#Bad disc – why?
2 messages in this thread
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.
"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