Why you don’t really need to “safely eject” your USB drive

Many PC users will refuse to remove a flash drive or external hard drive from a USB port on their PC without “safely ejecting” it first.

Safely removing hardware is available as a function in multiple operating systems and ensures no data is corrupted or lost after the drive is removed.

Therefore, major operating systems recommend that users safely remove their drives through the OS software before simply yanking them out.

Users of modern hardware, however, will be just fine removing their flash drives from a PC without following this process.

This is because modern PCs and drives are fast enough to prevent serious data corruption caused by processes such as write caching.

Write caching

Write caching is a process used by an operating system to improve its performance when copying or moving files to a USB drive.

The feature is enabled by default on Mac and Linux, but is disabled by default on Windows.

Using write caching, the system writes to high-speed memory before writing to its destination drive to reduce user wait times.

The machine then finishes writing the data from the cache to the external drive in the background, allowing the user to continue with their work.

Telling the OS to safely remove a drive essentially flushes the write cache to the destination drive before notifying the user they can remove the drive.

However, transfers from write cache to the destination drive happen on the scale of milliseconds, making it difficult to lose data by removing the drive – unless you pull it out mid-transfer.

Removing drives

If you remove a USB drive while data is being moved to it, or the write cache is still operating, you could lose data and may corrupt the USB drive.

But you shouldn’t worry about this, as the write cache is not active for very long and you would need superhuman reflexes to pull out the flash drive before the data has been written from the cache to the drive.

According to Harvard School of Engineering and Applied Sciences chief technology officer John Paulson, “the process finishes so quickly that humans who move at regular speed shouldn’t worry about that, unless you’re the Flash”, he told Popular Science.

If you typically remove drives without safely ejecting them via the OS, you should refrain from disconnecting them while copying information. It is also a good idea to wait a few seconds after the data has been transferred before pulling the drive out.

Additionally, Windows 10 optimises all external drive processes for quick removal by default – reducing the chance of data corruption.

If you have the time and are dealing with valuable data, and don’t want to put anything to chance, safely ejecting your USB drive is fine – it just does not make much of a difference.

Now read: New Toshiba SSD uses 96-layer 3D flash memory

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Why you don’t really need to “safely eject” your USB drive