write caching and safe removal [Archive] - Glock Talk

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roar
06-23-2009, 14:14
My girlfriend just bought her first external HDD because she is transferring stuff from an old computer to her new one before she sells it.

I was teaching her that you always need to be sure to select "eject drive" before physically disconnecting the drive.

When her new HDD is plugged into her laptop, XP wouldn't show the eject drive option. I just found out how to enable it so she can select eject drive, but in looking at the menu I am not sure if it is necessary to do so.

Under Device Manager, and the settings for the hard drive, it has an option for "optimize for quick removal", which disables write caching and allows you to disconnect the drive without using the safe removal icon.

The second option is "optimize for performance", which would enable write caching and turn on and require the use of the safely remove hardware menu selection.

What, ultimately is the better choice for an external hard drive? I have always been taught to eject a drive before removing it, and as such tell other people to do the same, but now I am not sure what is better.

Thanks!!

Sgt. Schultz
06-23-2009, 19:05
The answer depends on who you ask ... I have been removing all types of drives without ejecting them everyday for years and I've never had any problems with the data. Just be certain that all activity has stopped and that you don't have any files open on the drive when you unplug it.

kc8ykd
06-23-2009, 19:47
Delayed write caching improves write performance by the computer basically storing some of the data to be written in RAM, if it's too busy to write the data right then for some reason. Handy if you're doing a bunch of writes to the media while doing other cpu intensive things.

The need to hit the eject process when that is enabled is to ensure that all the data still in memory is written to the media (could be a thumb drive or external disk in your example) before it's removal lest it be lost. If it happened, it would show up as corrupted files.


If the disk isn't going to be removed from the system often, I'd suggest leaving write caching on. If it's going to be used more like a portable thumb drive, then I'd leave it off.

If the drive is attached when the computer is shut down while write caching is enabled everything gets written from memory to the device automatically as it turns down all the processes. So, 'ejecting' the device isn't necessary before the shutdown.


I leave write caching on for my external disk, since I don't remove it but maybe once a month and use it basically as additional attached storage.