Preserving GEMDOS drives

[uweseimet]

When running HDDRIVER inside an Atari emulation like Hatari in a mixed setup with GEMDOS drives and drive images, it is often useful to not touch the GEMDOS drives created by Hatari and to place the drives created for partitions on the drive images after them. Without configuring HDDRIVER accordingly, hard drive partitions will replace GEMDOS drives like this:

This is most likely not what you want, because you cannot access the GEMDOS drives C: and D: anymore. With the "Preserve existing drive IDs" setting you can prevent this. When assigning drive IDs to partitions, HDDRIVER will skip any already existing ID and the first drive IDs assigned by HDDRIVER will follow right after the GEMDOS drives:

This approach only works when HDDRIVER:PRG is started from a GEMDOS drive, usually from the AUTO folder of GEMDOS drive C:. When HDDRIVER.SYS is booted from a drive image, Hatari has not yet created its GEMDOS drives, and therefore HDDRIVER cannot preserve them.
Note that placing HDDRIVER.PRG in the AUTO folder only makes sense when the AUTO folder is on a GEMDOS drive, or when booting from a floppy disk. In any other case install HDDRIVER with HDDRUTIL as HDDRIVER.SYS on your boot drive.

If you do not want the drive IDs created by HDDRIVER to start with the first unused ID but with a different ID, you can explicitly assign the first ID of a drive with "Devices and Partitions". See the HDDRIVER manual for details.