It’s all about metadata
There are three basic NAS type devices out there:
* HP Media Server and clones: HP promoted their Media Server at Macworld as a “home file server.” This somewhat surprised me, given that it is running Windows XP Media Edition or whatever the Vista equivalent might be;
* The generic NAS stuff, produced by Iomega, Buffalo, etc. Every single one of these I’ve ever seen uses a cut-down version of Linux;
* Apple Time Capsule.
Let’s address the first two types as a lump. Windows and the Linux-based stuff share things that a Mac can read as SMB (Server Message Block) volumes. The Linux-based NAS units use open-source Samba (a pun on SMB) services, while HP Media Server uses Windows or Vista SMB services. The operating system part isn’t as important as the file system.
Now, what can you save in Windows? You can save a file, you can save the file’s “last saved” date, you can save its size. You _cannot_ save the icon directly; this is actually an abstraction through the registry. You _cannot_ save the icon color; Windows simply has never heard of this. If you want to change the icon, for example, you need to use a registry editor.
Cosmetics aside, you also don’t get much metadata.
What does a Mac save? It saves:
- Icon. Either an application-specific icon or, if you feel like it, any old icon you want to paste over the default. No limits;
- Icon color. Apple calls these “labels,” but whatever you call it, being able to color icons is quite useful;
- Size. You get a rounded-up size (10.2 megabytes) and an exact size (10,701,354 bytes);
- You get a created date;
- You get a modified date;
- You can tell if the file is stationary for something else;
- You can tell if it is locked;
- If it is a PDF, you can tell how many pages it is, the dimensions of the page, what software created it, and what version of the PDF specification was used;
- If it is a sound file, you get the duration in hours, minutes and seconds, the number of channels, and the bit rate, and you an even play it;
- If it is an image, you get what kind of image, dimensions of the image, device used to create the image (usually a camera), device model, color space, color profile, focal length, alpha channel, red eye, f-stop, shutter speed, and a preview of the image;
- If it is a video file, you get the kind, dimensions, codec, duration, channels, bit rate, and a preview;
- If any of these items happened to be saved from Apple Mail, you also get the sender name, address, subject matter, and date of the E-mail.
If you save a Mac file with all this nice, rich metadata on a NAS or Windows-based file share, most of the metadata is lost. Sometimes the file itself is lost, if the file share just doesn’t understand what the heck it is supposed to be, or if the file itself is complex (Pages pages are not pages but an entire directory bundled together, as are Keynote presentations).
A Mac OS X-based drive, or a Time Capsule, stores a staggering amount of information that simply doesn’t have an equivalent in the Windows or Linux-based NAS worlds.
What does this have to do with a Drobo? A Drobo can be formatted with a Mac OS X Extended (Journaled) volume. In other words, all this pretty metadata is preserved. Automatically.
Cool. You can even use it as a Time Machine store, if you wish.