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Eject would normally make sense for CDs, etc., and safely remove tends to be used with USB media. However, my Kindle (which connects over USB) shows distinct behavior when using the two options: After ejecting a Kindle, you can use it normally (i.e., read books), but after safely removing it, it shows the same screen as it did before (i.e., it shows a screen saying roughly “the kindle must be ejected before it can be used”).

So, what is the difference between “Eject” and “Safely remove” on a Windows machine? What is the “intention” associated with the two terms?

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I assume part of the intention is to do with the difference between read only media (which can be safely ejected at any time, and left in a coherent state). Versus read/write media like a USB disc, which might still have pending writes and where immediate removal can leave the media in an inconsistent state. –  cbz Mar 8 '11 at 11:18
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However, my Kindle(which connects over USB) shows distinct behavior when using the two options. Can you explain the difference? –  Belmin Fernandez Mar 11 '11 at 14:10
    
After ejecting a Kindle, you can use it normally(i.e. read books). But after safely removing it shows the same screen as it did before (i.e. it shows a screen roughly saying the kindle must be ejected before it can be used). –  apoorv020 Mar 11 '11 at 18:04
    
@apoorv020 You should include that part in the question itself.. –  Pacerier Jul 5 '12 at 13:18
    
There is a glitch of sorts in some versions of Windows in that if you "eject" a USB device it "ejects" the entire USB controller, and it cannot be used again until you reboot. –  Daniel R Hicks Sep 18 '13 at 15:54

4 Answers 4

up vote 10 down vote accepted

Eject removes the media from the device (e.g., ejects the CD tray) but doesn't remove the device itself.

Safely Remove flushes any pending writes from the cache and removes the entire device.

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What would "removing the media" from a Kindle look like? iow: What you say sounds reasonable, but it doesn't answer apoorv020's question. –  Ian Boyd Mar 11 '11 at 14:44
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Without knowing how the Kindle communicates with the computer - whether it presents itself as a mass storage device, or uses a propriatory system, it is impossible to say. As for answering his question, I believe that was what is the difference between eject and safely remove - which I have done. The Kindle was just mentioned in passing as an example of observed differences (which aren't elaborated on, despite a request for more information) –  Majenko Mar 11 '11 at 14:52
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can you point me to a source for your answer? –  apoorv020 Mar 11 '11 at 18:08
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How do the media and the drive differ in the case of USB drives? I can usually choose to either eject, remove or do both of them. What's the purpose of giving the user the ability to choose one, the other or both? –  Amelio Vazquez-Reina Oct 25 '11 at 23:33
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The 'media' is the filesystem - the 'drive' is the device. In the case of a flash drive they both perform the same function. They provide both for those USB devices with removable media. –  Majenko Oct 25 '11 at 23:58

During the time of Windows 98 there was only one option Eject. Any USB device like pen drive required that the driver for that device be manually installed.

To remove the device you had to select Eject from the context menu.

Since Windows XP the driver gets automatically installed and a new improved feature is provided to remove the USB device which is Safely Remove Hardware.

And as Matt Jenkins said

Eject removes the media from the device (e.g., ejects the CD tray) but doesn't remove the device itself.

Safely Remove flushes any pending writes from the cache and removes the entire device.

Try both the features with a memory card reader.
When you select Safely Remove Hardware the Card Reader device is disconnected from the system while when you select Eject the device is still connected to the computer but you can safely remove the card from the card reader.

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They both make sure all the pending writes to the device are executed, and they both unmount the device afterwards. So I'd say they're the same.

@Matt Jenkins is right, the difference lies with cd-drives where the Eject option only removes de cd, but doesn't remove the cd-drive device. Where as with usb-disks, the behavior is identical.

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As I said in my question, there is a difference in behaviour when I "eject" my kindle as opposed to when I "safely remove" it. –  apoorv020 Mar 8 '11 at 11:25
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@apoorv020: and what exactly might that different behavior be then? –  fretje Mar 8 '11 at 11:26
    
On "safely removing" the device, the drive is unmounted but the kindle cannot be used, while "ejecting" it does both (As far as I have been able to determine) –  apoorv020 Mar 8 '11 at 19:52

@Majenko already answered the Question
Here is some added info

Windows itself tells you that you don’t need to use the Safely Remove Hardware option if you use certain settings – the default settings.

Quick Removal vs. Better Performance

Windows allows you to optimize your USB device for quick removal or improved performance. By default, Windows optimizes USB devices for quick removal. You can access this setting from the device manager – open the Start menu, type Device Manager, and press Enter to launch it.

Expand the Disk drives section in the Device Manager, right-click your device, and select Properties.

Select the Policies tab in the Properties window. You’ll notice that Windows says you can disconnect your USB device safely without using the Safely Remove Hardware notification icon, so this means you can unplug your USB device without ever safely removing it, right? Not so fast.

Data Corruption Danger

The Windows dialog shown above is misleading. If you unplug your USB device while data is being written to it – for example, while you’re moving files to it or while you’re saving a file to it – this can result in data corruption. No matter which option you use, you should ensure that your USB device isn’t in-use before unplugging it – some USB sticks may have lights on them that blink while they’re being used.

However, even if the USB device doesn’t appear to be in-use, it may still be in-use. A program in the background may be writing to the drive – so data corruption could result if you unplugged the drive. If your USB stick doesn’t appear to be in-use, you can probably unplug it without any data corruption occurring – however, to be safe, it’s still a good idea to use the Safely Remove Hardware option. When you eject a device, Windows will tell you when it’s safe to remove – ensuring all programs are done with it. Write Caching

If you select the Better Performance option, Windows will cache data instead of writing it to the USB device immediately. This will improve your device’s performance – however, data corruption is much more likely to occur if you unplug the USB device without using the Safely Remove Hardware option. If caching is enabled, Windows won’t write the data to your USB device immediately – even if the data appears to have been written to the device and all file progress dialogs are closed, the data may just be cached on your system.

EJECT

When you eject a device, Windows will flush the write cache to the disk, ensuring all necessary changes are made before notifying you when it’s safe to remove the drive. Ultimately, no matter which option you use, you should use the Safely Remove Hardware icon and eject your device before unplugging it. You can also right-click it in the Computer window and select Eject. Windows will tell you when it’s safe to remove the device, eliminating any changes of data corruption.*

Note This advice doesn’t just apply to Windows – if you’re using Linux, you should use the Eject option in your file manager before unplugging a USB device, too. The same goes for Mac OS X

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