SCSI tape drives can be accessed like disk devices in Unix, so you should be able to use dd to make the tapes:
dd if=amix_tape_file of=/dev/st0 bs=512
No idea what corresponds to tape drive 0 in GNU/Linux, but it should work just fine there, too.
The original Amiga Unix installation tape contains a sequence of components, some of which are script files, some of which are compressed cpio archives. The components are separated by markers, which when read come out as EOFs.
Hence, in order to read the tape you need to use the non-rewinding variant of the tape device (I don't quite remember what its name was; it's been almost 20 years since I last installed Amiga Unix), or you'll only succeed at reading the first component over and over again
Likewise, writing the individual components to tape also requires that you use the non-rewinding device (if you want to install it from the original A3070 drive, or something that worked like it), or you'll only end up overwriting the first component with all subsequent components.
