“I’ve got two HD’s, a CD-ROM and a CD-RW running on a UDMA/66 IDE main-board. One HD is rather old, and currently is composed of two 3gig partitions. This drive holds the OS, programs, etc. the other drive is a 7200 rpm 60 gig drive that will be used solely for recording.
Which drives should be masters and which should be slaves for optimum audio performance? Which drives should be slaved to each master?”
The following is the most effective way – for BOTH PC and Mac – to configure an IDE drive system consisting of 2 hard drives and 2 optical drives:
IDE Bus 0:
MASTER = Original HD w/ OS on it
SLAVE = Audio HD
IDE Bus 1:
MASTER = CD-ROM Drive
SLAVE = CD-R/W
The standard configuration is to place the hard drive(s) on the primary channel and the CD-ROM(s) on the secondary IDE channel.
PC users should make sure that UDMA is enabled. In the case of both Mac and PC, if the system [or “old”, in this case] HD isn’t UDMA-capable, DO NOT use it on the same channel as a drive that is (a.k.a. your audio drive, presumably). See the “best solution” below.
That being said, avoid the use of slave drives if at all possible. Every drive, be it a hard drive or some other form of storage media, runs faster and more efficiently if it doesn’t have to fight another drive for bandwidth.
In any case, for performance reasons, it is better to avoid mixing slower and faster devices on the same bus. If you absolutely have to share a bus between a hard disk and an optical (or other ATAPI) device, it is generally a good idea to make the hard disk the master. We say generally because if the drive is very old (say 3+ years), there’s a good chance that the optical drive may be as fast, or faster – if the optical drive is a new drive itself, that is. Otherwise, there can be problems slaving a hard disk to an optical drive; it will usually work but it is not recommended (never do it if the drive in question is your system drive). Since there is no advantage to making the ATAPI device the master, the configuration is best avoided.
There are several reasons why optical drives (or other ATAPI devices) should not be shared on the same channel as a fast (UDMA capable) hard disk. ATAPI allows the use of the same physical channels as IDE/ATA, but it is not the same protocol; ATAPI uses a much more complicated command structure. Opticals are also generally much slower devices than hard disks, so they can slow a hard disk down when sharing a bus. Finally, some ATAPI devices cannot deal with DMA bus mastering drivers, and will cause a problem if you try to enable bus mastering for a hard disk on a bus they are using.
So what is the BEST solution? If you have an extra PCI slot available, buy a PCI IDE adapter card (about $100) so you can add another two IDE busses to your system. That way you can run all four drives on separate busses (because this is an all-important DRIVE bus, you should use it in your first PCI slot, if possible).
And your audio drive wants its own bus. Seriously.