(from Wikipedia)
The
frontside bus is the data path between the CPU and Northbridge. The Northbridge is the part of the chipset that handles data between the CPU, and RAM, among other things.
These days, the Southbridge is taking on more of the role that used to be more exclusive to the Northbridge. So much so that now you can find fans on the North and Southbridge chips, because they got hot like their partner, the CPU. (*"chipset" refers to the combination of the North and South bridge chips).
Some businesses integrate IDE drives alongside SCSI drives; I had a college professor who does networking for a hospital by day, and he said they use both types of drives. The reason is more than needs to be stated here and would be off-point some anyway.
IDE was before PATA and SATA. PATA used parallel data bit travel between the drive, drive controller and data bus. It seemed like the way to go when it first came out, but because some bits would arrive at their destination ever-so-slightly at different "times", the error correction that was needed to put the bits together to make a cohesive chunk of data was slower than it needed to be, so SATA came along (which is serial) and even though data travels in serial form, it actually is quicker than PATA because there is no error correction needed spread out over different bus signals as PATA was.
SCSI was the reigning champ at one time, and is still used a fair amount still. Like SCSI, SATA drives are hotswapable. IDE is not hotswapable, and I believe PATA is not either.
Businesses could (and do) use these different technologies, but usually if you see SCSI in businesses it is in a RAID array.
) answer. and also what is the diff between SCSI & IDE? Is it refering to the cable/ribbon that connects the device to the mobo or is it the device itself? sorry if this is a dumb question I just want to be able to COMPLETELY understand everything you know 
