[Discuss] External USB bridge to SSD

Dale R. Worley worley at alum.mit.edu
Sun Dec 11 15:15:57 EST 2022


> From: Rich Pieri <richard.pieri at gmail.com>
> Subject: Re: [Discuss] External USB bridge to SSD

> USB Mass Storage does not provide for TRIM/UNMAP. You need a USB
> adapter that specifically implements USB Attached SCSI Protocol (UASP)
> *and* the host needs to recognize the device as a UASP device.
> [various useful advice snipped; see the previous message]

At some point I thought I'd heard that the various various newer device
attachments used the SCSI command protocol.  Which certainly would be a
good design, since you wouldn't have to redesign all that stuff, and
just piggy-back on SCSI, letting them update the protocol.  If that was
true, a USB bridge would just pass through e.g. trim.  But I'm wrong,
and every piece of adapter has to be checked individually for whatever
features I want to use.

Dale


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