[NTLUG:Discuss] SCSI drives

[Greg Edwards]

Vaidya, Harshal (Cognizant) wrote:
> Hi All,
> 
>   Can anybody explain me what is the difference between a normal Hard Drive
> and SCSI drive.
> 
> Thanks and Regards,
> Harshal Vaidya

The short answer.

SCSI is traditionally faster and more efficient than IDE.  Recently IDE 
has narrowed the gap in performance but still has some design issues 
that cannot overcome the performance advantages of SCSI.  You usually 
won't find PC motherboards with onboard SCSI controllers so you need a 
card (PCI) to use SCSI drives in a PC.

One major advantage to SCSI is that a single controller can chain 
anywhere from 7 to 15 SCSI devices (inside or outside the case) together 
while IDE can only chain 2 (inside the case only) together.  IDE can 
only handle disks while SCSI can handle any device type.  SCSI allows 
each device to transfer independently so that each device can transfer 
data concurrently.  In general IDE is forced to run at the transfer rate 
of the slowest device in the physical chain while SCSI can transfer at 
different rates to different devices on the same chain.

A major disadvantage to SCSI vs IDE is the $$$$.

MadHat gave you some good links for the long answer.

Good luck,
-- 
Greg Edwards
New Age Software, Inc.
http://www.nas-inet.com