I've got a G3 mac (450) and a scsi hard drive for running DP. I want to add a new drive for the operating system and use the scsi exclusively for for recording. Can I use an EIDE drive (cheaper) for the operating system or will this slow me down? Also they have firewire drives but I have my 2408 hooked to the computer with that, will that slow things down as well? Also do firewire drives have the throughput that scsi's have?

Ideally you'd put your operating system on a scsi drive, but today's IDE drives are faster than ever and have equivalent thoughput as some of the older scsi-2 drives. This should'nt really affect your recording throughput if you use seperate drives for your audio data. One thing to remember is that your scsi bus is as fast as the slowest device on it's chain.

There was a recent thread which was about CD burners that talked a lot about what the advantages were to the different kind of drives for Macs. I found it quite informative. Do a search for it and check it out.