Support Alert, May 15, 2008
The quick way to safely remove USB drives
Before you unplug a USB device such as a flash drive or external hard disk, you really should use the Windows "Safely Remove Hardware" feature to ensure that Windows has written everything to the device.
That's because Windows, to improve performance, uses a technique called "deferred writes" wherein Windows doesn't always immediately write everything to your external drive each time you use it. Rather, it consolidates lots of small writes into one big write by holding the data in memory.
It's just like washing the dishes; it's far more efficient to do one dishwasher load per day than do a load each time you use a single cup or plate.
But the downside is that some of the data you think you transferred to your USB drive may actually still be in your computer's memory. That's why you shouldn't just pull the drive out but first use the Safely Remove Hardware icon to force Windows to write to the drive anything it is holding in memory.
That's easy enough to say, but the Windows "Safely Remove Hardware" feature is confusing to use, particularly if you have several USB devices. Worse still, the icon often goes missing from the system tray.
"USB Disk Ejector" is a small utility that does the same thing as the Windows "Safely Remove Device" applet, except that it does it quicker and better.
cont here
http://windowssecrets.com/support-alert/2008/05/15/24-The-quick-way-to-safely-remove-USB-drives