#YOEO – You Only Eject Once

You’re in a hurry to copy some files, you quickly and clumsily plug your external storage device into the nearest device with an available USB port, copy whatever you need, then having completed the task at hand, yank out the device and then go about your life.

Unfortunately, you could have possibly just committed the biggest mistake you could ever make. You think I’m bluffing? Well think again!

Disk have feelings, too

With the exception of flash drives, most storage devices contain a literal hard disk drive complete with spinning platters and reading head – much like the hard drives you find in most desktop PCs. Indeed the only difference between these drives is the physical dimension. A regular desktop drive is 3.5-inch whereas an external hard drive usually has a 2.5-inch drive.

An external hard drive with its case removed, courtesy of wiseGEEK.

Thankfully, we don’t have to worry that much about the myth about hard drive heads losing power and causing damage to the platters – modern drives usually have enough capacitance built into the drive to “park” the heads in the event of power loss. The possibility of damage is very, very low. More troublesome is write caching.

By default, Windows and Mac operating systems utilize a protocol called “write caching” wherein the OS does not write the files to your storage device immediately, but rather waits for multiple files or requests to be fulfilled in order to save resources and boost performance. So when you hit that eject button, it basically tells the OS to flush or empty the cache, clean up and make sure the drive can be safely unplugged.

When you don’t hit the eject button, there’s a chance that the file you’re working on still hasn’t actually been written to the drive. By pulling out your drive, you simply lose that data. End of story. In fact, the only consumer OS where you can get away with it is Windows XP, which has write caching turned off by default.

Then there’s the buffer. Each and every disk contains a microcontroller embedded within its circuitry that is used to signal the main computer that a disk write is complete just after receiving the write data but before the data is actually written to the platter. This is called a “Buffer” and is given the sole purpose of being an early warning signal to allow the computer to continue working even though the data has not actually been written yet – after all, you CPU has better things to do than hang around waiting for a mechanical drive to write a file.

Basically, your computer may show that the files are copied, but your disk is still working. Even though the files may have been copied and the dialog box has vanished, the drive may still be accessing the disk buffer/cache. It can even happen if a window is open.

Needless to say, this means that when power is lost before the data is actually written to the magnetic media, the data will also be lost from the disk buffer. Again, kaput. From personal experience I have seen professional photographers lose entire photo collections just because they didn’t take the time to safely eject their drives.

Eject, eject, eject

The solution is pretty simple: eject. So if you have to choose between yanking out your drive and spending an extra 10 seconds and ejecting it, do yourself a favor and spend those 10 seconds. Like the old saying goes, “haste makes waste”. The few seconds it takes to click “eject” is time well spent.XP

Flash drives usually don’t suffer from these issues (as they contain flash memory) and not spinning drives. Just to be safe, always eject it too lest when you remove a flash drive – it might not have finished writing to the drive. (Windows tries to recognize flash drives so it doesn’t write-cache on them, but sometimes it makes mistakes). This is rare, but it never hurts to eject first. Fighter pilots do it. You can do it too.



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