USB Mass Storage includes USB Flash Drive which are devices that go beyond a built-in data storage and removable media and now some has extra added features. Many confuses between USB mass storage device and USB Flash Drive. USB Flash Drive also known as Pen drive. Technically we will describe USB Flash Drive, however USB Mass Storage will be compared to make understand the difference.
Difference between USB Mass Storage and USB Flash Drive
USB mass storage is a device class, the device class is a protocol that allows a Universal Serial Bus (USB) device to become accessible to a computing device, to enable file transfers between the two. USB Mass Storage includes USB Flash Drive or pen drive as well as digital cameras, Android tablets, mobile phones – any device which actually has a memory card or bult in flash memory. However in broad sense, USB Mass Storage and USB Flash Drive is used synonymously by the layman.

Technical details of a typical USB Flash Drive ( USB Mass Storage , Pen Drive)
Due to higher storage capacity and access speed of any USB Mass Storage and ease of use they have replaced CD-RW and Iomega Zip Drive like removal media. Memory system is usually a flash memory .
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Much faster USB 2.0 USB Mass Storage device and USB 3.0 USB Mass Storage can theoretically have transfer rates of up to 30-35 MB / s. For USB devices, there is no locking, so that these can always be disconnected from the computer. If this happens to any USB Mass Storage while data is being written to the device, loss of data happens without warning. To prevent this, the operating system has to be notified that the USB Mass Storage device will be removed. After completion of all writing operations to the device the OS outputs a message that the device can be removed.
The design of USB Mass Storage is of USB standard defined plugs. Some USB Mass Storage devices combine the functionality of a digital audio player by integrating firmware and a basic LCD panel, sometimes a Finger Print reader is added.

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