I have several 'emergency' tools, focused on hard disk and system failures. All these, should be able to boot a mac, in case of a problem. Several bootable utilities, each one claiming it's own 'media' to boot a mac. The problem I face is that all new mac do not have dvd drives, and also I want to detach from them. So, what option do I have? Usb flash disks or similarly, several sd cards. Unfortunately, I cannot afford having a dozen of them. I cannot afford dedicate a separate usb flash disk for each one of these boot utilities. I would like to be able to use a flash disk in any way I want(daily tasks, transferring data etc), but in case of a mac problem, I want to be able to use it as a bootable device too. Is this possible? Can I do it and how? I tried copying a specific bootable dmg in a folder of the root of my flash disk, I even tried and copy-paste in other folder all the files(without the dmg image) of the image, but when I booted mac pressing 'alt' button, I could not see any option of alternative booting. So, how can I do it? I hope there is a solution, other from purchasing many usb sticks or reverting back to cheap dvd disks.