Re: Re: unable to read some of a DVD contents
Yes. as Thomas and Volker pointed that the media is the one to be blamed. I used better quality DVD, the most expensive one in the store :), and I've 5 successful burns and all passed the integrity check. Thanks for all your helps, Kadir --- This email contains confidential information. If you have received this email in error, please delete it immediately, and inform us of the mistake by return email. Any form of reproduction, or further dissemination of this email is strictly prohibited. Also, note that the opinions expressed in this email are those of the author and are not necessarily those of the Fonterra Co-operative Group Limited. http://www.fonterra.com/ ---
Re: unable to read some of a DVD contents
Hi, > As you mentioned, neither the burner nor the media > is the one to blame so what > is the thing that causes the test checksum to fail? In this case the individual media is to blame. At least in conjunction with my burner device. The annoying problem with DVD burning is that it is so hard to predict wether an individual combination of burner and media will work flawlessly. So, in case of trouble, one will most often get the advice to either use other media or upgrade the drive's firmware. Of course, this is the expression of pure helplessness. We are poking in the mist by help of very long sticks. > Does that cause by the "on-the-fly" burn using growisofs? It should not. (But who knows for sure ?) Modern burners are protected against buffer underrun which used to be the main problem of burning on-the-fly with old CD recorders. Up to now i could not find a correlation between obvious slowdowns of the feeding data stream and failure to checkread the resulting media. Have a nice day :) Thomas -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: unable to read some of a DVD contents
> >The sucessfull DVD-RW is in heavy test use, has a nice collection of scratches ... and it works fine. The ill one had its third or fourth re-use, looks shiny and smooth ... > As you mentioned, neither the burner nor the media is the one to blame > so what is the thing that causes the test checksum to fail? Yes the media *is* to blame. You always get some faulty ones more or less randomly (that's why he said it wasn't the whole lot which was shot). > Does that > cause by the "on-the-fly" burn using growisofs? Definitely not. Volker -- Volker Kuhlmann is possibly list0570 with the domain in header http://volker.dnsalias.net/ Please do not CC list postings to me. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: unable to read some of a DVD contents
>I just had to trash a previously used DVD-RW which failed to pass the checksum >test with errors at the very start of the image. >After a test re-write it failed to deliver the last 2 MB (but the start of the >test image was ok). >A third re-write yielded missing 300 MB at the end of the media. The fourth >try failed with :-[ PERFORM OPC failed with SK=3h/ASC=73h/ACQ=03h]: >Input/output error According to keys.txt : 3 73 03 POWER CALIBRATION AREA >ERROR (Not much idea what that means but it looks ugly and fatal) >I successfully tested another DVD-RW from the same spindle as the ill one. So >the burner is not to blame. >It is not about the manufacturer of the media, not even about the particular >lot. It is not about the number of re-uses. >The sucessfull DVD-RW is in heavy test use, has a nice collection of scratches >... and it works fine. The ill one had its third or fourth re-use, looks shiny >and smooth ... As you mentioned, neither the burner nor the media is the one to blame so what is the thing that causes the test checksum to fail? Does that cause by the "on-the-fly" burn using growisofs? Thanks, Kadir --- This email contains confidential information. If you have received this email in error, please delete it immediately, and inform us of the mistake by return email. Any form of reproduction, or further dissemination of this email is strictly prohibited. Also, note that the opinions expressed in this email are those of the author and are not necessarily those of the Fonterra Co-operative Group Limited. http://www.fonterra.com/ ---
Re: unable to read some of a DVD contents
Hi, >> - or to compare the data image on DVD with a checksum > > which was made when that image was written to DVD. > > First time heard about this method. How to actually obtain the DVD checksum? If you got the image stored on disk you may use program md5sum. If you generate and burn the image on-the-fly compute the checksum by a pipe filter. With bash there is a trick called "Process Substitution" which would allow to do that by md5sum, too. On Aug 25 2004, Robert Schiele wrote regarding a related topic : : On bash you can do simply: : $ mkisofs ... | tee >(md5sum) | cdrecord Ok, it's not that simple but it shows a path. You will have to record the output of md5sum as well as the exact size of the image. The size is important since you will hardly get an exact EOF from DVD or CD. At least with CD you need to pad about 300 kB after the the checksumed image to ensure that the image can be completely read. (DVD unsure) So you would need a script which invokes md5sum, counts the bytes and records them in some kind of database. Best is if the checksum gets appended to the image on DVD, too. In my own project i use a C language program for that. So i do not have to rely on exotic >(...) gestures. This also allows additional stunts. For details see http://scdbackup.webframe.org/README search for "Verifying CDs and DVDs" and "Appendix VERIFY". See also http://scdbackup.webframe.org/cd_backup_planer_help for details about some options mentioned in README. > Will this method run faster than the first one? > (We normally have around 1 files to compare). It should not be slower. It avoids directory lookups and random access movements. On my system reading begins with about 4.8 MB/s and accelerates up to 10 MB/s while computing uses up 30% of an AMD 2600+. A full DVD verify of 4.7e bytes lasts about 10 minutes if the media is ok. Damaged media are often quite slow. > Brief explanation on this method will be appreciated (keen to try this out). To make it brief would be serious work ;-) > How did you know there was 300MB data missing at the end of media? > In our case, the file sizes exactly match the file sizes on the harddrive. Those sizes are read from the ISO filesystem directory which is located at the beginning of the disk. That part of your DVD seems to be ok. But it refers to data areas which seem to be damaged. The missing size was detectable because my checksum records contain the size measurement from writing. In my role as developer of backup software i am looking for trouble. Therefore i not only compute a single checksum for the whole backup but one for each 64 kB of data. So i can recognize wether the damage forms single spots or wether it hits wide areas. (For details see README, Appendix REDUNDANCY) > >:-[ PERFORM OPC failed with SK=3h/ASC=73h/ACQ=03h]: Input/output error > Got this problem before upgrading growisofs. Well, i'm on 5.21. No newer version known. Also, the problem is restricted to a single disk. I'll try cdrecord-ProDVD on it next. It's just for illustration how important a trustworthy checkread is. Have a nice day :) Thomas -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: unable to read some of a DVD contents
Thanks for the comprehensive explanation, > Hi, > > > what is the indicator that the burn process was only 95% completed? > > The only reliable indicator seems to be checkreading > by all drives which shall be able to read the DVD. > > This would mean either > > - to compare each file on the DVD with its original > on hard disk (if the files on disk did not change > meanwhile) This is the method we used (comparing each file on the DVD with its orginal on hard drive by using 'cmp' command) > > - or to compare the data image on DVD with the data > image on disk (if the image was stored on disk) > > - or to compare the data image on DVD with a checksum > which was made when that image was written to DVD. > (I prefer this method.) First time heard about this method. How to actually obtain the DVD checksum? Will this method run faster than the first one? (We normally have around 1 files to compare). Brief explanation on this method will be appreciated (keen to try this out). > > > I just had to trash a previously used DVD-RW which > failed to pass the checksum test with errors at the > very start of the image. After a test re-write it > failed to deliver the last 2 MB (but the start of the > test image was ok). A third re-write yielded missing > 300 MB at the end of the media. How did you know there was 300MB data missing at the end of media? In our case, the file sizes exactly match the file sizes on the harddrive. > The fourth try failed with >:-[ PERFORM OPC failed with SK=3h/ASC=73h/ACQ=03h]: Input/output error > According to keys.txt : >3 73 03 POWER CALIBRATION AREA ERROR > (Not much idea what that means but it looks ugly and fatal) > Got this problem before upgrading growisofs. > I successfully tested another DVD-RW from the same > spindle as the ill one. So the burner is not to blame. > > It is not about the manufacturer of the media, not even > about the particular lot. It is not about the number of > re-uses. The sucessfull DVD-RW is in heavy test use, has > a nice collection of scratches ... and it works fine. > The ill one had its third or fourth re-use, looks shiny > and smooth ... > > > Have a nice day :) > > Thomas > Thanks, Kadir -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: Re: unable to read some of a DVD contents
Hi, > what is the indicator that the burn process was only 95% completed? The only reliable indicator seems to be checkreading by all drives which shall be able to read the DVD. This would mean either - to compare each file on the DVD with its original on hard disk (if the files on disk did not change meanwhile) - or to compare the data image on DVD with the data image on disk (if the image was stored on disk) - or to compare the data image on DVD with a checksum which was made when that image was written to DVD. (I prefer this method.) I just had to trash a previously used DVD-RW which failed to pass the checksum test with errors at the very start of the image. After a test re-write it failed to deliver the last 2 MB (but the start of the test image was ok). A third re-write yielded missing 300 MB at the end of the media. The fourth try failed with :-[ PERFORM OPC failed with SK=3h/ASC=73h/ACQ=03h]: Input/output error According to keys.txt : 3 73 03 POWER CALIBRATION AREA ERROR (Not much idea what that means but it looks ugly and fatal) I successfully tested another DVD-RW from the same spindle as the ill one. So the burner is not to blame. It is not about the manufacturer of the media, not even about the particular lot. It is not about the number of re-uses. The sucessfull DVD-RW is in heavy test use, has a nice collection of scratches ... and it works fine. The ill one had its third or fourth re-use, looks shiny and smooth ... A theory which emphasizes the influence of moon phases or geomantic radiation would probably be as successful as the usual methods of DVD compatibilty prediction. Have a nice day :) Thomas -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: Re: unable to read some of a DVD contents
> I used verbose option and clearly see that the burn process was completed and > the session was closed. > what is the indicator that the burn process was only 95% completed? The burn was 100% completed at 95% quality. ;) That's putting it colloquially of course. The burner is maladjusted to the media, when all remaining tolerance for successful reading is exceeded, you get a read error. What this really indicates however that the whole process is very marginal with no space for future errors left. Dump those disks, or at least don't expect them to still hold your precious data in a few months. And even if they still work in a few months, don't trust it. Volker -- Volker Kuhlmann is possibly list0570 with the domain in header http://volker.dnsalias.net/ Please do not CC list postings to me. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: Re: unable to read some of a DVD contents
>>I've successfully burnt data (4 GB, around 1 files) to a DVD. >>I saw that all the files have been burnt to DVD with exact size.>>However, I couldn't read some of the files (corrupted ?) and this happened randomly (i.e. I burnt another ten DVDs with the same contents and the corruptions >>happened on different files).>A clear indication that you did *not* burn succesfully (only 95%>succesfully - as you see that's not good enough), or that the reader is>unable to read the burnt disk. Media incompatability in both cases, the>drive(s) can't adjust to the inserted media correctly. Try a different>media brand.>Volker I used verbose option and clearly see that the burn process was completed and the session was closed. what is the indicator that the burn process was only 95% completed? I'll definitely try your suggestion with a different media brand. thanks, Kadir
Re: unable to read some of a DVD contents
> I've successfully burnt data (4 GB, around 1 files) to a DVD. > I saw that all the files have been burnt to DVD with exact size. > However, I couldn't read some of the files (corrupted ?) and this happened > randomly (i.e. I burnt another ten DVDs with the same contents and the > corruptions happened on different files). A clear indication that you did *not* burn succesfully (only 95% succesfully - as you see that's not good enough), or that the reader is unable to read the burnt disk. Media incompatability in both cases, the drive(s) can't adjust to the inserted media correctly. Try a different media brand. Volker -- Volker Kuhlmann is possibly list0570 with the domain in header http://volker.dnsalias.net/ Please do not CC list postings to me. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
