I'm not sure if IOUSBAttachedSCSI loaded tells us anything... I just
checked with my MacBook Pro and before plugging in anything both it and
IOUSBMassStorageClass were not loaded.  Then I plugged in my Apricorn cable
with SSD attached and both these changed to say loaded=yes.

So how to I tell if the device is actually using the faster protocol I
wonder?  Google turns up...
https://discussions.apple.com/thread/6164330
and using the method described here I find that my Aprocorn cable does use
IOUSBAttachedSCSI which suggests that I would not get better performance
buying the startech one.

So I now turn to my iMac desktop into which I have a couple of external
drives connected, one for TimeMachine, the other as mass storage for my
music and video library (my iMac is 100% built in SSD for FCP X
performance, so I use external drives for the non performance-critical
storage).  Plug in my Apricorn and SSD and confirmed that it uses
IOUSBAttachedSCSI.   But now I discover that my WD My Passport 2TB external
drives are using IOUSBMassStorageClass.  I checked a seagate drive I use
for TimeMachine on my MacBook Pro and it also uses MassStorageClass.
Somehow I'm not excited about that.  Now I know to look for UASP support
next time I'm shopping for external drives.

David


On Wed, Oct 29, 2014 at 5:56 PM, Lonnie Abelbeck <[email protected]>
wrote:

> Hi David,
>
> I don't know...  What I can say the StarTech cable will erase a 32 GB
> SATA3 SSD in under 5 minutes and write the AstLinux image in a few seconds.
>
> I've never head of the UASP "USB Attached SCSI Protocol" before I saw this
> cable: http://en.wikipedia.org/wiki/USB_Attached_SCSI
>
> As per the wiki entry, on my OS X 10.9 system...
> --
> System Report... Software -> Extensions -> IOUSBAttachedSCSI -> Loaded: Yes
> --
> So it may be worth $15 to try with Amazon Prime:
> http://www.amazon.com/dp/B00HJZJI84/
>
> Lonnie
>
>
> On Oct 29, 2014, at 3:34 PM, David Kerr <[email protected]> wrote:
>
> > Lonnie,
> >   Thanks for the pointer to the USB-SATA cable.  Their website seems to
> claim that UASP support greatly improves performance over "standard"
> cables.  Have you compared this to other cables and have any experience?  I
> have a Apricorn cable I bought last year...
> > http://www.newegg.com/Product/Product.aspx?Item=N82E16812161005
> > and it seems to work pretty well (I use it with a Crucial CT256M4SSD2CCA
> SSD)  I'm just wondering if $15 will buy me extra performance (on a MacBook
> Pro).
> >
> > David
> >
> > On Wed, Oct 29, 2014 at 4:13 PM, Lonnie Abelbeck <
> [email protected]> wrote:
> > For those that use the Mac OS X "os-x-cf-write" script, an update can be
> found here:
> >
> > http://lonnie.abelbeck.com/astlinux/info/os-x-cf-write.php
> >
> > Changes include:
> >
> > 1) Use /dev/rdiskN instead of /dev/diskN - faster and works better with
> USB 3.0 connections.
> >
> > 2) add a bs=64k to dd - faster
> >
> > 3) continue to try a few eject's if the first fails
> >
> > 4) check if the script is run as 'sudo' at the beginning
> >
> >
> > FYI, Also I received a new gizmo, $15 USD on Amazon...
> >
> > USB 3.0 to 2.5” SATA III Hard Drive Adapter Cable w/ UASP – SATA to USB
> 3.0 Converter for SSD / HDD
> >
> http://www.startech.com/HDD/Adapters/USB-3-SATA-adapter-cable-with-UASP~USB3S2SAT3CB
> >
> > Much faster when I connect directly to my Mac with USB 3.0 .  It also
> works fine with USB 2.0 .
> >
> > Using this adapter a 32GB 2.5" SATA3 SSD can be erased and written in
> under 5 minutes when connected to USB 3.0. Recommended.
> >
> > Lonnie
> >
> >
> >
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> >
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> [email protected].
> >
> >
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> >
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>
>
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