
69Especially, they can point to the same file, which will be updated on abort.
70.Sh OUTPUT
71.Nm
72prints several columns, detailing the progress
73.Bl -tag -width remaining
74.It start
75Starting offset of the current block.
76.It size
77Read size of the current block.
78.It len
79Length of the current block.
80.It state
81Is increased for every failed read.
82.It done
83Number of bytes already read.
84.It remaining
85Number of bytes remaining.
86.It % done
87Percent complete.
88.El
89.Sh EXAMPLES
90# recover data from failing hard drive ad3
91.Dl $ touch /data/lots_of_space
92.Dl $ recoverdisk /dev/ad3 /data/lots_of_space
93.Pp
94# clone a hard disk
95.Dl $ recoverdisk /dev/ad3 /dev/ad4
96.Pp
97# read an ISO image from a CD-ROM
98.Dl $ touch /data/cd.iso; recoverdisk /dev/acd0 /data/cd.iso
99.Pp
100# continue reading from a broken CD and update the existing worklist
101.Dl $ recoverdisk -r worklist -w worklist /dev/acd0 /data/cd.iso
102.Pp
103# recover a single file from the unreadable media
104.Dl $ touch file.avi; recoverdisk /cdrom/file.avi file.avi
105.Sh SEE ALSO
106.Xr dd 1
107.Sh HISTORY
108The
109.Nm
110command first appeared in
111.Fx 7.0 .
112.Sh BUGS
113Reading from media where the sectorsize is not a power of 2 will make all
1141 MB reads fail.
115This is due to the DMA reads being split up into blocks of at most 128kB.
116These reads then fail if the sectorsize is not a divisor of 128kB.
117When reading a full raw audio CD, this leads to roughly 700 error messages
118flying by.
119This is harmless.
120.Sh AUTHORS
121.An -nosplit
122The original implementation was done by
123.An Poul-Henning Kamp Aq phk@freebsd.org
124with minor improvements from
125.An Ulrich Sp\(:orlein Aq uspoerlein@gmail.com .
126.Pp
127This manual page was written by
128.An Ulrich Sp\(:orlein Aq uspoerlein@gmail.com .
129