Hi,
It's 'SCSI' not 'scuzzy', and 'disk'(or 'disc' for the round flat ones) not 'disck'
You can't just plug it straight in.
For the A500 you will need a HDD unit plugged into the side that has a SCSI port on the outside.
On the A600 your best bet is to use a PCMCIA based SCSI controller.