The RaSCSI board is now available for old Macs. You could potentially emulate HD’s and CDROM’s with it.RaSCSI is a virtual SCSI device emulator that runs on a Raspberry Pi. It can emulate multiple SCSI devices concurrently, provides a control interface to attach / detach drives, as well as insert and eject removable media. Simply launch the software, connect the RaSCSI interface board to your Mac and the devices will be recognized as physical SCSI devices!
Currently it is unknown whether it will work with the Apple IIgs but the challenge has been put to the people via posting on Facebook ; “Anyone want to see if they can get it to work with their Apple IIgs w/SCSI card?”
You can purchase the RaSCSI from the following page: