+=============-========================-=============+ | Code | Description | Support | |-------------+------------------------+-------------| | 000b | Blocks | Mandatory | | 001b | Filemarks | Mandatory | | 010b | Sequential filemarks | Optional | | 011b | End-of-data | Optional | | 100b | Setmarks | Optional | | 101b | Sequential setmarks | Optional | | 110b - 111b | Reserved | | +====================================================+