1 Mini-Howto for verifying a selfmade CD
3 1) verifying the data layer
5 To verify if all data on the disk can be read,
6 use SCSI verify. This can be done with the
9 use: sformat -verify [target] [lun] [scsibus]
11 If the CD-R device is connected to target 2 on SCSI bus 0
14 sformat can be found on ftp://ftp.berlios.de/pub/sformat
16 NOTE: Not all CD-ROm drives support verifying
17 NOTE: All TAO tracks end in 2 unreadable run-out sectors
19 2) verifying the filesystem layer
21 A quick check is to mount the CD and to use star to read
22 all files on the filesystem.
24 mount -r /dev/cdrom /cdrom (modify for your OS)
26 star -cPM . >/dev/null
28 If no errors can be found, all files are readable.
30 star can be found on ftp://ftp.berlios.de/pub/star
33 You also may want to compare the filesystem on the CD
34 with the original data. This can be done with star too.
37 (cd /master_for_cd; star -cPM .)|(cd /cdrom; star -diff -v)
39 2a) verifying the iso image before creating the CD
41 You may check the filesystem image by mounting it with my
42 "fbk" on Solaris or the loopback driver on Linux.
45 mount isoimage.raw -r -t iso9660 -o loop /mnt
48 mount -r -F fbk -o type=hsfs /dev/fbk0:isoimage.raw /mnt
50 For Solaris 8 and later you may also use the Sun lofi driver (see README.sun-lofi)
52 The check the filesystem with:
54 (cd /master_for_cd; star -cPM .)|(cd /mnt; star -diff -v)
57 Solaris has a bug with hardlinks. It generates different inode numbers
58 for the hardlinks to a file. This makes it impossible for star to
61 (cd /master_for_cd; star -cPM .)|(cd /cdrom; star -diff -v diffopts=!hardlink)
65 NOTE: Some operating systems have a read ahead bug that causes I/O errors for
66 the last file(s) on a CD. This seems at least to be true for all Linux versions
67 and for Solaris 7 FCS. For Solaris 7 there is a patch (107465-02) that you should
68 install. This I/O error problem does not occur with DAO disks and with TAO disks
69 that have been written with wodim -pad.
73 Source: README.verify from cdrtools package
74 Edited for cdrkit by Christian Fromme <kaner@strace.org> and Eduard Bloch