There are a couple alternatives, though, and they're both fairly easy. Technically, you can still use Disk Utility to make a bootable USB drive, but the process is more complicated than it's worth. Unfortunately, that Disk Utility method does not work for the newest Mac OS X 10.9 (Mavericks) that was released as a free download on Tuesday. So, if you wanted a backup install disc in case something went wrong, or in case you wanted to install Mac OS X on your computer without signing into the Mac App Store, you'd have to create a bootable DVD or USB drive yourself using the InstallESD.dmg, which was an easy process using Disk Utility. There hasn't been any physical installation DVDs available for Mac operating systems since Snow Leopard (10.6), with Lion (10.7) and Mountain Lion (10.8) both available via the Mac App Store as downloads only.
