USB Flash Drive

• What is a USB flash drive

USB flash drive , is a USB interface without a physical drive of the micro high capacity mobile storage products, the main purpose is to store data.

It is mainly composed of shell and movement, through the USB interface and computer connection, plug and play, use is very simple and convenient, and it has good security. It is used to store personal data, repair computers, manage systems and carry applications to other computers.

USB Flash drives are small, but they have a lot of storage capacity, relatively speaking. Early flash drives were small, holding 16-32 megabytes of files, and even that was 10-20 times the capacity of floppy disks on erasable mobile storage media that were common at the time. With the development of science and technology, the capacity of USB flash drives has soared according to Moore's Law. By 2012, 4G capacity USB disk has been basically on the edge of elimination, mainstream USB disk capacity has developed to 8-16G, equivalent to 2-4 DVD disc capacity. The maximum capacity has reached 1 terabyte, equivalent to the capacity of more than 240 DVDS.

storage principle
The computer converts the binary digital signal into the compound binary digital signal (adding the instructions of allocation, checking, stack, etc.), reads and writes the binary signal to the USB chip adapter interface, and stores the binary data through the chip processing signal assigned to the corresponding address of the EEPROM memory chip, thus realizing the data storage. EEPROM data memory, its control principle is voltage control gate transistor voltage high and low value, gate transistor junction capacitance can be preserved for a long time voltage value, after the power can save the data is mainly in the original transistor to join the floating gate and select gate. A floating gate for storing electrons is formed on a semiconductor in which current is conducted in one direction between the source and the drain. The floating gate is coated with a silicon oxide film insulator. Above it is the selection/control grid that controls the transmission current between the source and drain. The data is 0 or 1 depending on whether there are electrons in the floating grid formed on the silicon substrate. If you have an electron, it's 0, if you don't have an electron, it's 1.

The biggest advantage of U disk is: small, easy to carry, large storage capacity, cheap price, reliable performance. U disk size is small, only the size of the thumb, extremely light weight, generally about 15 grams, especially suitable for carrying, we can hang it on the chest, hanging on the key string, and even put in the wallet. General USB flash drive capacity is 4G, 8G, 16G, 32G, 64G, in addition to 128G, 256G, 512G, 1T and so on. Flash disk without any mechanical device, seismic performance is very strong. In addition, the flash disk also has the characteristics of moisture, magnetic, high and low temperature resistance, safety and reliability is very good.