Many a times I had downloaded an ISO image and burned CDs out of it. I never thought what is the disk image format and how they were created. I am thinking of these questions only when a need arise. A blog post from a Indian regional language(Tamil) blog pointed me to a right source to create the ISO image file.
An ISO image file is an image of a CD-ROM disk saved in ISO 9660 format. ISO image files are widely used to store CD content and transfer it through the Internet. ISO is a common CD image format for DOS, Windows (Joliet ISO extension), Linux (RockRidge ISO extension) and other operating systems.
Most popular CD recording programs can burn ISO images onto recordable CDs. Some of these programs even use ISO as their native disk image format.
Undisker can create ISO images of CDs. Follow these instructions to create an ISO image of a CD:
1. Run Undisker. This tool can be downloaded from here
2. Insert the source CD into the CDROM drive
2. Select Capture CDROM from the Image menu
3. Type a filename for the image file
4. Choose ISO as the file format
5. Press the Save button
After you press Save, the capturing process starts. When the process is complete, Undisker automatically opens the newly created disk image.