SCSI  v/s EIDE

*** Note: essay under construction... ***

     So, you were looking through one of those hardware catalogs and saw a SCSI drive for a little more than the average IDE and you're asking yourself what the big deal is.  Heck, you are wondering if it's worth the bother.  I can say with all of my heart a resounding...  depends.

IDE's advantages:

    Simply put, most moderm motherboards come with an on-board IDE controller.  Generally, they are fairly intuitive in the realm of auto detection with more modern IDE drives.  They are virutally plug and play devices with the exception of a jumper defining wether you want the drive to be a 'master' (primary device on the IDE chain) or a 'slave' (secondary device).  The other advantage is that you get two of these controllers for all of your computing needs.  For most folks, this is adequate.  You can drop in a maximum of three hard drives and a CD-ROM for a big chunk of storage space and you get to run all of your favorite CDs as well.  Not bad.

SCSI is here!

     Actually, SCSI has been around for quite some time.  I've got somewhere a small article describing one of the earlier standards.  SCSI allows you to place a maximum of seven devices on a chain.  (Technically, it is eight, but the SCSI controller/host adapter is counted in that number.)  SCSI has a variety of standards and is not limited to supporting just hard drives and CD-ROMs.  For example, DAT tape drives, removable hard drives (such as IOmega's Zip and Jaz drives), CD-ROM burners, and I'm fairly sure some scanners.

     While I'm sure the above devices I listed may exist in some form using an IDE controller or some alternate means to SCSI.  There is one other thing that gives SCSI a superior edge: data throughput.  On average, (I'm working from memory so, if someone has hard info to prove otherwise...) IDE has a throughput of about 3 to 4 MB/sec. (MegaBytes per second) and an optimum throughput of about 6 MB/sec.  SCSI on the other hand has an average throughput of 5 to 6 MB/sec. and an optimum throughput of 10MB/sec.  I think you get the picture.

Flavors of SCSI...

     SCSI comes in a number of flavors.  The most common is SCSI 1 and SCSI 2.  This is the most economical standard out there.  There is also SCSI 3 which (I think) is also referred to as wide SCSI, which has an optimum throughput of 20 MB/sec..  The downside is, that I don't think you can mix SCSI 1 and 2 devices with SCSI 3 devices.  There is also another standard out there known as RAID.  I'm not familiar with it, but it's primary application tends to be for heavy server applications.  In other words, even for a disk-intensive home/small business application it's more power than you will ever need.  Since my familiarity is with SCSI 1 & 2, that will be the basis of any of my thoughts here.