Booting from TOS/Windows compatible drives

[uweseimet]

HDDRIVER can be booted from TOS/Windows compatible drives, as long as they have *not* been partitioned with byte-swapping enabled. This means that you can boot from TOS/Windows compatible drives/memory cards if they are connected to the Atari's ACSI or SCSI bus. It does not matter how these drives are accessed on the PC or Mac, e.g. SCSI, IDE, SATA, USB. On other platforms the byte order is always the same, regardless of the bus. Only with the Atari the IDE byte order is unfortunately incompatible with any other platform.
TOS cannot boot from TOS/Windows compatible media connected to the Atari's IDE port, because in order to be PC compatible the data have to be stored in PC byte order. The byte order is a property of the drive/memory card, not just of a single partition. In order to boot from a byte-swapped drive, hardware modifications or a modified TOS are required.

It is recommended not to use the boot drive for exchanging data with other platforms, i.e. not to partition the boot drive TOS/Windows compatible. Windows and macOS (but not Linux) tend to write (potentially hidden) files to a drive, which may cause issues like files with strange names, which cannot be deleted by the desktop. Use TOS compatible media for your daily work with TOS, and only use TOS/Windows compatible media for exchanging data with other platforms.

[uweseimet]

Note that everything said before also applies to media partitioned with a platform-independent GPT (GUID Partition Table) scheme instead of a legacy MBR scheme. HDDRUTIL supports partitioning with a GPT scheme since HDDRIVER 12.50.