These are floppy disk and CD-ROM images containing MikeOS and accompanying programs. mikeos.flp and mikeos.dmg are identical -- the latter can be used on Mac OS X without having to change the extension. You can use 'dd' on Linux or RAWRITE on Windows to write the floppy disk image to a real floppy. Alternatively, you can burn the .iso to a CD-R and boot from it in your CD burning utility. Note that the CD image is generated automatically from the build scripts, and uses the floppy image as a boot block (a virtual floppy disk). In Linux/Unix, you can create a new floppy image with this command: mkdosfs -C mikeos.flp 1440 The build-linux.sh script does this if it doesn't find mikeos.flp.