sata-port-multiplier · shipping · also SATA PM, SATA PMP

SATA port multiplier

A SATA port multiplier connects several downstream SATA devices to one host SATA port.

Related Observatory article: SATA port multiplier on hesela.com

Device ports use addresses 0 through 14; address 15 is the control port, not a sixteenth disk. Cascaded multipliers are not supported. [1]

The devices share the upstream link. Adding drives expands attachment capacity, not the host port's bandwidth. Host support and the switching method matter when several drives are busy. [2]

A COMRESET issued to the host port resets every attached device. Separate downstream disks therefore do not imply independent reset scope. [3]

Relations

related
Serial ATA (SATA), AHCI, SATA Frame Information Structure, Command-based switching (SATA), FIS-based switching (SATA)

Citations

  1. SATA-IO Serial ATA Revision 3.5, sections 10.4-10.5 and 16.1-16.3: FIS and port multipliers (accessed 2026-10-19)
  2. Scott Knowlton, Synopsys: Understanding SATA FIS-Based Switching (2013), connectivity and shared bandwidth (accessed 2026-10-19)
  3. Intel AHCI 1.3.1, sections 9.3.6.1-9.3.6.2 and 9.3.8: device-specific recovery and host-port reset (accessed 2026-10-19)
Sources & caveats
  • SATA-IO sections were checked through indexed primary-specification text; direct PDF retrieval was unavailable. [1]

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Hesela team. SATA port multiplier. Hesela. 2026-11-12. https://hesela.dev/terms/sata-port-multiplier/