Does pulling out USB flash drive instead of safely ejecting it cause any problems?

Does it really spell doom for the USB flash drive if you just pull it out

Your computer will often display a scary warning if you fail to safely eject the USB drive or USB flash drive. But do you actually still need to do this? What happens if you don’t?

Is there any harm to be incurred by just pulling a USB flash drive out? Why do we need safe removal at all?
We have all been guilty of ripping our USB flash drives out of our computers instead of ejecting them properly, only to receive the judgemental pop up telling us we really shouldn’t have done that.

But when everything on the USB flash drive works fine next time you plug it in, you can’t help but doubt: does it actually do anything when you safely eject your USB flash drives before removing it?

Well, we’ve done a little background study, and it turns out that it does. In fact, waiting those extra 30 seconds to safely eject your USB flash drive could help to properly save your data and software.

Previously, operating systems treat USB flash drives as items that can be trusted not to change state unexpectedly. When reading or writing files, the OS expects the files to remain available and not suddenly vanish in mid-read or mid-write.

If a file is open, a program reading the file expects to be able to return to it and continue reading. Similarly, write orders may be dispatched to a writing subroutine and forgotten by the main program. If a USB flash drive disappears between the times the subroutine is called and the data is written to USB flash drives, that data is lost eternally.

In the olden days, there were official processes to physically “mount” and “unmount” storage USB flash drive, and the physical act of mounting a tape or a USB flash drives pack triggered some mechanical switch to identify the presence or absence of USB flash drive. Once the mechanism was engaged, the software could start to use the USB flash drive (a “soft mount.”). Some media and USB flash drives even had mechanical interlock to avoid media on the USB flash drives from being expelled or removed until the software processes using the media free the lock.

As Phillip Remaker explains over at Quora that our operating systems have been programmed to treat our external USB drives like USB flash drives – like they’ll always be there. It expects the files on it to remain reachable indefinitely and these changes the way it interacts with a USB flash drive.

This means if a program on your computer is just reading a file and not actually saving any information to the USB flash drive, it’s probably not going mess things up too much for the files on your USB flash drive if you suddenly pull it out. But you do risk confusing your computer, says Remaker. “Symptoms could include: Lost data, corrupted file systems, crashing programs, or hanging computers requiring a reboot.”

The Macintosh floppy and optical disk provide more current examples of an interlocked physical and soft mount. One could only eject USB flash drive through a software command, but that command might fail if some program was holding a file open on the medium. Enter USB flash drive connected storage. There is no mechanical interlock in a USB connection to coordinate the hard and soft mount. The user can decide to rip the USB flash drives out from under the operating system at any time, and endure all manner of programs freaking out about the sudden loss of media from the USB flash drive. “Hey! I was using that!”

A safe removal does a few things like it flushes all active writes to USB flash drive, alerts all programs (that know how to be alerted) that the USB flash drive is going away, and to take suitable action and it alerts the user when programs have failed to take action, and still are holding files open.

You can remove a USB flash drive at any time, but you are at the pity of how well programs using the disk manage with the sudden disappearance of that USB flash drive.

In the new computer, many steps have been taken to protect against the unpredictable and casual removal of USB flash drives. For example, Windows even introduced a feature called “Optimise for Quick Removal” that makes sure data is written quickly instead of batched up and written professionally. It is very hard to get people to change habits. If you are doing exclusively reads on a USB flash drives, safe removal is perhaps not needed. If you are doing writes, you are probably OK to skip safe removal if you haven’t written recently and you aren’t doing something silly like indexing that USB flash drive.

As a good friend of mine once said: Life is too small to safely eject the USB flash drive.

However, Safe Removal does a number of essential things and is, in fact, the only assuredly secure way to remove a USB flash drive. You probably don’t need it most of the time, but it is a good habit to have since data loss sucks.


How do I safely remove a USB flash drive from my computer?

Safely removing the USB flash drive from the computer
How do I safely eject my USB flash drive from the computer?
Windows 7 or Vista
1. Right-click the Removable Disk or USB flash drive you want to remove.
2. Select Eject to safely remove the USB flash drive.
Image3. Wait for the Safe to Remove Hardware message to appear, then unplug the device or USB flash drive from the USB port.
ImageWindows XP
1. Click the Safely Remove Hardware icon on the system tray.

2. Select a device or USB flash drive to remove.

3. Wait for the Safe to Remove Hardware message to appear, then unplug the device or USB flash drive from the USB port.

Mac OS X
Simply drag the Removable Flash Drive icon to Trash, then unplug the device or USB flash drive from the computer.

Or Safely Remove USB Flash Drives Just by Unplugging Them

Most Windows users have become conditioned over time to never unplug a USB flash drive or USB hard drive without first clicking Safely Remove Hardware in the System Tray.

Why is that necessary? In theory, it’s to ensure that Windows isn’t busy reading from or writing to the USB drive when you remove it, something that could result in corrupted data or even a damaged USB drive.

As it turns out, however, you can safely sidestep Safely Remove Hardware with little to no loss of performance. In fact, this option may already be enabled on your system, and you just didn’t know it. Yep, you may have been wasting extra clicks all this time.

Do this:

1. Plug your USB flash drive into your PC, then open Device Manager. (Note: These steps are based on Windows 7. Things might look different in previous versions of Windows.)

2. Expand Disk Drives, then find the entry for your removable USB drive. On my system, for example, it’s called “USB2.0 Flash Drive USB Device.”

3. Right-click that entry, then click Properties.

4. Click the Policies tab; you should see something like this:

5. If the first option, Quick removal, is already selected, you’re good to go. As noted in its description, “you can disconnect the device safely without using the Safely Remove Hardware notification icon.” If Better performance is selected, switch to Quick removaland click OK.

So, what are giving up by disabling write caching? According to the test results posted at 7tutorials, almost nothing. The performance impact was negligible. Your mileage may vary, of course, but I think it’s worth a few milliseconds to avoid the hassles of having to mess with Safely Remove Hardware all the time.

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