It belongs to a mobile storage device, which is used for backing up data and is convenient to carry.
U disk is a kind of flash memory, so it is also called flash disk.
It is characterized by small size, portability, large storage capacity and low price.
Generally, the capacities of USB flash drives are 1G, 2G, 4G, 8G, 16G, 32G, etc. Take the most common 2G as an example, you can buy it around 65 yuan.
At present, the capacity of USB flash drives has been greatly improved, such as 4G and 16G USB flash drives.
It is easy to carry. We can hang it on our chests, on key chains, or even in our wallets.
Angry Frog Network Planning Agency believes that the U disk is actually a mobile hard disk, but technology will always serve the convenience of human beings. Designers will shrink the huge hard disk into a small piece, which is more conducive to human carrying and application. In this respect, technology has facilitated human life, which is not bad.
Nowadays, USB flash drive can replace CD-ROM drive as a new tool for system installation. In the domestic Internet, the installation of U disk system tools is an outstanding star in this field.
From the perspective of system attributes, the specification constitutes USB-related hardware and its equipment. In the USB specification, it is divided into five parts, namely controller, controller driver, USB chip driver, USB device and client device driver for different devices.
Controller (host)
Controller): This is a physical chip, which is mainly responsible for executing the commands issued by the controller driver.
At present, almost all controllers are integrated on the south bridge chip of the motherboard, and users do not need to operate alone.
Controller driver (host
controller
Driver): Establish communication link between USB and controller.
USB chip driver (USB
chip
Driver): Support USB.
USB device (USB
Device): USB peripheral devices connected to a PC, including USB hubs and devices.
The former can be connected with other USB devices, and the latter is a specific device for completing specific functions.
Client device driver (client
Driver): a driver used to drive USB devices, usually made by USB device manufacturers or systems.
Transmission mode control mode transmission: control transmission is bidirectional transmission, and the data volume is usually relatively small.
USB system software is mainly used to query, configure and send general instructions for USB devices.
The transmission mode can include 8, 16, 32 and 64 bytes of data, depending on the USB device and the transmission rate.
Control transmission is usually used for transmission between the host and USB peripheral devices.
Synchronous _ asynchronous _ mode transmission: Synchronous transmission has a certain bandwidth and delay.
It is used for streaming data transmission with strict time requirements and strong fault tolerance, or for real-time applications requiring constant data transmission rate.
For example, when realizing VoIP application of instant messaging, synchronous transfer mode is a good choice.
Synchronizing data requires a certain bandwidth value and a certain maximum number of transmissions.
For synchronous transmission, real-time data transmission is more important than perfect accuracy and data integrity.
Interrupt _Interrupt_ mode transmission: Interrupt mode transmission is mainly used to periodically query whether the device has interrupt data to transmit.
The structure of the device's endpoint modeler determines its query frequency, ranging from 1 ms to 255 ms
This transmission mode is usually used to transmit small, scattered and unpredictable data.
Keyboard, sidebar and mouse all belong to this type.
Interrupt mode transmission is one-way, and the host only has input mode.
Batch transmission: it is mainly used to send and receive a large amount of data, which requires guaranteed transmission, without bandwidth and interval requirements.
Printers and scanners belong to this type.
This type of equipment is suitable for very slow and delayed transmission, and can wait until all other types of data transmission are completed before sending and receiving data.
Storage principle of USB interface
The computer converts the binary digital signal into a composite binary digital signal (adding instructions such as allocation, check and stack) and reads it into the USB chip adapter interface. The chip processing signal is distributed to the corresponding address of EPROM2 memory chip to store binary data, thus realizing data storage.
The control principle of EPROM2 data storage is that the voltage controls the voltage of the gate transistor, and the junction capacitance of the gate transistor can store the voltage value for a long time, which is why USB can store data after power failure.
Can only be explained in such a simple and popular way.
Usage U disk U disk has a USB interface and is a USB device.
If the operating system is Windows
In the case of 2000/XP/2003/Vista or Apple system, the system will automatically identify the U disk by inserting it directly into the USB interface on the front panel or the back of the chassis.
If the system is 98, you need to install a USB flash drive to use it.
You can find the driver on the attached CD or the manufacturer's website.
When you first use the USB flash drive, the system will report and find new hardware. After a while, you will be prompted that the new hardware has been installed and can be used.
Open "My Computer" and you will see an additional icon named "Removable Disk".
After this step, if you use a USB flash drive in the future, you can directly open "My Computer".
At this point, notice that a small icon will appear in the lower right corner of the screen, indicating a USB device.
(U disk is one of USB devices),
Next, you can save and delete the files on the USB flash drive as usual.
However, it should be noted that after using the USB flash drive, close all windows, especially those about the USB flash drive. Right-click the USB device icon in the lower right corner before correctly unplugging the USB flash drive, then left-click "Remove Hardware Safely", press the "Stop" button, and then click "OK" in the pop-up window.
When the prompt "You can safely remove the drive now" appears in the lower right corner, you can unplug the USB flash drive from the chassis.
History of Invention When U-disk replaced floppy disk as people's conventional mobile storage tool, few people knew that U-disk was not a product name, but only a flash disk trademark registered by the company.
The company that invented the world's first flash drive and obtained the basic invention patent of the global flash drive, its founder and one of the invention patent holders, Lu, president of Harbin Netac Technology Co., Ltd., settled in the Pioneer Park for Overseas Students in Harbin Development Zone at the beginning of his business, and led the development trend of the global mobile storage industry together with Shenzhen Netac Company.
Netac's OnlyDisk, with the U disk as its trademark, is the world's first one based on USB interface and using Flash.
Memory) media is a new generation of storage products.
USB flash drive is the only original invention patent in the field of computer storage in China in recent twenty years, which belongs to China people.
Precautions for use 1.
U-disk generally has a write-protection switch, but it should be switched before it is plugged into the computer interface, and it should not be switched when it works.
2.
The USB flash drive has a working status indicator. If it is an indicator light, when it is plugged into the host interface, the light will light up, and when it flashes, it means that data is being read and written.
If there are two indicator lights, there are generally two colors, one is on when the computer is turned on, and the other is on when the USB flash drive reads and writes data.
After the system copy progress bar disappears, some USB flash drives are still working. It is forbidden to pull the USB flash drive when the read-write status light is on.
Do not unplug the USB flash drive until the reading and writing status indicator light stops flashing or goes out.
3. Some brands and models of USB flash drives have little space reserved in the file allocation table, and it is easy to report errors when copying a large number of single small files. At this time, you can stop copying and adopt the method of compressing multiple small files into one large file.
4. In order to protect the USB interface between the motherboard and the USB flash drive, prevent deformation and reduce friction, try to use the USB extension cable, which is generally given with the USB flash drive.
If you need to buy, try to choose famous brands, and the thicker the lines, the better.
But it can't exceed 3 meters, otherwise it is easy to make mistakes when copying data.
5.
The storage principle of U disk is very different from that of hard disk, so there is no need to defragment it, otherwise it will affect its service life.
Troubleshooting and maintenance should eliminate the following faults: first, the USB interface is damaged, the PCB board is welded, and the USB extension cable is normal, and then the maintenance judgment is made.
1.The USB flash drive does not respond when inserted into the machine. Maintenance ideas: According to the fault phenomenon, the whole U disk does not work, and the conditions required by the U disk tools are the focus of our maintenance.
The USB FLASH drive of any scheme must meet the following conditions if it wants to work: (1) power supply, which is divided into power supply needed by main control and power supply needed by flash. These two are keys, and the circuit of the USB flash drive is very simple. If there is no power supply, it is generally the fuse inductor or the 3.3V voltage stabilizing block that is damaged. Speaking of voltage stabilizing block, I'll talk about it here. It has three pins, namely power input (5V), grounding and power output (3.3).
3.3V .
As long as we find a place without power supply, this problem will be well solved.
(2) Clock, because the host can only work at a certain frequency, and the communication with FLASH also needs a clock signal for transmission, so if there is no clock signal, the host will definitely not work.
When checking this circuit, in fact, the clock generation circuit is very simple, just check the crystal oscillator and its peripheral circuits, because the crystal oscillator is afraid of rubbing and the U disk is easy to fall to the ground, which will damage the crystal oscillator, so just replace the same crystal oscillator.
Note: the crystal oscillator cannot be measured, and the best way to judge its quality is to change a good crystal oscillator.
(3) Master control. If the above two conditions are normal, the master control chip is damaged.
Just change the main control.
2. Insert the USB flash drive into the computer and prompt "Unrecognized device".
Maintenance ideas: for this phenomenon, first of all, it shows that the circuit of the U disk is basically normal, but there is a fault in communication with the computer. For communication, there are the following points to check: (1) USB interface circuit, no special components, only two data lines D+
D-, so when checking this circuit, you only need to measure whether the line between the data line and the main control circuit is normal. Generally, two resistors with smaller resistance will be connected in series between the data line and the main control circuit for protection, so it is necessary to check whether the resistance values of these two resistors are normal.
(2) Clock circuit, because the communication between the USB flash drive and the computer should be carried out at a certain frequency. If the working frequency of the USB flash drive and the computer can't be synchronized, then the system will think that this is an "unrecognizable device".
At this time, the crystal oscillator will be changed.
And there are many examples of crystal vibration damage in actual maintenance! (3) Host, if the above two checks are normal, it can be judged that the host is damaged.
3. You can recognize the USB flash drive, but when you open it, you will be prompted "The disk is unformatted" but the system cannot format it, or you will be prompted "Please insert the disk". When you open the USB flash drive, it's full of messy things, and the capacity doesn't match your own.
Maintenance ideas: for this phenomenon, it can be judged that there is not much problem with the hardware of the U disk itself, but there is a problem with the software.
Solution: Just find the repair tool of the master control scheme.
This depends on everyone, what is the main control scheme of the USB flash drive.
The failure of U disk is generally due to the poor performance of flash memory or the phenomenon that bad blocks can't be written and stored in files.
Unlike MP3, USB flash drives don't have firmware, but some manufacturers put their own software in them. If they are low, they will be gone.
Tell you a very simple method, that is, when the main control is damaged or the corresponding repair tool can't be found, you can use the USB flash drive kit to make a new USB flash drive. The method is to remove the flash of the faulty machine and put it on a new PCB.
U disk kit includes (PCB with main controller (1. 1/2.0) and a set of shell), which is very simple to maintain and more convenient for data recovery.
Life The erasable times of a USB flash drive are the normal life of the USB flash drive. Generally, the U disk with MLC particles can be erased more than 1000 times, while the life of the U disk with SLC particles is as long as 1000 times.
Maintenance of USB flash drive Insert and unplug USB flash drive correctly: Never pull out USB flash drive when the indicator light of USB flash drive flashes rapidly, because USB flash drive is reading or writing data at this time, and pulling it out halfway may cause damage to hardware and data.
Don't close the related program immediately after backing up the document, because the indicator light on the U disk was still flashing, indicating that the program was not completely finished. At this time, pulling out the USB flash drive will easily affect the backup.
Therefore, after the file is backed up to the U disk, it will take some time to close the relevant programs to prevent accidents; Similarly, when the system prompts "Cannot stop", don't pull out the USB flash drive easily, which will also cause data loss.
Pay attention to place the U disk in a dry environment, and don't expose the interface of the U disk to the air for a long time, otherwise it will easily cause surface metal oxidation and reduce the sensitivity of the interface.
Don't always plug a long-term unused U disk into the USB interface, otherwise, on the one hand, it will easily lead to aging of the interface, and on the other hand, it will be a loss to the U disk.
With the wide application of mobile storage devices such as USB flash drive, mobile storage has become one of the main ways of virus transmission and parasitism.
Related protection measures have also appeared, the most common is to ban the automatic playback function and use tools to protect it.
So let's talk about another method today. After all, there are many ways to go, and everyone can choose the one that suits them.
First, click the Start menu, open the running box, enter gpedit.msc, open the group policy, click Computer Configuration-"Windows Settings-Security Settings Software Policies Other Rules", right-click other policies, select New Path Rule, and enter in the pop-up rule box:
The drive letter of the USB flash drive is. EXE, and the path of the U disk on my machine is H:, so enter "H:". EXE "and select" Not allowed "as the security level, which means that all EXE programs under H: are prohibited from running.
Okay, it's that simple. Now, if we double-click any EXE executable file on the U disk, a warning box will pop up.
Of course, the current virus is also very smart, and sometimes the extension is changed to. COM or. BAT, and we can also list them in the group policy in the above order.
In this way, we can keep the only way for the U disk virus to enter the computer.
Viruses are prohibited from running in NTFS format. The virus source file that can't be cleaned may be running, and there is no security tool around to find out its process or forcibly delete it. What should I do?
Tip: Right-click the virus file, select Properties-Security, delete all groups and users except administrators, then select the administrator group or user, click Advanced below, select the administrator in the permission bar, click Edit to enter the permission item of the program, and change all other items except deletion to Reject. Click OK before restarting the machine.
In this way, the virus program can't be started again, and we can easily delete it.
Repair Now, the use of USB flash drives has become very common, and people often use USB flash drives to back up, carry and transfer files.
However, if you forget to uninstall the U disk before pulling it out of the USB port, or uninstall it incompletely, or pull it out of the USB port directly due to misoperation, it may lead to the damage of the U disk, and sometimes even cause the computer to fail to recognize the U disk.
If you have no experience in dealing with this situation before, most people will think that the USB flash drive is no longer usable and should be thrown into the trash can, but it is a pity.
Is there any way to restore the function of the USB flash drive? The answer is yes. You can follow the following steps: Open Control Panel-Administrative Tools-Computer Management-Storage-Disk Management in turn, right-click the text "Disk 1", select "Initialize Disk" and click "OK" directly.
After the initialization is completed,
The status of the USB flash drive changes to Online.
Pay attention to the lock of the U disk at this time, otherwise the following prompt will appear: "The requested operation cannot be completed because the media is write-protected.
"
Right-click the white box on the right and select "New Disk Partition" to enter the New Disk Partition Wizard. Click Next directly and select the partition type (primary partition, extended partition or logical drive). Usually, you can choose the primary disk partition.
(Note: The following dialog boxes will appear in sequence, so screen copies of them are not given here.
) 1. Select disk space capacity: generally use the default size.
2. Assign (or not assign) a drive letter.
3. Select "Format this partition according to the following settings" to set the format (file system type, allocation unit size, volume label) (quick format is not required).
4. Successfully completed the formatting wizard.
Click Finish and wait for its formatting to complete.
After the formatting is completed, the status of the U disk is displayed as "intact", that is, you are done.
This method can generally restore the USB flash drive.
However, this method also has a disadvantage, that is, it cannot restore the original data on the U disk.
This method is more useful if the original data on the USB flash drive is not very important.
If there are very important files on the USB flash drive, you must restore them. It is recommended to find a professional company.
Now major cities basically have professional companies to do data recovery!
Related knowledge startup mode If you want to use a USB flash drive, you must simulate the above related devices, so there are various startup modes now:
1.usb-zip: The letter of the U disk is A after starting the drive mode.
2.USB-FDD: After the floppy drive mode is started, the drive letter of the U disk is A..
3.USB-HDD: After the hard disk mode is started, the drive letter of the U disk is C; (Note: This mode is easy to screw up when installing the system, because you are afraid of confusing the U disk with the C partition of the hard disk when you are dizzy. )
4.USB-CD-ROM: After starting the CD-ROM mode, the drive letter of the U disk is of course CD-ROM.
ZIP and HDD modes are popular at present, which are simple and easy to use. As for FDD, it has already withdrawn from the historical stage.
U disk, USB interface and plug-and-play U disk In layman's terms, USB is one of the interface types between peripheral devices and computer hosts.
In addition to USB interface, there are parallel bus and other interfaces.
However, USB interface has a great advantage that makes it very popular in this field, that is, devices with this interface can be plugged and played on computers (sometimes called hot plug).
When the computer is turned on, the peripheral equipment should be turned on first, and then the power of the host computer should be turned on, and the order of turning off is just the opposite.
The reason why this boot sequence should be followed is that before the computer starts, all peripheral devices must be powered on to get ready, and then wait for the host to check these devices one by one and install the corresponding software.
Only in this way can the computer run normally, otherwise the peripheral equipment may be unavailable or the computer can't recognize the peripheral equipment.
However, the appearance of USB interface changed this situation. If a device is a USB interface, it can be plugged into the computer host at any time, no matter what state the computer is in at this time. If you want to take this device with you, just follow the instructions to safely remove it from your computer.
This undoubtedly brings great convenience to people's study and life.
Therefore, from the name of the U disk, we can see that this storage disk is USB interface, because this storage disk is USB interface, so this storage disk can be inserted into a computer to play, which means that this storage disk is a mobile storage disk and can be carried around.
Therefore, in a broad sense, a U disk actually refers to a mobile storage device.
In a narrow sense, U disk only refers to USB flash drive.
Flash disk refers to a mobile storage disk that uses flash technology to store data information.
Flash memory technology is a storage technology that has just emerged in the computer field for several years.
Compared with the traditional electromagnetic storage technology, it has many advantages: first, this storage technology has no mechanical movement in the process of storing information, which makes it run very stably, thus improving its seismic performance and making it the most anti-vibration device among all storage devices.
Second, because it doesn't have high-speed rotating disks like floppy disks, hard disks and optical disks. Its volume can usually be made very small.
The reason why MP3 players can do very little now is because of this storage technology.
For example, some people say that he has a USB flash drive, which may be just an ordinary mobile hard disk, or a micro hard disk that has just appeared in recent years, or a USB flash drive.
Of course, as mentioned above, the current USB flash drive generally refers to a USB flash drive, so we usually understand that what he owns is a USB flash drive.
prospect
ReadyBoost
ReadyBoost is windows.
A new technology in vista uses the advantages of random reading and writing of flash memory and reading and writing of fragmented files to improve system performance.
If your USB flash drive meets the specifications, you can speed up the system by starting ReadyBoost.
Online storage-"network USB flash drive" has the functions of "upload" and "breakpoint continuous transmission", which not only realizes large files, but also has the function of breakpoint continuous transmission, which can transmit files in segments and greatly save transmission time.
but
Upload/
Slow speed, not practical for files over 200M m m.
"u disk parasite" (Checker/Autorun)
"U disk parasite" is a worm virus spread by mobile devices such as U disk, which automatically plays files by autorun.inf.
Autorun.inf file generally exists in the root directory of USB flash drive, MP3, mobile hard disk and hard disk partition. When a user double-clicks a device such as a USB flash drive, the file will use the automatic playback function of Windows system to execute the virus program to be loaded first, thus damaging the user's computer and causing losses to the user's computer.
Suggestion: Before using the USB flash drive, users must scan it with anti-virus software and confirm that it is non-toxic before opening it.
The data transmission speed of brands and USB flash drives is generally related to the data interface and the quality of USB flash drives, because the use of USB flash drives, unlike the storage speed of hard disks, is only related to the interface type of USB; The USB 1. 1 and USB2.0 standards used to distinguish speeds have been changed to USB2.0.
all
Speed (that is, corresponding to the previous USB 1. 1) and USB.
2.0
high
Speed (that is, corresponding to the previous USB2.0) In addition, there is USB2.0.
Normar
speed
The transmission speed is very slow, and it is usually used on keyboard and mouse. These standards may also be displayed in some testing software as follows.
USB2.0
(FS) and
USB2.0
(HS), so it must be confirmed that it is the interface of HS. If the unified USB2.0 does not indicate the speed, it must be tested on site. Generally speaking, the speed of HS can reach 5~ 10M/S, while the speed of FS is below 1M/S, which is easy to distinguish.
Introduce several popular U disk brands: LG, Sandisk, Kingston, Patriot, Amber, Bolos, Jinbang, Netac, Lenovo, BenQ, Newman, Tsinghua Hi-Tech, Ziguang, Digital China, Ziming, Ubuntu, IBM and Taipower.
But yes, because the work of memory is very simple, the core is just a flash memory. In addition, flash memory is basically manufactured and sold by Hyundai and several other factories around the world.
The memory particles themselves are of good quality.
Therefore, memory is generally no different from any brand, and it is basically not bad.
The only difference is that the products of big factories may read and write faster and have better after-sales service.
It is not necessary for us. Just stick it in for a second. Why spend tens of dollars more?
At present, the inferior brand memory on the market is generally guaranteed for one month or one year, which shows that the quality is still very good.
Don't drop it as long as it doesn't get into the water. It won't break.
Various functions of u disk
The first kind of advertising flash drive: advertising flash drive, that is, the reader prestores the website address of a business website, which has all the functions of ordinary flash drive. When the U disk reader of the website is plugged into the USB interface of the computer, the computer will automatically input the website address of the merchant website immediately.
The second category: the customer's LOGO can be processed by digital color printing to form various color effects, and can also be processed by matt and bright effects.
Very beautiful!
Startup USB flash drive: a functional USB flash drive specially used for system startup. When the computer can't be turned on normally for a while, it is relatively simple to enter the system for related work.
The second category: the computer city or computer technicians specially use the powerful USB flash drive to maintain the computer, which can not only start the computer.
It can also perform disk partition, system antivirus, system repair, file backup, secret modification and other functions.
It is more suitable for technicians, and some functions such as one-button installation system can be added.
Luminous u disk
The first category: this kind of USB flash drive can add a special luminous material to the USB flash drive shell, which is similar to the effect of luminous glow sticks.
Simple but practical.
The second type: this USB flash drive leads out a set of power supply circuit through the PCB of USB flash drive to supply power to light-emitting devices. There are many kinds of light-emitting devices, including LED lights, LED screens, and small light cannons (but this kind is relatively rare).
This USB flash drive can only shine if it is plugged into a computer.
The first encryption U disk: hardware encryption technology, generally using the U disk shell to install secret devices. This kind of USB flash drive, like the secret box we use every day, is generally made of ABS or metal, which plays a certain protective role.
The second category: software encryption technology, which mainly relies on programmers to write various encryption software to encrypt the U disk. Generally, the program is written into a USB flash drive through mass production tools to prevent formatting and deletion. , and can only be completed if the correct password is entered.
Waterproof u disk Waterproof u disk: This kind of u disk is rarely sold in the market.
Generally high-end luxury goods, only for business people.
General process waterproof: the shell is waterproof, and USB is isolated from PCB.
The first kind of temperature measuring U disk: This kind of temperature display is to install a software on the computer to detect the temperature in the U disk and sense the temperature obtained by the U disk through the software.
This method relies on computer software to test the temperature.
The second method: This method directly packages the hardware for testing temperature in a USB flash drive and displays it directly on the output LED screen of the USB flash drive.
Software is encapsulated in hardware.
Music USB flash drive
Music USB flash drive has all the storage functions of USB flash drive, and also has the function of playing music files.
The appearance of ordinary music USB flash drive is the same as that of ordinary USB flash drive. The difference is that it has a built-in battery and an extra jack for connecting the equipped headphones. After plugging in, you can listen to music in common formats such as MP3 and WMA, support the selection of up and down music, and set the random play function.
The advantage of music USB flash drive is that compared with ordinary USB flash drive, it has the function of playing music, while compared with MP3, it has the advantages of low cost and material benefit, and it is a new generation of mobile storage product that extends and develops the function of USB flash drive.
Anti-virus USB flash drive
Anti-virus USB flash drive is a kind of USB flash drive embedded with various anti-virus software, which makes the anti-virus software easy to use, safe and simple.
After connecting to the USB interface of the computer, it will be recognized by the host without complicated installation.
A new drive letter will automatically appear under "My Computer".
Anti-virus u disk version runs automatically.
Anti-virus USB flash drive can be divided into write type and embedded type in performance.
Write-in antivirus program can only play the role of antivirus if it is installed in the computer; The embedded antivirus program is written in the control chip of the USB flash drive, so it can be disinfected at any time without installation.
U disk system U disk system is the product of U disk as a new function, which is active in the IT field. It replaces the complicated system installation method of traditional CD-ROM drive, inherits the system installation program to a small U disk as the startup tool and system carrier for system installation, and then installs the system on the computer.
At present, there are many websites of U disk system startup tools in China, so please install them.
As a rising star in this field, with safe and convenient professional technical support, it is increasingly favored by users.