Flash drives are also commonly called flash drives, USB flash drives, and U disks.

Flash drives are miniature high-capacity mobile storage products with a Universal Serial Bus USB interface that do not require a physical drive. , the storage medium it uses is flash memory storage medium (Flash Memory). The flash drive does not require an additional drive. It combines the drive and the storage medium into one. It can independently store read and write data as long as it is connected to the USB interface on the computer. Can be used to store data files in any format and easily exchange data between computers. The flash drive is small in size and extremely light in weight, about 15 grams, making it particularly suitable for carrying around. There is no mechanical device in the flash drive and it has extremely strong shock resistance. In addition, the flash drive is also moisture-proof, anti-magnetic, and resistant to high and low temperatures (-40°C ~ +70°C), making it very safe and reliable. The use of a flash drive is very simple and convenient. Any computer that supports Windows 98/Windows ME/Windows 2000/Mac OS and Universal Serial Bus (USB) can use a flash drive. The steps are as follows:

1) Plug the flash drive into the computer's Universal Serial Bus USB interface;

2) The system will automatically recognize and generate a removable disk (Windows 98 requires driver installation);

3) You can then use the flash drive just like a floppy disk or hard disk.

Features of flash drives

Flash drives can be used to exchange data between computers. In terms of capacity, the capacity of the flash disk is optional from 16M to 2GB, breaking through the limitations of the floppy drive of 1.44M. In terms of reading and writing speed, the flash disk uses a USB interface, and the reading and writing speed is much higher than that of a floppy disk. In terms of stability, the flash drive does not have a mechanical reading and writing device, which prevents the mobile hard drive from being easily damaged by bumps, drops, etc. Some models of flash drives have encryption and other functions to make user use more personalized. Flash drives are compact and easier to carry.

What is the difference between a flash drive and a flash memory card?

Flash drives are directly used in computers and are easy to use; other Flash memory products (CompactFlash, SmartMedia, MultiMedia Memory Card, Memory Stick, Secure Digital Card) require a drive before they can be connected to the computer. .

What is USB2.0?

USB 2.0 is a new version of USB technology. The transmission rate is up to 480mbps, which is 40 times that of usb1.1. Suitable for new high-speed peripherals. It inherits the ease of use of USB 1.1, plug and play, no need to install drivers, and is fully compatible with the USB 1.1 standard. The USB 1.1 devices and cables you have purchased can still be used.

(Note: According to a new standard, USB2.0 can be divided into usb2.0 high speed, usb2.0 full speed, usb2.0 low speed, of which only usb2.0 high speed is truly Original USB2.0)

What are the read and write speeds of USB1.1 and USB2.0 flash disks respectively?

The reading speed of USB1.1 flash disk is generally 630KB, and the writing speed is generally 520KB;

The reading speed of USB2.0 is generally 1.5MB, and the writing speed is generally 1.0MB.

Can I connect a usb2.0 device to the usb1.1 interface?

Yes, but due to the speed limit of USB1.1, the effect of USB2.0 cannot be exerted.

Can USB2.0 and USB1.1 devices be used at the same time?

Yes, usb2.0 devices can be stored with usb1.1 devices.

Can we use usb2.0 devices in os 9.x systems?

Yes, but the driver must be installed; however, these operating systems do not support usb2.0. This device These systems can only work in USB1.1 mode

Can other applications be run when reading and writing flash disks?

Yes.

How many times can a flash drive be erased and written to? How long can the data in the flash drive be saved?

The flash drive can be erased and written 1,000,000 times, and the data in the flash drive can be saved for 10 years

How many flash drives can be connected to a computer at the same time?

Theoretically, a computer can be connected to 127 flash drives at the same time. However, due to the ordering of the English letters of the drive and the number of English letters that the existing drive needs to occupy, the flash drive can only be connected to a maximum of 23. (Except A, B, C), and requires the assistance of USB HUB.

Can the flash disk be used in DOS state

The flash disk supports WINDOWS virtual DOS mode (enter in the attachment after starting Windows). A USB flash drive that supports the startup function can be operated in DOS command mode when the computer is successfully started through the flash drive.

Does the flash drive support WINDOWS 95?

The flash drive does not support the WINDOWS 95 operating system. It is recommended that users upgrade the operating system to WINDOWS98 or above.

How to use flash disk under WINDOWS NT4.0?

No. Because the WINDOWS NT4.0 operating system does not support USB devices, and the flash disk is a USB-based device.

What drivers can the flash drive be used with?

A9 Windows98, Windows ME, Windows 2000, Windows XP, MAC OS, Linux.

Does the flash drive require a driver?

Not required on Mac OS, Windows 2000 or above, a driver is required on Win 98

Can the flash drive be formatted under Windows 98 / Windows 2000 / Mac OS? ?

Yes.

Can the contents of a flash drive be encrypted?

Yes.

Can the flash disk be shared in the LAN?

Yes.

What types of data can be stored on a flash drive?

All computer data can be stored, including files, programs, images, music, multimedia, etc.

Do I need to shut down my computer when installing the flash drive?

No, the flash drive is a plug-and-play product and can be plugged and unplugged.

Are flash drives waterproof?

The flash drive is an electronic product. If it falls into water, it may cause an internal short circuit and damage the flash drive.

What precautions should be taken when plugging and unplugging the flash disk?

When the flash disk indicator light flashes quickly, that is, when the computer is reading and writing from the flash disk, do not unplug the flash disk; After inserting the flash drive, it is best not to remove it immediately. In particular, do not repeatedly plug and unplug quickly, because the operating system requires a certain response time, and the interval should be more than 5 seconds.

Can flash drives be infected with viruses?

Flash drives, like all hard drives, can be infected with viruses

When a flash drive is used on a desktop computer and the USB port is on the back of the computer, is there any way to make it more convenient?

Connect to the computer through a USB adapter cable (with A-Type Plug and A-Type Receptacle)

What does the LED light display of the save mean?

When the LED light is on, it means that the flash disk is connected successfully and there is no data transmission for the time being. When the LED flashes, it indicates that the flash drive is in the process of data transfer.

When the LED of the flash drive is still flashing, can I remove the flash drive?

No. The data on the flash disk will be lost or the FAT table will be damaged and a blue screen will appear. It causes the computer to blue screen when the operating system reads the flash drive.

The files on the flash drive are garbled or the files cannot be opened

Use special tools for flash drives to format them.

When double-clicking the flash drive letter, the computer prompts that the flash drive needs to be formatted

The above phenomenon will occur when the flash drive partition table is damaged or the flash drive performance is unstable. When this kind of problem occurs, you can generally use a special tool for flash disks to format it.

The flash disk write protection does not work, and data can be written smoothly even when the write protection is off.

Switching the flash disk write protection switch needs to be disconnected from the computer. If the write-protect switch is switched while connected to the computer, the flash drive needs to be re-inserted and unplugged for the switch to take effect.

What should I do if the drive letter is not seen when the USB flash drive is inserted under Windows 2000, or the drive letter does not disappear when the USB flash drive is pulled out?

You need to refresh the screen, or press F5, or right-click the blank space of My Computer, and you will see the "Refresh" option in the pop-up menu

Why do two drive letters appear when inserting a USB flash drive into the computer?

The reasons may be:

1) The U disk may have been partitioned

2) The power supply to the USB port of the motherboard is unstable and the voltage is temporarily too high

3) Shocked by high-voltage static electricity

Treatment method: If it is the first case, please format the USB flash drive; if it is the second or third case, please contact the agent and return it to the manufacturer repair.

Why is the computer not recognizing the U disk after plugging it into the USB port, and no "Removable Disk" appears?

The reasons may be:

1) The USB port is not in good contact.

The solution: unplug it, wait ten seconds and then plug it back into the USB port. The contact is intact;

2) The USB function of the computer is not turned on,

The solution: start the computer and enter the BIOS settings, find the USB function option, and select "Enable";

3) The flash disk driver has not been installed (under WIN98 system).

Solution: Click "My Computer", select Properties, find "Universal Serial Bus", and delete it. USB MASS STORAGE item, click "Refresh", and then follow the prompts to reinstall the driver.

A blue screen error occurred during the process of copying files to a USB flash drive, causing the Windows program to be interrupted?

The reason may be: the U disk was accidentally unplugged, or there were other incorrect operations or looseness.

The solution: restart the computer, and then check the contents of the U disk to see if there is any loss or error. If so, reformat it again.

The file has been copied to the USB flash drive (you can see the copied content and open the file after double-clicking "Removable Disk"), but when transferring it to another computer, it is found that the file cannot be There is no content in the removable disk

Since the operating system will open a memory cache area when operating an external disk, many access operations are actually completed through this cache area, so sometimes when copying files to After "Removable Disk", although you can see on the display that the copied file has been copied to the removable disk and you can perform any operation, the file is not actually COPYed to the disk. Therefore, after COPYing the file, You should unplug it and plug it into the computer again to check whether the files are actually copied to the flash drive.

Why does an error occur when opening the file on another computer after copying the data to the USB flash drive?

It is caused by incorrect operations after saving the file.

Misoperation of the USB flash drive will cause the loss of stored files, interruption of the operating system, and even damage to the USB flash drive. Misoperations include:

1) Perform operations when the work indicator light is on for normal access. Plug and unplug the USB flash drive;

2) Plug and unplug the USB flash drive quickly and repeatedly. Since the host requires a certain response time, performing the next operation before the host has responded will cause system crashes and other problems;

3) When an error was discovered (perhaps before the reaction occurred), the USB flash drive was formatted quickly;

4) The USB flash drive was unplugged before the formatting was completed;

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5) The host USB interface is too loose, sometimes it can be accessed, sometimes it cannot be accessed;

6) The host operating system has a virus, causing the system to be unstable and unable to respond normally;

When checking the capacity of a USB flash drive in the resource manager, some USB flash drives display a slightly smaller capacity than the nominal value.

It is normal. There are many reasons:

1) The preset application software occupies a certain amount of USB disk space

2) There is a certain error between the actual display capacity of the USB flash drive and the scale of the USB flash drive. The nominal value indicates the specifications of FLASH used in the USB flash drive. The size of the error is related to the technical solution used. The error varies with USB flash drives of different models and capacities.

3) The USB flash drive uses Flash Flash memory technology is different from the magnetic storage technology of floppy disks and hard disks. Flash chip directly affects the capacity and quality of USB devices. There is a certain error between the chip capacity and the nominal value shown when the chip manufacturer leaves the factory, which will also cause the USB flash drive capacity to be different.

4) This is due to the difference in capacity calculation formulas between operating system identification and hardware device manufacturers. For the convenience of calculation, manufacturers often set 1KB=1000Bytes, 1MB=1000KB, and 1GB=1000MB. The operating system is 1KB=1024Bytes, 1MB=1024KB, 1GB=1024MB. This results in a discrepancy between the standard capacity of storage devices and the actual capacity used. It can also be deduced that the actual capacity of a 128MB USB flash drive should theoretically be 125MB, the capacity of a 64MB USB flash drive should be 62.5MB, and so on.

5) When the flash memory chip is manufactured, the flash memory medium is allowed to have bad blocks (Bad Blocks). These bad blocks cannot be used and are not counted as effective capacity.

6) Like the hard disk, the USB flash drive also uses the FAT file system, and the FAT file system includes the MBR main boot partition, FAT file allocation table and ROOT directory area, etc. These areas also occupy flash memory space and generally require Takes up several hundred KB.

After the USB flash drive is used for a period of time and is formatted again, its capacity will automatically become smaller.

When data is written, there needs to be at least one physical block (Block) inside the flash memory chip. ) is used as a swap block. This is because the write operation of flash memory is very special. It must be erased first and then data can be written. The smallest unit of erasure is a physical block, but the smallest unit of written data is a page (Page).

In the storage unit of flash memory, a physical block contains several physical pages. Therefore, when writing data, there needs to be an empty and usable swap block to store data that does not need to be erased. Due to the charging and discharging characteristics of flash memory, its number of reads and writes is physically limited.

Usually manufacturers will count the number of reads and writes inside the flash drive. When a certain physical storage block of the flash memory chip reaches the highest number of reads and writes specified, the block will be set to inactive. Reused area, so under extremely frequent use, the capacity of the flash drive may become smaller and smaller.

There are two types of flash memory products on the market: 1. Those without reserved buffer space; 2. Those with reserved buffer space.

In the first case, since there is no reserved space, the loss of swap blocks in the flash memory during reading and writing is quite large, so the capacity will become smaller and smaller.

For the second case, the manufacturer has reserved some physical blocks during design. For example, 1000 of the 1024 physical blocks are selected for data storage, and the remaining 24 physical blocks (including bad blocks) are used for data storage. Make buffer exchange block part. After each power-on, the logical address and physical address of the storage unit need to be compared again. The swap block is not a fixed block, so the probability of reading and writing operations on each physical block is almost the same, and no physical block will appear. The phenomenon of premature damage. For flash disks with reserved buffer space, the capacity will basically not become smaller and smaller.

However, most current USB flash drive products can already guarantee a service life of more than one million times of erasing and writing.

Encrypt the USB drive and install the driver on a WINDOWS XP computer. When the installation is about to be completed, it prompts "It has not been tested by the WINDOWS logo and its compatibility with WINDOWS XP cannot be verified."

Microsoft has added a digital signature testing function for drivers in WINDOWS XP to provide security measures to ensure that the drivers of user devices will not be tampered with and reduce the risk of users installing unprotected drivers.

When the above prompt message appears, you can select "Continue Installation" to complete the driver installation. If you do not require WINDOWS to prompt similar information in the future, you can do so through the following steps: Right-click "My Computer" on the desktop => Properties => Hardware => Driver Signature => Single-select "Ignore" and select "Replace this The operation is applied as the system default value"

The computer USB interface can be used normally when connected to other USB devices (such as scanners, printers, digital cameras). When connected to a USB flash drive, the flash drive indicator light does not light up and cannot be used< /p>

1. Check whether the connection between the USB flash drive and the computer is normal, and use another USB interface to test

2. Check the device manager to see if the "Universal Bus Device Controller" entry appears. If not, please activate (ENABLE) the USB interface entry * in the computer motherboard BIOS

3. If the computer has installed other types of USB devices, uninstall the device driver and install the USB driver first

4. Try this USB flash drive on another computer to confirm whether the USB flash drive is defective

Copy the files to the root directory of the USB flash drive. When the number of files reaches about 200, which is far from the nominal capacity of the USB flash drive, sometimes It prompts "The disk capacity is full" and the file cannot be saved

The USB flash drive uses the FAT file system, and the root directory storage area is fixed. According to the FAT file system standard, the root directory is in the msdos8.3 format. In theory, Can store up to 510 files (including the number of directories). In operating systems above Windows 95, if the files (including directories) stored are in 8.3 format, theoretically up to 254 files (including directories) can be stored. If it is not the 8.3 format, the amount that can be stored changes, and at least 25 can be stored. This problem can be solved by creating multiple classified subdirectories in the root directory of the USB flash drive and saving files in the subdirectories.

Why the bootable USB flash drive cannot be started on my computer

Maybe the motherboard model does not support it

How to judge whether a motherboard supports flash disk booting< /p>

The bootable USB flash drive starts the computer by simulating a USB floppy drive and USB hard disk. As long as the computer motherboard supports USB device booting, that is, the BIOS boot options include USB-FDD, USB-HDD or other similar options, you can use the bootable USB drive to boot the computer.

The first time I used a USB flash drive on a computer, the window prompting that new hardware was found did not appear, and the driver could not be installed.

The reasons may be:

1. Motherboard The usb controller is not enabled,

Solution: Enable this function in the computer motherboard BIOS

2. The usb controller is enabled but not running properly,

Solution : Delete the relevant devices under "Universal Serial Controller" in the device manager and refresh.

3. The USB flash drive is abnormally recognized by the computer and appears yellow in the device manager? or! "Other device" or "Unknown device",

Solution: Delete this device and refresh

A large-capacity U disk (such as a U disk with MP3 player or recording function (disk) or mobile hard disk cannot be used normally on the computer. Although the system prompts that an unknown USB device has been found, the U disk or mobile hard disk cannot be correctly recognized.

The reasons may be:

1 ． Insufficient power supply of the USB interface: The system assigns a maximum output current of 500mA to each USB interface. A general USB flash drive only requires 100mA of operating current, so there will be no problems during use. Most mobile hard drives use ordinary 2.5-inch hard drives, and their operating current is between 500mA and 1000mA. If the power is only supplied through the USB interface, it can still be used reluctantly when there are no other USB devices in the system. , but if the voltage is unstable, insufficient power supply may occur at any time. Especially when using a mobile hard drive that supports USB 2.0, the situation is most serious. In addition, if your laptop is powered by a battery, the USB interface allocates less power.

2. An external USB expansion card is used: When using a USB 2.0 U disk or mobile hard disk in a laptop, if the laptop does not support USB 2.0 technology, it generally must be indirectly supported by converting a PCMCIA card to a USB 2.0 expansion card. These extensions The cards basically use NEC's D720100AGM USB control chip, which provides at least two USB 2.0 interfaces and as many as five USB 2.0 interfaces, which is enough for ordinary users. Since the power provided by the PCMICA interface is smaller than that of the onboard USB interface, insufficient power supply may cause problems in the operation of the mobile hard disk.

Solution:

1) It leads an adapter cable from the end of the USB cable connected to the mobile hard disk, which can be plugged into the PS/2 interface on the back of the computer to draw power. Here you can Provides greater current output than USB interface.

2) Using the power compensation cable (also known as "keyboard cable"), if the optional power adapter is provided in the packaging box of the USB flash drive or mobile hard disk, you can directly use the external power supply, so You can fundamentally avoid the situation of insufficient power supply