Setting Up RAID-5 Array

You should not need all drive bays full.  That would shoot expansion out the window.
I believe this would happen to be in the drive ID of that first drive.  Are you sure it is unique?

When you say it doesn't get recognized, do you mean by the os?

Also, you sure its set to raid 5? Raid 3 is the same except 1 drive is used for parity so this could cause it to dissappear.

Double-check your jumper settings on the drives.  I know I've made that mistake, where I've set the drive jumpers wrong so there was a conflict.

Just a thought.

--Greg

If you swap that drive into another slot does it work?  And does another drive in that slot work?  I agree with the previous comments that an ID problem is likely, but it's a quick check to make sure it's not the slot.

Carefully compare the jumpers on the non-working drive versus a working drive.  All the jumpers: don't neglect parity, termination, and so on.  Jumpers may be in more than one location. Check 'em all.  The ONLY difference should be SCSI ID ( assuming you're using an external terminator ).
Pay attention to the termination: one at the controller, the other at the end of the line - and that's it.  SCSI is picky, picky, picky about details.  Look for a bent pin in the cable header on the drive.
Boot into your controller's firmware ( not familiar with Adaptec, but it's CTRL-M or CTRL-A or some such ), right away the controller will tell you what drives it sees.  You may need a Lo-Level format.

Ok. Thanks for the posts over the weekend. Let me try to provide answers all in one shot ... yes there is termination on both ends, the cable is terminated just past the controller and the drive module is terminated on its final connector. Sometimes the controller will say it sees multiple SCSI ID's (usually omitting the actual ID's I've set for the drives). I know all of the drives are functional, I've trying swapping their positions, etc. When I say it's not recognized, I mean the drive is not recognized by the Adaptec SCSI controller. I haven't even reached installing the OS yet. The SCSI adapter is ID 7 by default. The drive module can be set to either SCSI ID's 1-5 or 9-13. I've tried both settings (adjusting the ID settings on the drives as necessary), this doesn't seem to help.

I guess I have another question. Can the ID of the first drive be set out of sequence in comparison to the other drives? For example, can I set the ID of the first drive to 5, then 2,3,4 for the following drives? Thanks for your help.

Drives are numbered sequentially only by convention.  You can make any drive any ID as long as it's unique.  That your controller is ID 7 is of concern, I'd rather see it be 15 to be sure that the controller is using the full 4 bits available.
Yours is classic SCSI trouble.  You WILL find something wrong.  Now it's time for another set of cables and terminators; if you are absolutely, positively sure all jumpers and firmware setup is in agreement vis-a-vis parity, termination, width, etc.  You might try throttling the Adaptec controller back to the lowest SCSI buss speed - your drives should follow suit.  Welcome to the wonderful world of SCSI at its best!