The HiMD Walkmen are SCSI disk drives. They only use the LUN zero.

These standard SCSI commands are used:
  * 00: [[http://en.wikipedia.org/wiki/SCSI_Test_Unit_Ready_Command|Test Unit Ready]]
  * 03: [[http://en.wikipedia.org/wiki/SCSI_Request_Sense_Command|Request Sense]]
  * 12: [[http://en.wikipedia.org/wiki/SCSI_Inquiry_Command|Inquiry]] (only page 0, standard inquiry) Vendor specific inquiry part: 36-43 = "UMD ID"; 44/45 = System Info; 46/47 = Command info [16 bit words little endian]
  * 15: [[http://en.wikipedia.org/wiki/SCSI_Mode_Select_Command|Mode Select (6)]] (see below for pages)
  * 1A: [[http://en.wikipedia.org/wiki/SCSI_Mode_Sense_Command|Mode Sense (6)]] (see below for pages)
  * 1B: [[http://en.wikipedia.org/wiki/SCSI_Start_Stop_Unit_Command|Start/Stop Unit]]
  * 1E: [[http://en.wikipedia.org/wiki/SCSI_Start_Stop_Unit_Command|Allow/Prevent medium removal]]; "Start motor" not suppoted
  * 23: Read format capacities (see SFF-8070i, link below)
  * 35: Synchronize Cache, "Immed" bit at Byte 1, Bit value 0x02
  * 55: [[http://en.wikipedia.org/wiki/SCSI_Mode_Select_Command|Mode Select (10)]] (see below for pages)
  * 5A: [[http://en.wikipedia.org/wiki/SCSI_Mode_Sense_Command|Mode Sense (10)]] (see below for pages)
  * A3: Send Key - [[SCSIDRMInfo]]
  * A4: Report Key

They support the following extensions to standard SCSI disk drive support:
  * C0: Read HiMD
  * C1: Write HiMD
  * C2: [[HiMD device control|SCSIHiMDControl]]
    * C2/00: Erase HiMD
    * C2/01: Format HiMD
    * C2/0E: Begin ICV Transaction
    * C2/0F: Recommend Synchronize Cache
    * C2/10: Switch Interface
    * C2/11: Get Leaf ID
    * C2/20: Load Audio TOC
    * C2/21: Pause Audio
    * C2/22: Play Audio
    * C2/23: Scan Audio
    * C2/24: Search Audio
    * C2/25: Seek Audio
    * C2/26: Stop Audio
    * C2/40: Read Defect List
    * C2/41: Read Zone List
    * C2/50: Get Time
    * C2/60: Read Audio Status
    * C2/90: Set Time
    * C2/A0: Extended Play Audio

The following mode pages are supported
  * 01: Read/Write Error recovery parameters
  * 08: Caching
  * 1B: Removable Block Access
  * 1C: Timer and Protect
  * 21: HiMD Playing
See [[ftp://ftp.seagate.com/sff/INF-8070.PDF|SFF-8070i]] for more information about all mode pages except for the HiMD playing page.

See [[HiMDDownload]] for a trace of downloading a short LPCM track to an HiMD device using Sonic Stage