I’m wondering why this shows up as a single drive and not two drives. I wonder if it’s actually done sanely as a SATA bridge and two separate SATA devices, with a crazy Windows driver to make it into multiple partitions on a single logical device? Done right, this would be a great device for a Linux system. Done wrong, it would be a stupid device for any system. The mention of having to unlock the device with a special “USB key” makes me fear that it’s done wrong. Anyone know?

WD Black² Untitled Page


Eugene Crosser November 26, 2013 02:23

I don’t know anything more than is written on their FAQ page, yet it is written there that the “USB key” is only used to direct the user’s browser to the driver download page. And because it’s also written there that without the driver, the system will see the SSD part of the device, my educated guess is that they have separate SATA devices, either connected via SATA bridge, or with the interface switchable between the devices with the help of some proprietary magic. The latter option seems less likely.

Michael K Johnson November 26, 2013 05:41

The screenshots of windows partitioning showing a single device with two partitions is what makes me wonder…

Eugene Crosser November 26, 2013 08:35

Apparently, the correct name for SATA bridge is “Port multiplier” (http://en.wikipedia.org/wiki/Port_multiplier), and most likely it is not used in this device, because “Many common controllers do not support this feature”, and WD does not mention any possible hardware incompatibility. Which means less hope that it can be used with Linux.

Jes Sorensen November 26, 2013 09:21

I know there are solutions out there allowing the use of a separate SSD cache with a spindle, like Intel’s Smart Response stuff, which we don’t support under Linux besides treating them as two separate drives. I was told that there are drives which ‘do the right thing’ behind the scenes out in the wild, I think WD was mentioned, but I haven’t tested them.

Sounds like you need to do some testing and report back? ;)

Michael K Johnson November 26, 2013 09:24

Thanks, Eugene, I’ve known “port multiplier” in the past, just spaced on it last night…

I’ve been pondering getting a new laptop (my T60 is starting to show its age a bit) and swapping hard drives to switch OSes; occasionally Windows for using DxO Optics Pro and programming my GPS datacards, and Linux for everything else. That would give me an excuse to find out whether Linux can see the drive. But I’m still holding out on wider availability of Reasonable Resolution™ displays. At this point, why settle for less than 3200x1800? ☺ (Or maybe I just hate spending money?)

Jes Sorensen November 26, 2013 09:27

you have really good eyesight if you can spot the pixels on a 3200x1800 display on a laptop sized screen ;) I noticed the new Lenovo Yoga 2 Pro has that grade of resolution for a price that was not totally insane - went for the Yoga 13 instead though, as it’s for my personal laptop.

Michael K Johnson November 26, 2013 09:44

I don’t want to see the pixels! I’m spoiled by the resolution on my S4, I guess… I was looking at the Yoga 2, but I think it only takes the thinner hard drives, I’m not sure I want the folding-over feature, I might want larger than 13 inch screen, and so I haven’t even gotten as far as asking whether (for example) Linux supports the touch screen on it…

Jes Sorensen November 26, 2013 09:48

Will find out when I receive mine if the touch screen works - admittedly the touch screen wasn’t a deciding factor. Not really big on having big greasy fingerprints on my screen :) I liked the folding idea - good for movies on the plane without ending up with multiple laptop pieces when the guy in the seat in front leans back. 13” was a major plus too - laptops should be small, for the big screen they have the plug on the side which plugs into the desk monitor and keyboard :)

I can let you know on the touch screen once I receive it and try it out.

Eugene Crosser November 26, 2013 10:16

Yes, the lack of decent monitors is one of the reasons why I decided to replace the battery and stay with my old x200s for now, instead of buying a new laptop.

Aaron Ward November 26, 2013 14:27

The single-drive limitation is only present until “unlocked.”  Afterwards, it will show up as 2 drives, even when put in other systems (without needing to using the unlock software).

Michael K Johnson November 26, 2013 14:35

+Aaron Ward thanks! So is it a driver quirk on Windows that it shows up as two partitions on the same drive (according to the screen shots on the product page) instead of as two separate drives?

Jes Sorensen November 26, 2013 14:44

+Aaron Ward does this mean the drive does transparent caching until it is ‘unlocked’ or does this mean it doesn’t do any caching at all until unlocked and it requires special caching software under Windows to run in caching mode?

Aaron Ward November 26, 2013 15:03

My info was from pg. 3 of: http://www.pcper.com/reviews/Storage/Western-Digital-Black2-Dual-Drive-Full-Review-120GB-SSD-1TB-HDD-single-25-package

It specifically treats it as two separate devices under disk management, with no caching.  Specifically: “Now I know what you’re thinking. You’re probably wondering what happens if, say, your OS gets stuck in a blue screen loop, or gets infected with a virus. How can you access the 1TB of space without being able to boot the OS? The answer to that is simpler than you think. The software is not really a ‘driver’. Once it’s been installed and ‘unlocks’ the 1TB appended onto the SSD, it stays there. You could remove the Black2 from the installed system and connect it to a completely different system (via SATA, USB, whatever), and the full 1.1TB drive will appear, just as it did in the above pic. This applies even if the system you connected it to has never seen the Black2 driver software. Basically the unlock / driver install process is only there to ensure the HDD space is untouced during initial install and that the second HDD partition is placed correctly.”

Michael K Johnson November 26, 2013 15:15

Thanks for pointing to that! So from the OS perspective it is specifically a single device with carefully placed partitions. +Eugene Crosser’s point about poor port multiplier support makes that a defensible design choice, even though it makes me sad…

Jes Sorensen November 26, 2013 15:22

+Aaron Ward now I am getting really confused. Are you saying that when the drive is unlocked, it simply behaves as one large drive with the two concatenated together and the OS has to take care to place files to be ‘cached’ in a certain area of the combined drive? In other words, it means the user will see 1.1TB of storage, and the SSD is not used as a caching front-end to the rotating drive?

Aaron Ward November 26, 2013 15:39

I believe yes, it’s like one device with two partitions, but no, I don’t believe there is any caching.  It behaves like separate SSD and HDD, unlike other hybrid SSD+HDD devices where the SSD is very small and behaves like a cache.  See Disk 0 here: http://cdn.pcper.com/files/imagecache/article_max_width/review/2013-11-25/WD%20Dual-33.png

Jes Sorensen November 26, 2013 15:44

Thanks for the clarification - in the  image there, is that a physical cache drive with a special windows driver for it? Smart Response or Express Cache style? I am actually looking for drives where the SSD portion is made transparent by the drive firmware, but haven’t found any yet (only just started looking though).

Eugene Crosser November 26, 2013 16:04

If once “unlocked” with windows software, it becomes visible to the system as one SATA disk, without relying on a proprietary driver, it might be usable on Linux.


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