Boot Menu List

I am a technician, and I have never tested this. What I am trying to do is purchase a large Hard Drive or 2 and use them for setting up and configuring macs, as well as to troubleshoot. I would like to purchase something very large and put as many images on it as I can.

The Question I have is what is the limit on number of boot volumes in the Boot Menu when you hold alt/option during startup. if there is no know limit, would at least 20 be possible?

I don't know what the limit is, but it might be better to use a free boot manager program instead. Take a look at rEFIt, it's open source. It's somewhat difficult to get working right but once it's setup it's much easier than using option to choose which OS to boot from.