Template
Specify the type of backup medium. Templates are defined in <CONFIG_DIR>/<config>/template.d/tapetypes, except for HARDDISK, which is customarily defined in amanda.conf(5). You can add your own (if you do, please share it). Then use a specific template to define your tapetype for each configuration in amanda.conf(5).
For example:
tapetype HARDDISK # what kind of tape it is ... define tapetype HARDDISK { comment "Virtual Tapes" length 5000 mbytes }