Posted by John Citron on June 20, 19101 at 09:26:42:
In Reply to: number of hard drives posted by Eric Bauman on June 19, 19101 at 03:35:26:
: anyone tell me how many hard drives i can add to a PC?
Eric,
Depends on the type of interface...
1) If it is IDE (EIDE), like most PC systems, you can have two devices per cable. (channel). Most PCs have two IDE channels allowing for up to 4 ide drives. Usually the CD-ROM drive will take a slot, so you can add only three drives.
The drives are configured master and slave on each cable. The recommended practice is to put two
hard disks on one IDE channel (channel 0 or 1 depending on how your MB is marked) and the CD-ROM and other slower devices on the other IDE channel (secondary, channel 1, or 2, again depends on how your m-board is marked). You do this to maximize the performance of your hard drives.
2) SCSI devices allow up to 14 devices on each interface on a newer SCSI-3 controller. The maximum cable length is 18-feet counting all ribbon cables from the controller to the last drive. Each device, including the controller, is given and ID#. The first drive is ID 0, the last is ID15. The controller, on a PC, is usually ID 7 and a bootable drive is ID 0
Older SCSI controllers handled only 6 drives per connector on the controller.
On SCSI based systems there has to be termination of some sort at the ends of the chain. This is supplied through jumpers or soft-settings on the controller. It is best, if capable, to turn on auto-termination on each device this way it can be plugged in without worrying about jumpers or terminators. External devices usually have termination plugs (expensive).
3) Firewire (IEE 1394) I think can handle up to 15 devices.
4) USB maybe more or the same.
I'm most familiar with the traditional IDE and SCSI interfaces.
Don't hesitate to contact me if you have any questions...
John