SCSI - Small Computer Systems Interface
It's much too complicated a topic to discuss in depth, but I can gloss over it.
It's similar to IDE, in that it's an interface used to attach devices to your system, such as hard drives, CD-ROMs, Zip drives, etc. It can also be used for external devices, such as scanners.
It's advantages over IDE are numerous.
* Depending on your adapter, you can hook up anywhere from 7 to 15 devices to a single SCSI controller. IDE is limited to 2 devices per controller.
* Still uses one IRQ per controller, but you can use many more devices on that IRQ compared to IDE.
* Drives can be accessed simultaneously with SCSI, where IDE is limited to one device access at a time.
* Uses less system overhead compared to IDE, since all of the devices are being handled by the controller, not the CPU.
* Increased bus width. Currently, the fastest IDE bus is 100MB/sec, where SCSI currently tops out at 160MB/sec, with 320MB/sec on the way. Since IDE can only use one device per controller at a time, 100MB/sec won't be acheived anytime soon. However, with 7 SCSI drives all working at the same time, 160MB/sec saturation is easily possible.
More info at
www.scsifaq.org <--- READ THIS!!!
The only real disadvantage to SCSI compared to IDE is cost. SCSI devices are usually more expensive than IDE.
One can easily find a 40GB IDE hard drive for around $120, but a decent 36GB SCSI drive will run you upwards of $400.
Despite the advantages of SCSI, the general rule of thumb is: If you don't know why you need SCSI, then you don't need it.
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