Messages in this thread | | | From | "Robert A. Morris" <> | Subject | ISSUE: Files missing when recursively listing an ISO9660 CD-ROM | Date | Sun, 25 Jul 1999 23:53:47 -0400 |
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ISSUE: Files missing when recursively listing an ISO9660 CD-ROM
DESCRIPTION: When doing a recursive listing of all files on an ISO9660 CD-ROM, or when using the find command to execute the md5sum command on all files on such a CD-ROM, inconsistent results are returned. Running the following sequence of commands several times consecutively on the same disc (with or without ejecting it) generates listings of files which semi-randomly (more on this below) omit files, without generating errors in /var/log/messages or dmesg:
cd /tmp mount /mnt/cdrom ls -lR /mnt/cdrom > filename.ext umount /mnt/cdrom
In the above case, specify a different output filename each time and run duff-u between pairs of listings. Files present in some are missing in others. The next sequence behaves similarly:
cd /tmp mount /mnt/cdrom find /mnt/$1/* -noleaf -type f -exec md5sum {} \; > filename.ext umount /mnt/cdrom
Copies of some output from the above available on request.
The above two sequences are useful in verifying copies of CD-ROMs made with a CD recorder, but the effect is reproducible on both the original discs and the copies. Only discs from certain commercial programs seem to be affected, notably Microsoft Office 2000 Standard Upgrade, Microsoft Windows 98 Upgrade, and Calendar Creator 5.0. Many others are not, however.
If the disc is not unmounted and then remounted between consecutive executions of the ls or find commands, the results are always exactly consistent.
The files which are missing seem to usually be from the same directories, but the exact files affected seem to differ. Certain directories seem to be prone to missing files on a given disc, but the results are not consistent. Files missing vary in length from 200 bytes to 7 MB, and directories contain from 34 to 167 files.
Different original copies of the same disc show similar errors - it's not just the one disc that I happen to be using. It's also not just my hardware - the problem is reproducible on my /dev/hdb ATAPI Creative CD4830E and my /dev/scd0 Smart & Friendly CD-R2006 Plus which uses a Future Domain TMC-3260 SCSI controller. Both of the above are attached to an AMD K6-III-450 running on a TYAN S1590S motherboard (VIA MVP3 chipset). It is also happening with an identical CD4830E ATAPI CD-ROM which is /dev/hdb on a Pentium-MMX 233 with Biostar 8500TTD motherboard (Intel 82439TX chipset). Kernel version in both cases is 2.2.10. The VIA machine uses the VIA 82C586 driver. IDE and SCSI drivers are compiled into the kernel, and the kernel is compiled on a RedHat 6.0 system (glibc-2.1).
Keywords: iso9660, cdrom, atapi, ide, scsi, via, vfs, 2.2.10
Detailed kernel-provided hardware and software information follows, for the AMD K6-III machine:
/pro/cpuinfo: processor : 0 vendor_id : AuthenticAMD cpu family : 5 model : 9 model name : AMD-K6(tm) 3D+ Processor stepping : 1 cpu MHz : 451.030741 fdiv_bug : no hlt_bug : no sep_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr mce cx8 sep mtrr pge mmx 3dnow bogomips : 897.84
/proc/scsi/scsi:Attached devices: Host: scsi0 Channel: 00 Id: 06 Lun: 00 Vendor: SAF Model: CD-R2006PLUS Rev: 2.05 Type: CD-ROM ANSI SCSI revision: 02 Host: scsi1 Channel: 00 Id: 06 Lun: 00 Vendor: IOMEGA Model: ZIP 100 Rev: J.03 Type: Direct-Access ANSI SCSI revision: 02
/proc/ide/drivers: ide-cdrom version 4.53 ide-disk version 1.08
/proc/ide/ide0/config: pci bus 00 device 39 vid 1106 did 0571 channel 0 06 11 71 05 07 00 80 02 06 8a 01 01 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0b f2 09 ba 68 13 f0 00 a8 21 31 21 ff 00 ff ff 03 61 03 61 00 00 00 00 a8 a8 a8 a8 00 00 00 00 00 02 00 00 00 00 00 00 00 02 00 00 00 00 00 00 02 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00 00 40 09 00 00 00 00 00 00 48 09 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 06 00 71 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
/proc/ide/ide0/mate: ide1
/proc/ide/ide0/model: pci
/proc/ide/ide0/hdb/*: capacity: 2147483647 driver: ide-cdrom version 4.53 identify: 85a0 0000 0000 0000 0000 0000 0000 0000 0000 0000 2020 2020 2020 2020 2020 2020 2020 2020 2020 2020 0000 0000 0000 5532 3043 2020 2020 4372 6561 7469 7665 2043 4434 3833 3045 2020 2020 2020 2020 2020 2020 2020 2020 2020 2020 2020 2020 0000 0000 0f00 0000 0400 0200 0002 0000 0000 0000 0000 0000 0000 0000 0000 0000 0107 0003 0078 0096 00e3 0078 0000 0000 0000 0000 0002 0009 3030 3330 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
media: cdrom model: Creative CD4830E settings: name value min max mode ---- ----- --- --- ---- breada_readahead 4 0 127 rw dsc_overlap 1 0 1 rw file_readahead 72 0 2097151 rw io_32bit 0 0 3 rw keepsettings 0 0 1 rw max_kb_per_request 122 1 127 rw nice1 1 0 1 rw pio_mode write-only 0 255 w slow 0 0 1 rw unmaskirq 0 0 1 rw using_dma 0 0 1 rw
/proc/filesystems: ext2 umsdos msdos vfat nodev proc nodev nfs nodev smbfs iso9660 ntfs hfs nodev autofs nodev devpts
/proc/version: Linux version 2.2.10 (root@dilithium.mit.edu) (gcc version egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)) #1 Sun Jul 25 06:06:28 EDT 1999
software: Kernel modules 2.1.121 Gnu C egcs-2.91.66 Binutils 2.9.1.0.23 Linux C Library 1.1.so Procps 2.0.2 Mount 2.9o Net-tools (1999-04-20) Sh-utils 1.16
-- Robert A. Morris <ramorris@mit.edu> Home Page: http://web.mit.edu/ramorris/www/ PGP Key: http://web.mit.edu/ramorris/www/key.txt ICQ UIN: 38290261
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