Bootable CDs are discs that automatically load or perform a particular function if they are in your computer's CD drive as the hard drive starts up. For storage and transfer purposes, you may wish to copy a bootable CD onto a USB flash disk. Doing so entails the use of a disk imaging utility. Disk images are exact copies of a drive or disk's contents combined into a single file that you may readily transfer or use if necessary. On Windows-based computers these images are known as ISO files. They are DMG files on Mac-based computers.
Purchase and install a disk imaging utility, such as Nero Burning ROM, MagicISO or Acronis True Image (see Resources), if you do not already have a program of this nature.
Insert the bootable CD into your computer's CD drive.
Launch your disk imaging utility if you have not already done so. Select "Disk Image" or "Bootable CD/DVD Image" from the "File" menu's "New" tab.
Select your bootable CD's drive icon from the ensuing file browser or from the utility's browser pane. Drag and drop the drive icon to the utility's ISO panel if it has not automatically loaded there upon selection.
Click the "Save" button or select "Save" from the "File" menu. Name the file and select a save destination on your computer if you wish this to differ from the default location.
Insert the USB flash disk into an available USB port on your computer. Wait for your computer to recognise the USB flash disk as a connected device. Open the flash disk's file folder from Windows Explorer.
Click "Start" and open the file folder containing the newly created ISO file in a separate Windows Explorer window. Ignore this step if you saved the file onto your computer's desktop.
Drag the ISO file from its window into that of the USB flash disk and drop it on the USB flash disk icon. Doing so creates a copy of the bootable CD's disk image file on your USB flash disk.
Insert your bootable CD into the computer's CD drive.
Launch Disk Utility from the "Applications" folder.
Select the bootable CD from the list of drives and volumes in the left pane.
Select "New" from the "File" menu. Select "Disk image from disk name."
Name the disk image and select its save destination from the ensuing dialogue.
Choose "DVD/CD master" from the list of available disk image formats.
Click "Save" to create the disk image.
Insert the USB flash disk into an available USB port on your computer.
Double-click the USB flash drive's device icon from your computer's desktop. Doing so opens its file folder in Finder.
Open the file folder containing the newly created disk image in a separate Finder window. Ignore this step if you saved the disk image to your desktop.
Drag and drop the disk image file into the USB flash disk's file folder. Doing do creates a copy of the bootable CD's disk image on your USB flash disk.