ExtenDOS 4 provides support for industry-standard CD-ROM formats, including:
 | High Sierra |
| basic ISO9660 |
| ISO9660 interchange level 2 (long filenames) |
| major ISO9660 extensions, including mixed-case filenames, the Joliet filesystem, and the Rock Ridge Interchange Protocol |
| the "CD Extra" format for audio CDs |
| single session & multisession CDs (requires compliant drive) |
You can switch between supported disk formats without a reboot. ExtenDOS 4 even provides a built-in configurable cache facility to speed up data access.