Re: system slowdown when copying audio CDs
On Tue, 13 Mar 2001, Romain Lerallut wrote:
> Funny that the behavior of the CD drive is so different in the audio
> mode than in the data mode.
It isn't really. Data CD's contain data headers that help the drive
position itself in arbitrary locations - similar to sector headers on
floppy and hard disks. Audio CD's contain only vague information. They
aren't designed to seek so precisely. Furthermore audio CD sectors are a
different size from data CD sectors.
When you try to seek somewhere on an audio CD, you can rig the CDROM to do
it, but you will not have the required information to "aim" precisely.
And, you can read only a few sectors at a time. With a data CD you can
tell the CDROM drive which blocks you want and it will just go get
them. With an audio CD, you give it coordinates on the disk, it will go
somewhere in that area and return a few blocks. Then you have some small
amount of time to get the next read request in before the drive loses its
"place" and you have to start the whole seek process over again.
All in all it is very difficult to treat audio CD's as data and this is
why CD rippers are so hard to write (and so slow).
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