The PiSCSI project (formerly RaSCSI) provides open hardware and software for the Raspberry Pi (except for the Pi 5), in order to emulate SCSI devices. PiSCSI can either be operated as SCSI Target or as SCSI Initiator. This means it can act as a peripheral as well as a computer.
In order to improve the stability and the compatiblity with numerous client platforms and to support more SCSI device types I have re-implemented large parts of the PiSCSI software in modern C++. Atari computers are explicitly supported, e.g. by ICD compatibility.

Raspberry PI Zero WH with PiSCSI board connected to a TT

PiSCSI emulates several devices at the same time, like hard disks, CD-ROM drives, printers, a DaynaPort network adapter or a realtime clock. This way you can easily add SCSI devices or a memory card reader to your Atari. All emulated devices are ICD compatible, which is important for the MegaSTE or STs/STEs without an ICD compatible host adapter. This way all SCSI commands can be used and up to 8 emulated devices can be connected to the MegaSTE's internal host adapter at the same time.

More on PiSCSI and Atari Computers with TOS
More on PiSCSI and Atari Computers with MagiCMac

PiSCSI also works with Linux-68k and Atari's System V Release 4 (ASV).

With the PiSCSI client tools the Atari can exploit the full PiSCSI functionality. Files can be printed via PiSCSI, the Pi or PiSCSI can be shut down, and a realtime clock with automatic daylight saving time adjustment is available.

With the PiSCSI Control app multiple RaSCSI/PiSCSI boards, the emulated devices, the image files and much more can be managed. The app can also shut down PiSCSI and the Pi.

In the HDDRIVER forum there is a special area on HDDRIVER, the PiSCSI Control app and the PiSCSI client tools.