SAS Cabling Roadmaps

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Serial Attached SCSI (SAS) burst upon the storage scene in 2004 as a serial replacement for the once ubiquitous parallel SCSI interconnect. While much attention is often given to the capabilities of the protocol and to the silicon and software required to implement these systems, it is often the physical interconnections that influence the adoption of I/O in a variety of market segments. Parallel SCSI, for example, supported everything necessary for clustered server deployments; however, the large unwieldy nature of the parallel cables and the restricted cabling distances greatly limited SCSI’s applicability in these markets.

SAS removed many of these restrictions by opening up the bandwidth, improving cabling distances, and providing a compact connection scheme suitable for today’s shrinking data center. While first generation solutions made tremendous strides forward, the connection schemes have continued to improve, opening up new markets for SAS in the process.

External Cabling Solutions

Notes:

  • This roadmap shows the external cable connectors for each generation of SAS, grouped by max cable length & type
  • “Active” copper cables contain circuitry that enhances signal quality, thus extending the length at which the cable will reliably operate
    • Cables not containing such circuitry are “passive”
  • SAS Connectivity Management refers to cables that support the Cable Management Interface (CMI)
  • CMI enables a host to determine the type and characteristics of an attached cable by communicating with logic within the cable assembly
    • Cables supporting CMI are “managed”
    • Cables not supporting CMI are “unmanaged”
  • Refer to latest SAS-4 specification for mechanical form-factor and electrical requirements

Internal Cabling Solutions

Notes:

  • This roadmap shows the connectors for inside-the-box cabled connections
  • Refer to latest SAS-4 specification for mechanical form-factor and electrical requirements

View / download the PDF version of these roadmaps (PDF 1.3MB)

SAS Device to Mid-Plane Interconnects Roadmap

Notes:

  • This roadmap shows connectors that enable SAS devices to plug directly into mid-plane connectors (no cable)
  • The connectors are grouped by standard dual-port SAS, MultiLink SASTM (two dual ports or one 4-port I/O), and Multi-Function (i.e, support for multiple interfaces; two dual ports or one 4-port I/O)
  • Refer to latest SAS-4 specification for mechanical form-factor and electrical requirements

View / download the PDF version of this roadmap (PDF 1.3MB)