Boot iMac from an OS X Live DVD or USB thumb drive?

[GameGuru38]

With Linux I love that I can boot from disc or USB so I can do some tests on the internal HDD and wondering if there is a way to do this with OS X so I can run a diagnostic on the HDD before attempting to install to it?

 

[redheeler]

You can create a bootable USB installer and run Disk Utility from there.

Edit: Missed that you're running Lion. Instructions for Lion are here: http://www.macworld.com/article/1161069/software-system/make-a-bootable-lion-installer.html Sorry, misread the title.

 

[Weaselboy]

With Linux I love that I can boot from disc or USB so I can do some tests on the internal HDD and wondering if there is a way to do this with OS X so I can run a diagnostic on the HDD before attempting to install to it?

https://support.apple.com/kb/DL1433

You can use the Apple tool at this link to make a recovery USB key. This is not a full OS installer, but just a small recovery utility that you can use to access things like Disk Utility and Terminal for troubleshooting.

 

[abhibeckert]

USB drives are damaged whenever you write to them, so it's not recommended to run a full OS X install on one.

It will work, but only for a while then you'll have to buy a new thumb drive. According to Wikipedia, how long it will last varies from "a few days" to "several hundred years" depending on your usage pattern.

Booting a normal OS X is probably closer to "a few days", which is why you should only really use the recovery feature - that is designed for thumb drives and won't wear it out too badly.

If you're frequently doing diagnostics/etc you should use a proper HDD or SSD in a USB enclosure. Or even better, thunderbolt.