Well... AS/400 scsi drives are recognized by the string IBM AS/400, during the inquiry
phase.
They can be used in a standard PC, if reformatted at 512 bytes/sector, since OS/400 use
520 bytes/sector.
If they come unformatted or degaussed, you can reformat it at 520 under a *nix system with
sg_utils (e.g. Linux) and used (I tried it successfully on different AS/400 systems).