CompuServe Thread

Rick, Some SCSI devices (like my CD-ROM) have a DIP switch to determine whether they will work with the SCSI or SCSI-2 command set. I've never tried using a SCSI-2 device on a SCSI controller. > What is the difference in size between a half height and full height > SCSI device? About half. <g>. Actually, this half height, third height nonsense comes from the disk drives on older (i.e. Apple II and IBM PC and older) machines where the drive fit into a bay on the computer that was about 3 inches high. Newer drives took up only half this space and were referred to as 'half height' drives. The difference to you is the size of the bays in your computer where the disk will go. If you have a full height disk you will need a full height bay for the disk to go in. In addition, there are 5 1/4 inch and 3 1/2 inch disks and bays. Rick – On Autopilot from Vancouver

Richard, I have a full-height 5.25 inch hard drive in an external case. Its huge compared to any of the half-height drives. It is so big that it and its power supply occupy a case that could house two SyQuest 5.25" drives or a couple of 3.5" devices with lots of space on the sides. It is also one very heavy device. Not easily mounted in your regular computer boxes, this would need a tower case for internal use. Christopher

Hi A 5.25" half height Bay is what you got on a Amiga 2000….. Amiga 3.5" Floppy are half height too… :=) Full height's twice as high… Axel from Hamburg Germany

I read the replies, but I think this may be clearer for you, Richard: In my experience SCSI 2 devices WILL work on regular SCSI board – it just won't achieve its maximum performance unless it has a real SCSI 2 interface board and appropriate driver software. Full height is 3.2 inches high (almost always a 5.25 inch width) Half height is 1.6 inches (typical 3.5 inch hard drive) Third height is 1 inch (newer 3.5 inch hard drives, also known as 'slim') Quarter height is the height of the 2.5 inch wide hard drives. Typically older hard drives (and some newer huge capacity ones) are 5.25 inch width, 'full height'. Technology advanced and drive makers squeezed capacity into 5.25 width, 1.6 inch height and 'half' height drives were born. Then the 3.5 inch width drives came out, all in 1.6 inch height. More recently the 'slim' 3.5 inch drives arrived and most recently the 2.5 inch babies you put in the Amiga 600 or 1200 and they are known as 'quarter' height. Amazing now that you can get 1Gig in a 'slim' 3.5 inch wide drive! Hope that helps.