How do i make my hard drives work as One?

Sorry if this slightly off topic but its better than starting a thread for it so..
If I want 4 HDD's and i have all the current connections occupied, how is it possible to do it ? Would RAID PCI Controller's be the answer ? And yes I do intend to keep my OS on Primary.

 

Thanks, power connectors isn't an issue for me. I have a few multipliers and a few un-connected.
edit=
If i go for the standard ide controller would all the drives on it still be recognized as the smallest hdd's size ?

 

WOW that's a relief thanks for the tip

 

Howzit goin' guys?
If running WinXP or Win2K, b0nkers needs to simply go into Computer Management > Disk Management, then convert his basic harddisks to Dynamic Disk(s).
He can then extend his volume(s) to span multiple HDs :^)
But remember: no going back! It's a one-way trip (kinda like an NTFS conversion).
A typical new mobo will support 2 ATA plus 4 SATA, with RAID available for SATA if desired.
Striping without parity (RAID 0) is for speed gains, but dangerous.
Mirroring (RAID 1) is for redundancy = data safety.
Striping with parity (RAID 5) is a good plan, and supported by Windows in software, on Dynamic Disks.
Hardware support with new SATA mobo's is preferable though, but not really useful to most folks... (HDs not usually system bottleneck.)
If wanting to add more HDs to a PC, you could look at a PCI SATA controller like this:
http://www.promise.com/product/product_detail_eng.asp?segment=Non-RAID HBAs&product_id=139
Or else spend the big $$$ (WTF:^) and invest in this:
http://www.promise.com/product/product_detail_eng.asp?segment=RAID HBAs&product_id=124
Promise IDE controllers have been around long time for older ATA style HDs though - and they cost less too (both controller and HDs).
L8R