U disk, the full name is "USB flash disk", and its English name is "USB flash disk". It is a micro high-capacity mobile storage product with a USB interface that does not require a physical drive. It can be connected to the computer through the USB interface to achieve plug-and-play. The name USB flash drive originally came from a new type of storage device produced by Netac, called "USB flash drive", which uses a USB interface to connect. After the USB interface is connected to the computer host, the data on the USB flash drive can be exchanged with the computer. Since Netac has registered patents for equipment with similar technology produced later, it can no longer be called "U disk" and is renamed the homophonic "U disk". Later, the name U disk became widely known because it was simple and easy to remember, and until now, the two have been used in common, and no distinction is made between them. It is one of the mobile storage devices.
Introduction
Its biggest advantages are: compact and easy to carry, large storage capacity, cheap price, and reliable performance. The flash drive is very small, only about the size of a thumb, and extremely light in weight, generally around 15 grams. It is particularly suitable for carrying around. We can hang it on our chest, hang it on a keychain, or even put it in our wallet. General U disk capacities include 1G, 2G, 4G, 8G, 16G, etc. The price is the most common 4Gb, which can be bought for about 40 yuan. There is no mechanical device in the storage, and the earthquake resistance is extremely strong. In addition, the flash drive is also moisture-proof, anti-magnetic, and resistant to high and low temperatures, making it very safe and reliable.
[Edit this paragraph] Storage principle
The computer converts the binary digital signal into a composite binary digital signal (adding instructions such as allocation, verification, stacking, etc.) to read and write to the USB chip adapter interface , the corresponding address assigned to the EEPROM memory chip through the chip processing signal stores binary data to achieve data storage. The control principle of EEPROM data memory is to control the voltage level of the gate transistor. The junction capacitance of the gate transistor can store the voltage value for a long time. The main reason why the data can be saved after power is turned off is that the floating gate and selection are added to the original transistor. gate. A floating shed that stores electrons is formed on a semiconductor where current is conducted in one direction between the source and drain. The floating gate is wrapped with a silicon oxide film insulator. Above it is the select/control gate that controls the conduction current between source and drain. The data is 0 or 1 depending on whether there are electrons in the floating gate formed on the silicon substrate. If there are electrons, it is 0, if there are no electrons, it is 1. Flash memory, as its name suggests, is initialized by deleting data before writing. Specifically, electrons are extracted from all floating gates. All data will be returned to "1". When writing, only write when the data is 0, do nothing when the data is 1. When writing 0, a high voltage is applied to the gate and drain electrodes, increasing the electron energy conducted between the source and drain electrodes. In this way, electrons will break through the oxide film insulator and enter the floating gate. When reading data, a certain voltage is applied to the gate electrode. A large current is set to 1, and a small current is set to 0. When the floating gate has no electrons (data is 1), and a voltage is applied to the drain while a voltage is applied to the gate electrode, a current is generated due to the movement of a large number of electrons between the source and drain. In the state where the floating gate has electrons (data is 0), the number of electrons conducted in the channel will decrease. Because after the voltage applied to the gate electrode is absorbed by the floating gate electrons, it is difficult to affect the channel.
[Edit this paragraph] History of Invention
From 1998 to 2000, many companies claimed to be the first to invent the USB flash drive. Including China's Netac Technology, Israel's M-Systems, and Singapore's Trek. But it was China Netac that actually obtained the basic invention patent for USB flash drives. In July 2002, Netac's "fast electronic storage method and device for data processing systems" (Patent No.: ZL 99 1 17225.6) was officially authorized by the State Intellectual Property Office. This patent fills the gap in invention patents in the field of computer storage in China in the past 20 years. The acquisition of this patent caused great shock in the entire storage industry. Israel's M-Systems, including Israel's M-Systems, immediately filed an invalidation review with the China State Intellectual Property Office, which once became a patent dispute that shocked both China and foreign countries in the global flash memory field. However, on December 7, 2004, Netac received the flash disk basic invention patent officially authorized by the US National Patent Office, US Patent No. US6829672. The acquisition of this patent finally ended the competition. China Netac is the world's first inventor of USB flash drives.
On February 10, 2006, U.S. time, Netac entrusted American lawyer Morgan Lewis to submit a complaint to the U.S. Federal Court for the Eastern District of Texas, accusing the U.S. company PNY of infringing Netac's U.S. patent (U.S. Patent No. US6829672). In February 2008, Netac and PNY reached an out-of-court settlement. Netac signed a patent licensing agreement with PNY, and PNY paid a patent licensing fee of US$10 million to Netac. This is the first time that a Chinese company has received huge patent licensing fees in the United States. It further proves that Netac is the global inventor of USB flash drives.
Current flash drives support the USB2.0 standard; however, due to technical limitations of NAND flash memory, their read and write speeds are currently unable to reach the maximum transmission speed of 480Mbit/s supported by the standard. The fastest flash drives currently use dual-channel controllers, but they are still far behind the current era of hard drives or the maximum transfer rate that USB2.0 can provide. The current highest transfer rate is about 20-40MB/s, while the general file transfer speed is about 10MB/s. Older 12Mbit/s devices have a maximum transfer rate of only about 1MB/s. Among them, the leaders in the industry include Shenzhen Langke Company, M-Systems Company, and Singapore Trek Company.
[Edit this paragraph]Usage and maintenance
How to use
The U disk has a USB interface and is a USB device. If the operating system is Windows 2000/XP/2003/2008/Vista/win7/LINUX/prayaya Q3 or Apple system, insert the USB disk directly into the USB interface on the front panel or back of the chassis, and the system will automatically recognize it. If the system is Windows 98, you need to install the USB disk driver to use it. Drivers can be found on the included CD or on the manufacturer's website.
The first time you use a USB flash drive on a computer (when you plug the USB flash drive into the USB interface) the system will make a beep and then report "New hardware found". After a while, a message will appear: "The new hardware has been installed and is ready for use." (Sometimes you may need to restart.) At this time, open "My Computer" and you can see an extra hard disk icon. The name is usually the brand name of the USB flash drive. For example, Kingston is named KINGSTON. After this step, if you use the U disk again in the future, plug it in directly, and then open "My Computer" to find the removable disk. At this time, note that there will be a small icon on the far right side of the taskbar, which looks like a gray There is a green arrow next to the thing, which means safe removal of USB hardware devices. (U disk is one of the USB devices). Next, you can save and delete files on the U disk as you usually do with files, or send files directly to the U disk by right-clicking. However, please note that the U disk is used up. Finally, close all windows related to the U disk. Before unplugging the U disk, double-click the Safely Remove USB Hardware Device icon in the lower right corner with the left button, select "Stop" and then left-click "OK". When the prompt "The USB device can now be safely removed from the system" appears in the lower right corner, you can unplug the USB flash drive from the chassis, or click the icon directly and click "Safely Remove USB Device"
Then wait for the prompt to unplug the USB flash drive from the chassis.