So I decided to look into alternatives. For the SCSI bus I found an adapter (SCSI2SD) that connects to the internal standard 50pin SCSI port. It uses a micro SD card to simulate a hard disk.
Formatting the card as a drive was a bit tricky.
- You need floppy discs / CDs to boot from.
- After booting from floppy disc / CD you need to format the card as a hard disk.
- Apple's tool Apple HD SC Setup will only format Apple drives.
- You need a patched version (www.lowendmac.com) of this tool.
- Depending on the Mac you won't be able to use all the space on the card (2 GB is usable completely under System 7, 16GB shows only 2 GB),
- After partitioning you can install the OS from floppy disc / CD.
- It would be possible to install different OS versions on the same card. But I think selecting which OS to boot next can only be done from running an OS (not before booting like on newer Macs).
- Putting each OS on a separate card seems to be best.
Step by step with the LC 475:
- Create a system tools disc from System 7 and the patched formatting tool
- Boot the LC from this disk with the SCSI2SD adapter connected and the SD inserted
- Start the patched tool
- Initialize the SD card (SCSI device 0)
- Partition the SD card (Maximum Macintosh)
- You can now use this card to install an OS on it
- While installing there might be a warning "the driver on the hard disk could not be updated", just click "continue"