Hey, you cannot make a copy using a CD drive!
The only way is to get a double-crossed Ethernet cable OR modified parralel cable and connect it to your Dreamcast.
Using parallel cable it can take up to 24 hours!!!
Using Ethernet it can take up to 1 hour!!!!
Of course you need a network card (preferably 10/100Mbit and CAT5 cable)
For A LOT of information about Dreamcast copying, give www.consolecopyworld.com a visit!
Of course, you can also download a Dreamcast rip from the Net.
To make one yourself, it will take you a lot of time and quite a bit of technical knowhow!!!