Ok, Ill have a crack at this, There are 3 different types of SCSI, scsi, scsi 2, and ultra wide scsi, the actual ultra wide scsi cable is narrower than the scsi 2 cable because its sorta woven, its actually very nice to look at, scsi cables have either 50 or 64 pins, they used to be all the rage but will probably be superseded within a couple of years.
There are 5 different levels of RAID, dont ask me what they all are because it would take all week to detail them, ide is actually the term used to describe the type of hdd, eg scsi or IDE, and I believe you can have a ide raid array.
Hope this helps