> I am getting the following message when I attempt to copy a file from a CD > to my Linux box. > > cp: reading '/mnt/cdrom/unix/data/data.taz': Input/Output error
Ew, that looks bad. I/O errors are reported by the operating system to programs calling the read() system call. Application programs doesn't really have anything they can do about this. The operating system handles the reading from the device. If the OS can't read the device then it reports an error to the application and the application reports it to you. Errors during read are usually indications of bad spots on the media. If this failure was on your hard drive I would say backup what you could quick because your hard drive is dying. But since this is on a CD which is "removable media" it is only a temporary condition for the device. But it might be permanent for the media if it has a corrupted data section. On a CD that usually means surface damage. But it may also be corrupted bits even on a new and unused CD. Mass produced CDs are mechanically pressed into the surface. (Which I still find amazing.) In recent years the reliability has been really good. But when CD's were introduced up to 30% of them had defects. This was only acceptable because in music that error will not be noticed by your ear. > We are running Redhat v. 7.2, and the file I'm trying to copy is about > 10.5MB in size. I'm wondering if this is a size limitation of some sort. The GNU cp program can copy files up to the filesystem size limits. On many systems this is up in the hundreds of gigabyte range. > We've tried this on several CD's so that variable is eliminated. Finally, I > reduced the file size to about 6MB, and it copied without any > problems. How do you reduce the size of a file on a CD? > Can you provide me some information on why I would be getting this > message? The only other factor we can consider is hardware. All > other files (.taz) on the CD copy without a problem. It is possible that the data in that file on that particular CD is has bad spots due to scratches or other physical damage to the CD. If it appears near the end of the file then that would explain why you can copy the first 6MB of data. Just for data gathering, try using other programs. Here are a selection. Note that I expect these all to fail the same way as cp fails since they are just calling the os read routine. cat /mnt/cdrom/unix/data/data.taz > /tmp/data.taz dd if=/mnt/cdrom/unix/data/data.taz of=/tmp/data.taz bs=32k If it is just a bad spot on the CD but you actually get it read once then save it because you will have your data. You don't want to lose it by overwriting it with another command. Some CD readers work better than others at reading troubled CDs. But I think that is what you meant when you said you had tried difference CDs already. Bob _______________________________________________ Bug-fileutils mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/bug-fileutils
