Nick Kennedy's SIO ATR file format with a 16 byte header.
File contains only the raw disk sectors.
Has a 16 byte Macintosh header. In MyDOS format, you can create virtual disks from 720 to 65535 sectors of 128 or 256 bytes. Arrow keys now scroll and wrap file directory selections correctly. Other minor internal tweaks and interface bug fixes. Virtual disks with imported Atari DOS or MyDOS DOS files are now bootable.