Q: Verify USB/UASP mode in Mac OS X
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)
Posted on May 3, 2014 12:30 PM
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
Posted on May 12, 2014 12:07 PM