First, the principle of storage is different.
U disk is a semiconductor material (chip) as a storage unit, also known as solid memory, there is no mechanical part. The removable hard disk is a magnetic medium as a memory, with a mechanical part.
Second, energy consumption is different.
u disk without mechanical parts, need to provide more energy than a small, generally not more than 100mA, while the mobile hard disk energy consumption is relatively large, some time a USB port to provide the current can not be very good to ensure its normal operation, so the mobile hard match a matching data line are able to check two USB ports, You even need to configure a dedicated power supply. This is also the main reason why some mobile hard drives do not work properly.
Three, the volume is different.
This is also the most easy to distinguish the U disk and the difference between the hard disk, U disk than the mobile hard disk obviously a lot smaller, more convenient to carry.
Four, the security is different.
U disk because there is no mechanical parts, so than the mobile hard disk has excellent vibration and humidity performance. But in accordance with the procedures required to operate and use, U disk also want to buy quality, in case there is a problem, data saving than mobile hard disk is more difficult, the data is priceless Ah!
Five, the capacity difference is big.
The current U disk common in the 1G-32G, now the largest has 128G, but compared to the mobile hard disk is still small a lot, but with the progress of manufacturing technology, U disk capacity will be rapid development of new developments.