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About UASP(USB attached SCSI protocol) ...

Posted: Wed Dec 26, 2012 5:41 am
by liaoo
Dear all,
I have 2 questions about UASP(USB attached SCSI Protocol) and maybe you can help me to clarify them. Thanks in advance...
  • 1. Though UASP is the specification in protocol layer,the hardware and firmware should be modified to co-work with driver. For example ASUS Z77 motherboard included Asmedia USB 3.0 controller chip which is UASP compatible, and ASUS also provided the UASP driver for their motherboard.

    My question will be: device(Ex. USB 3.0 Pen-drive or HDD) should also be modified to support UASP, right ? (That is, the device hardware and firmware should be modified, or UASP feature is not activated even with UASP driver and UASP-compatible controller chip)

    or we can use "existing USB 3.0 HDD or Pen-drive" and then UASP can be enabled with these 2(driver+controller) ?
  • 2. UASP is based on USB 3.0 Bulk Stream and built on top of it. We can imagine multiple streams with different Stream ID share the same pipe(communication pathway) and streams are transferred via host/device multiplexing...

    My question is:Assume there are 2 streams(ID = 1 and 2) then the processing sequence might be:

    case 1:
    - stream 1 is selected and then process stream 1 "until all data is processed"...
    - then stream 2 is selected and process stream 2 "until all data is processed"...

    case 2: stream 1/2 will be divided into multiple sub-streams and the processing sequence is
    - process part of stream 1
    - process part of stream 2
    - process part of stream 1
    - process part of stream 2
    - ...
which one is correct ?