HDDRIVER and its tools work well with various Atari emulators (except for Steem.SSE). There are special features for Hatari, ARAnyM, MagicMac and MagicPC. The HDDRIVER forum has a separate area on emulators.
On a real drive or a drive image HDDRIVER is installed with HDDRUTIL, so that TOS automatically launches HDDRIVER when booting. There are only two scenarios where it can make sense to place HDDRIVER in the AUTO folder: When booting from floppy disk and when booting from an emulator's GEMDOS drive. When using MagicMac or MagicPC the AUTO folder is the only option.
With Linux this SCSI Driver provides direct access to storage devices. Such a feature you might know from VirtualBox or VMWare. Supported interfaces are SCSI, IDE/SATA and USB. NVMe SSDs require an NVMe-to-USB adapter.
The SCSI Driver creates two buses 30 and 31, which support 8 native devices each. The driver can be launched as a regular program or as an HDDRIVER module. It is important to launch it before HDDRIVER, so that HDDRIVER has access to the mass storage devices managed by Linux. If you just want to use HDDRUTIL it is sufficient to launch the SCSI Driver before HDDRUTIL.
With Hatari the NatFeats support has to be explicitly enabled in the Hatari configuration file or on the command line. The devices are detected automatically without any further settings in Hatari or ARAnyM.
Under MagicMac and MagicPC HDDRIVER has direct access to SCSI devices if the native SCSI Driver by Steffen Engel for the respective platform and SCSIDRV.PRG (from the CBHD distribution) are installed. In this case the SCSI bus of the Mac or PC is visible within the emulator. In this special setup HDDRIVER.PRG has to be launched after SCSIDRV.PRG, e.g. from the AUTO folder.