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You can continue to find trusted guidance and support on the official Apple Support site.
We want to thank the community members who have contributed their time and expertise to help others with their Apple products.
Hi,
I would like to discern whether a connected USB hard-drive is using USB Attached SCSI transfer mode (UASP) or simply the old USB Mass Storage.
I have been googling and all I find is to check if IOUSBAttachedSCSI is enabled or IOUSBMassStorageClass... but both are at the same time.
Thanks in advance!
Víctor
MacBook Pro with Retina display, OS X Mavericks (10.9.2)
Hi,
In case anyone has the same question here is the best method I have found to check UASP mode. It involves executing ioreg command under terminal. The output of this command is massive so it is better if you redirect the output to a file and then open and inspect it separately:
ioreg > ~/Desktop/ioreg.txt
If you open the file, it is an ASCII build tree of devices. You need to inspect the file and search for IOUSBAttachedSCSI string. You may find a line like this:
| | | | +-o IOUSBAttachedSCSI <class IOUSBAttachedSCSI, id 0x100000d28, registered, matched, active, busy 0 (3800 ms), retain 9>
If you go a couple of lines above that line (within the same hierarchy) you should see what USB device this refers to... in my case:
| | | | +-o Neutrino U3+@15111000 <class IOUSBDevice, id 0x100000d22, registered, matched, active, busy 0 (3918 ms), retain 10>
The enclosure I wanted to test is in fact a Neutrino U3+ so now I know it is being driven via UAS Protocol.
In case the enclosure/drive does not support UASP you should see IOUSBMassStorageClass string.
| | | | +-o IOUSBMassStorageClass <class IOUSBMassStorageClass, id 0x1000006a9, registered, matched, active, busy 0 (3874 ms), retain 9>
Well, hope this clarifies the situation and you can unconditionally assess whether a USB drive is UASP ready or not.
Cheers,
Víctor
Hi,
Just tried to fin out if my external USB drives really use UASP on El Capitan.
Apparently on El Capitan the UASP driver has a new name "IOUSBMassStorageUASDriver" replacing the previous "IOUSBAttachedSCSI"
e.g.:
+-o IOUSBMassStorageUASDriver <class IOUSBMassStorageUASDriver, id 0x100000604, registered, matched, active, busy 0 (8345 ms), retain 9>
hope this is useful for someone
nm
Nice find. A quick way to get that info, without reading through so many lines is this:
$ ioreg |egrep 'IOUSBAttachedSCSI|IOUSBDevice|IOUSBMassStorageClass'
It will only list the lines related to those USB entries, in my case:
| | | +-o HP HD Webcam@1d170000 <class IOUSBDevice, id 0x10000026f, registered, matched, active, busy 0 (72 ms), retain 12>
| | | | +-o IOUSBDeviceUserClientV2 <class IOUSBDeviceUserClientV2, id 0x100000398, !registered, !matched, active, busy 0, retain 7>
| | | +-o BCM20702A0@1d132000 <class IOUSBDevice, id 0x100000273, registered, matched, active, busy 0 (746 ms), retain 14>
| | | +-o Apple Keyboard@1d134200 <class IOUSBDevice, id 0x100000509, registered, matched, active, busy 0 (352 ms), retain 12>
| | | +-o Firebird USB Flash Drive@1d140000 <class IOUSBDevice, id 0x100000631, registered, matched, active, busy 0 (463 ms), retain 9>
| | | +-o IOUSBMassStorageClass <class IOUSBMassStorageClass, id 0x100000637, registered, matched, active, busy 0 (240 ms), retain 9>
Verify USB/UASP mode in Mac OS X
