While you can’t get a copy of the original operating system developed by AT&T, you can get a taste of the UNIX operating system by installing a free UNIX-based operating system. One of the most popular, best-documented, and easiest to get started with is Free BSD. The software is available as a free download, and there’s an extensive handbook to help you get started. If you’re new to UNIX and Free BSD, take the time to review the free tutorial available from Free BSD before you do anything else.