CompuServe Thread

#Bad disc – why?

2 messages in this thread
#48994From: Kevin O'NealMay 22, 1993 4:51 PM
I had a problem with some CD-ROM discs. I found two discs that failed to work properly on my machine. In one case, my PC would read the directory and some of the files, but could not read the vast majority of the files on the disc. In the other case, my machine could read the directory, but could not access any of the files. Both discs came from the same vendor and the same mastering plant. My PC is a 33-MHz 386. The CD-ROM drive is the Mitsumi 002 with the eight-bit interface card, using the software driver, not the DMA interface. All of my other CD-ROMs work perfectly in this drive. I'm curious to learn exactly what causes a disc to fail? Is there something with the interleaving or encoding of the data that stops a drive from being able to read the information on a disc? I've wondered about what leads to a bad disc, but no one seems to know the answer. In the same area, I've never been able to figure out why switching motherboards improved the performance of my Mitsumi drive, especially since I reused all of the components from the previous setup, including the SIMMS, CPU and expansion cards.
#49073From: David Dillard [MDI]May 24, 1993 9:59 AM
"what causes a disc to fail?" One time we ran across a NASA disc that had some files that couldn't be read. We did some low-level investigation and found that the directory entries for the files we couldn't read were off the end of the disc. We called the publisher and after a little while they figured out that they "hadn't loaded the last tape". David