Solid state devices have a lifespan: each bit can only be rewritten so many times before it just stops working. A write buffer lets the OS minimize this.
The ‘safely eject’ button is really just telling the OS that you’re not going to be dicking around with the files anymore, and it’s OK to finalize the write buffer.
I’m glad of the feature. I have applications that I run off the thumb drive regularly (it lets me mess around with them at work without installing onto the work computer.) The applications are constantly writing and deleting temp files and log files. If I don’t make sure to safely eject, I will corrupt the drive and need to format it. After two formats, I got the habit.
On Windows, if a storage device is listed as “removable” then Windows will not enable write caching for that device. Meaning, when you copy or save a file to that device, Windows will write the entire file right then and there. So in general, it’s safe to unplug the drive as long as its not being actively written to.
OS X and Linux, on the other hand, always want you to unmount the device first before unplugging it.
Sometimes when I’m feeling rebellious, I’ll just yank my iPod off after the one song that I’ve bought and need to download has finished its transfer. My computer can’t tell ME what to do!
Using a SD card or Memory Stick in a USB reader, I occasionally would forget the “properly eject blah blah” step, though it was long enough after I’d done any writing that the data would be perfectly fine and work without issue in the device the card was intended for.
However, what wasn’t okay is that thereafter, every time I connected the card and reader back up to the PC, Windows would bitch at me about how I’d previously removed the card improperly. The only way to get it to stop would be to run some fix (not the one the pop up bitchfest suggested either, I think I had to run something from a command prompt to get it to actually stop).
So now I always remove the device properly so I don’t have to deal with that again.
Not even Windows disables all write cashing to removable drives, it’s just extremely short. But, anyways, that’s why nearly all thumbdrives have that light to tell you when they are done. There is no reason for Windows to freak out if you remove it then. And as of Windows XP, they had stopped doing that, except in the rare cases where you did pull it out unfairly.
The exception appears to be with Blackberry phones, of all things. In Windows 7 at least, the driver doens’t work right if you remove things without ejecting both disk drives. But surely that’s another one of RIM’s horrible design flaws, like their app store that logs you out every time you download an app, and won’t let you save your username/password at all.
