Dell Studio Slim has small tower/box form factor, but it still offers some space for adding a few extras.

For storage needs, it has space and power cable for one more internal 3.5” SATA hard drive. There’re two unused SATA ports (SATA 4/5).

I have chosen to add an external SATA port adapter on the rear panel and wired it to an external hard drive enclosure using a SATA cable. The enclosure contains two Western Digital 1TB Green hard drives configured in RAID 1.