What is a usb flash drive made of. What is a flash drive? Description and photo

How does a flash drive work?

Flash drives, or USB flash drives, are devices for storing, writing and reading information. Thanks to them, we can carry huge amounts of data in our pocket: photo albums, music concerts, price lists, maps, presentations, etc. But how does this become possible? Let's talk in this article about how a flash drive works.

How a flash drive works: device

The simplest flash drive is designed for at least 10,000 rewrite cycles. But the best specimens can withstand 100,000 cycles. If you do not overwrite information several times a day, this resource could be enough for an unlimited time. However, data is usually stored for no more than 10 years. As a rule, during this time people have time to replace the drive with a more modern device several times.

And yet, sometimes it happens that a flash card suddenly fails: when connected, the computer “does not recognize” it, reporting that it is an “unknown device”. To understand, you need to at least in general terms represent its device.

Inside a small flash drive, several blocks are placed:

• microcontroller;
• microcircuit (chip) of flash memory;
• clock frequency source - quartz resonator;
• Light-emitting diode;
• write protection switch.

The main part is the memory matrix. It consists of many cells in which information is recorded. One cell is 1 bit of information. The computer uses binary logic: it operates exclusively with zeros and ones. There is voltage in the cell - one, no voltage - zero. In order to write down one character - a letter, a number, a space, etc. - you need 8 bits or 8 cells. 8 bits are called a byte. Each flash drive can store millions of bytes of information.

The main advantage of the memory matrix is ​​that data is not lost in the absence of supply voltage, i.e. she is energy independent.

The controller controls the operation of the memory cells, this is the drive control unit. The controller, when connected, drives the current through all cells, checks where 0 is written, and where 1. The signal from the computer is fed to it through the connector.

In accordance with this request signal, the control unit accesses exactly those cells that are specified in the request, and allows the data recorded in these cells to enter the computer. Or vice versa, the controller reads the data from the computer and sends them to the selected cells.

For the normal functioning of the flash drive, a clock frequency is required, which is generated by a quartz resonator. It is he who sets the speed of the flash drive.

What to do to make the flash drive work without failures

Never pull a flash drive out of a running computer. You need to disable it first. In these cases, the computer writes that the memory device can be removed. This means that a shutdown signal was received from the computer to the controller, and the corresponding service information was written to the control unit.

If you pull out the flash drive without disconnecting, the service information in the controller may go astray, and then it will no longer be able to connect to the reader. The same thing can happen with sudden voltage drops.

The controller is the most vulnerable part of the flash drive. A high-quality memory matrix and a crystal oscillator almost never fail. To destroy them, you need to either break the USB device or apply very high voltage. But the connector can be crippled if handled carelessly.

One of the most convenient tools for transferring information from one computer to another is a flash memory or, in computer jargon, a flash drive.

A flash drive is a small but capacious storage device that you can always carry with you and connect to any computer for file sharing.

It connects to a computer using a USB connector. Such a connector is in any modern computer (or laptop), and it is not difficult to find it. In stationary computers, such a connector is located either on the front or on the back of the system unit, and on a laptop, USB connectors are usually located somewhere on the side:

To write information to a USB flash drive, you just need to insert it (USB flash drive) into the USB connector, after removing the cap (if any). The USB connector allows you to make a "hot" connection, so you do not need to turn off the computer when you connect or remove a USB flash drive.

The flash drive should fit into the slot without much effort, so if it does not fit, then you just need to turn it on the other side (180 degrees):

After connecting the flash drive, an autorun dialog box will most likely appear on the monitor screen, in which we will be asked to choose a method for opening files stored on the flash drive (this window may differ from mine):

Autostart of external devices is sometimes convenient, but I would still recommend disabling it for security reasons.

The fact is that when autorun of external devices is enabled, there is a high probability of infecting the computer, because. if a malicious program or a virus suddenly appears on the flash drive, then the infection will occur immediately when the flash drive is connected (the virus will start automatically).

In addition, you should not think that the virus gets on the flash drive only when copying. Keep in mind that if you simply insert a USB flash drive into an infected computer (this is especially true if this computer is in a public place) and immediately remove it (without copying anything), then even in this case there is a high probability that the virus has already got on a flash drive. By inserting such a flash drive into your computer with the autorun of external devices turned on, you will most likely infect your computer as well.

You can disable autorun of external media in Windows 7 through Control Panel - Autorun(or Control Panel - All Control Panel Items - AutoPlay). In the window that opens, take off just one tick:

In Windows XP, autorun is disabled as follows: click Start - Run. Next in the window Run type manually gpedit.msc

In the window that appears, go to the section Computer Configuration - Administrative Templates - System - Disable AutoPlay:

Right click on the item Disable autoplay and choose the item Properties, and then just turn off autorun and press Ok.

When autorun is disabled, you can find the contents of the flash drive from the window Computer:

In this window, by default, the flash drive will be displayed as Removable drive. The bar to the right of the icon shows how much space on the flash drive is occupied by files and how much free space is left on it.

By clicking on the icon of this device, we will open a window that will display everything that is on the flash drive.

Copying, moving, deleting and other actions with files are performed in the same way as with any other files on the hard drive. You can read more about this.

And after the work with the files is finished, the flash drive can be removed, but DO IT RIGHT!

Incorrect removal of the flash drive can lead to its inoperability!

Remember that before removing the flash drive, its work must be stopped. To do this, click on the icon of the connected device, which is located in the tray (lower right corner):

When you hover over this icon, we will see the inscription Safely Remove Devices and Drives.

If you don't see this icon, it means it's hidden. You can find it by clicking on the white triangle in the tray, which opens a menu with hidden icons:

In this menu we find the icon we need:

After clicking on this icon, a menu will appear on the screen with a list of connected devices (if there are several connected). We need to find our device and just click on its name:

A message will appear on the screen stating that the device can be removed:

note that only after the appearance of such a message can the flash drive be removed from the USB socket. Otherwise maybe damage to the flash drive (although it can carry it! :))

Keep in mind that if a write operation was performed at the time the flash drive was disconnected from the computer, then errors will appear in the file system of the flash drive. In this case, it is recommended to perform full format flash drive.

Formatting a flash drive is not difficult, but the main thing before that is to copy important files from a flash drive to a hard drive (if possible), because. formatting will destroy all the files that are on the flash drive.

To start formatting the flash drive, in the window Computer right-click on the flash drive icon and select the item from the menu that appears Format:

Read the warning carefully and click Ok to start formatting:

After a few seconds, the formatting will be completed:

Now the file system is in perfect order and the flash drive is ready to work again!

Well, at the end of the lesson I will give a few more tips!

1. To make it easier to find your flash drive on another computer (among other drives in the window Computer), you can rename it. To do this, click on the icon Removable drive right mouse button, select item Rename and give the flash drive any name, for example "My flash drive".

Now, on any computer, the flash drive will be displayed the same way, and exactly the way we want it:

2. From time to time it is advisable to check the flash drive for errors.

To check the flash drive, right-click on its icon and select the item Properties. In the window that opens, on the tab Service press the button Perform a check having previously closed all open documents with which we worked (on a flash drive):

In the next window, put all the checkboxes and click launch.

3. If you often use a flash drive, but the USB connector on your computer is in an inconvenient place (for example, on the back of the system unit), then I recommend buying a special USB extension cable (two meters long):

Plug one end of the extension cable into the USB port of your computer (where you inserted the USB flash drive), and put the other end directly on your computer desk.

Thanks to this USB extension, you no longer need to climb under the table (where the system unit is usually located) to find the right connector somewhere behind the system unit. Now a flash drive or other external USB device (for example, a digital camera) can be connected to the computer without getting up from the table, just by stretching out your hand.

Recently, information carriers based on flash memory chips have gained wide popularity. In popularity in our time, they have no equal: memory cards in cameras, cell phones, players, USB flash key fobs, and more recently, SSD drives. Many devices are equipped with memory card slots, such as printers, stationary DVD players, car radios, and many other multimedia devices.

And such popularity is not accidental: in terms of practicality, “flash drives” also have no equal. A large, constantly growing volume, which is already calculated in gigabytes and tens of gigabytes, a fairly high speed, as well as the declared reliability and durability (we will dwell on this issue in more detail within the framework of this article).

First, consider the flash drive device.

Flash memory gets its name from the way it is written and erased.

A typical USB flash drive, as well as most types of memory cards and SSD drives, are arranged as follows:

• the board has microcontroller, which provides a flash drive interface, processes commands and performs memory operations;
• one or more memory chips;
• and their electronic "strapping" of passive elements.

Some memory cards do not have a built-in controller, and are essentially a memory chip packaged in a case.

Let's look at the main components of a flash drive in a little more detail.

flash drive memory chips

All modern flash drives are based on non-volatile NAND memory chips. The abbreviation NAND comes from the phrase NOT-AND (logical function AND-NOT), which underlies the organization of an elementary logical cell on which this memory is built. Elementary memory cells in these microcircuits are combined into pages, and pages into blocks.

With such an organization, access to a separate memory cell is impossible, you can only read the entire page, and erase and rewrite only the whole block. Of the features of such an organization, one can note high speed and high density of placement on a chip.

But there are also disadvantages.

For example, if the power of the device is suddenly turned off while making changes to a certain data block, there is a possibility of data loss in this block, since it could be read into the buffer, erased in the main memory matrix, and the changed block has not yet been written to the memory. This is a common cause of so-called “logical” drive corruption.

It is known that operating systems of the Windows family have a “write-back” mode. This is when data is written to the drive directly without delay, and the file allocation table is stored in RAM, and is updated on the media after a while or when certain events occur.

As a result, quite often there is a situation when, having written data to a USB flash drive, the user immediately removes it from the connector without using the safe shutdown function, which just updates the file allocation tables on the media and “correctly” unmounts it from the system.

As a result, in the best case, the data will be physically present on the drive, but will not be displayed in the file tree, and in the worst case, the logical structure of the drive will be damaged, and the drive may no longer be correctly “detected”. As they say in such cases, "the computer does not see the USB flash drive."

In all such cases, data can be quickly restored by contacting our information recovery center.

The main problem with flash memory is the wear of memory cells.

The fact is that any flash memory has a limited number of rewriting cycles for each cell (from 100,000 to 1,000,000 cycles).

If in a camera or player where the data is not updated too often, such a limitation is not critical, then, for example, when working with databases on a flash drive, this resource can be used up quite quickly, since changes occur very often, as a result of which one and the same blocks of data.

In this regard, it is not recommended to use flash memory for work, constant access to data, as well as for installing an operating system on it, since the resource of such a flash drive will be exhausted very quickly, and the flash drive will become unusable.

Never use a USB flash drive to work in accounting programs!

Flash drive controller

The most complex and mysterious part of a flash drive is, of course, its controller.

Its main functions are working with memory chips (performing paging operations, data fetching, block writing, placing and addressing data in several memory chips, as well as other special functions) and providing an interface to the host device.

When a command is received to read a certain data cell, the controller must determine in which chip this cell is located, in which block of this chip, in which page of the block, and then the actual address of the cell in the page. Since only the entire page can be read, the controller reads it into its buffer, finds the desired cell in it, and sends its contents to the host device.

When a write command is received, the required block is also found, but this time it is not read page by page, but in its entirety. Then the necessary changes are made in the buffer, the block from the microcircuit is completely erased, and the changed block is written again from the controller buffer.

In addition, to equalize the wear of the blocks, the controller periodically reassigns them (in fact, swaps them). As a result, fairly even wear is achieved over write cycles, and the memory chips thus last longer. The controller monitors the status of each block separately, and if any of the blocks has exceeded the allowable number of rewrite cycles, the controller switches to read-only mode - data can be read from it, but it can no longer be written. Such drives are not suitable for further use.

In this case, you should copy the data from the media and replace it.

The controller has a firmware, configuration tables, and some models store tables of wear of memory blocks, as well as a lot of other service information. The variety of controllers is very large, and their versions are simply countless. Concerning, in case of any damage to the controller, it is pointless to look for a replacement to restore information.

To recover in this case, memory chips are soldered, read on special equipment, and the data is collected manually as a mosaic.

Electronic binding is needed to power the microcircuits and match the logic levels. And although there is nothing complicated here, it is not uncommon for this particular electronic harness to fail, especially the power stabilizer. Data recovery in this case depends on the degree of damage: either the electronics are restored directly on the flash drive, and the data is read out in the normal mode, or, as in the case of a burned-out controller, the data is taken directly from the memory chips and collected manually.

Recently, there are flash drives in which the controller, memory and all electronics are packed into one chip. These are monolith flash drives. This design is much more compact than the classical one, but it has many disadvantages: less reliability, weaker cooling, and the inability to access the memory chip bypassing the controller.

In the event of a controller failure, or an electronic harness in a similar flash drive, the complexity of data recovery work increases by an order of magnitude.

A question that often arises among potential buyers is which flash drive to choose, and how to choose a flash drive?

Many are guided by famous brands, in the hope that the products of a well-known company will be better and more reliable, but here things are a little different. As a rule, the trademark under which a particular flash drive is produced has nothing to do with the production of the device at all, but only orders a batch of ready-made flash drives with their own logos and packaging, and the product quality does not depend on the trademark in any way.

As a rule, it is impossible to select a flash drive by a specific controller or memory chips - even in flash drives of the same appearance from different batches, different microcircuits can be used.

Therefore, the criteria for choosing a flash drive is extremely subjective.- solid construction, rigid fastening of the USB connector, no moving parts, preferably a metal case (for better cooling and protection from static) and a classic multi-chip architecture.

The easiest way to distinguish a flash drive of a classic design from a single-chip one is by the USB connector - ordinary flash drives have a metal connector, like on any USB cable, single-chip connectors are usually thin, half the size of a port, without a metal part around the perimeter.

As you can see, despite all the pluses, flash drives have enough disadvantages, in the light of which it is not worth trusting flash drives with valuable information in a single copy.

At present, a portable storage device will not surprise any user with its functionality. However, at one time, the flash drive made a truly technological revolution in the field of data storage devices. This device replaced floppy CDs, as well as floppy disks, gradually ousting them from the market.

In this material, we will consider the device of a flash drive, the principle of operation and connecting it to a personal computer or to another device capable of reading information from a portable drive. Let's figure out how to restore a non-working flash drive, as well as remove write protection.

General information about the portable flash device

The USB flash drive was invented by Israeli scientists working for M-Systems in 1999. But the device itself was patented in the United States of America, also in 1999. The first presentation of the flash drive took place in 2000, where it received its original name DiskOnKey (disk on a key). The volume of the first portable drive was 8 megabytes, but devices of 16 and 32 mb soon appeared.

At that time, a flash drive could be called a full-fledged gadget, it was sold for a considerable price of $ 50, which increased by the end of the year with the advent of larger drives up to $ 100 per piece. The sale was led by IBM.

Currently, flash drives have almost completely replaced obsolete CDs from the portable device market. Now there are two terabyte drives from manufacturers such as HyperX and Kingston. Just imagine the size of one and a half matchboxes, on which there are two terabytes of disk space. How does a two terabyte flash drive work? Just like a flash drive with 16 gigabytes, everything is very simple and very effective.

Advantages and disadvantages of a USB flash drive

Since today these devices are indispensable portable storage media, you should understand what their advantages and potential disadvantages are. After all, it is these two parameters that accompany the progress in various technologies and the development of the latest devices. Indispensability means monopoly in any device market. So, let's find out how and in the process we will indirectly get acquainted with how a flash drive works.

Advantages:

1. Portability and light weight of the device.
2. Quiet operation and low resource consumption.
3. Low power consumption (primarily due to the absence of mechanical systems).
4. Possibility of operation at high temperatures.
5. Resistant to mechanical stress (unlike hard and compact drives).
6. Protected from environmental influences (scratches, dust, destruction from drying out).
7. Long-term data storage offline at best from 10 years and above, at worst with a low-quality device from 3 to 6 months.

Flaws:

1. Limited number of writes and erases of data before failure. About 5000 rewriting cycles.
2. The limited number of USB connector connections is about 1500 times.
3. Limited write speed, which is quite noticeable for a USB 2.0 port (no more than 35 megabytes per second).
4. Sensitive to electrical shorts and radiation, like any other electronics.
5. A disadvantage in the shape of the connector and the connected drive, which increases the wear on the port and connector. This issue has been resolved with the USB Type-C output.

Thus, from the bulleted list above, you were able to learn about the advantages and disadvantages of a flash drive. Based on this information, we can conclude that this device, in fact, has few shortcomings, which, if desired, can be corrected and finalized.

How a USB flash drive works

The principle of operation of a flash drive is based on connecting it to the USB port of a personal computer and subsequent operation to download and delete data from it. A USB device is based on the following types of flash memory: NAND or NOR. Flash memory in its composition contains silicon crystals, on the basis of which field-effect transistors with insulated or floating gates are placed. The latter, in turn, can hold a charge, in other words, electrons. It should be noted that field-effect transistors have a drain and a source.

While writing to a USB flash drive, a positive voltage is applied to the control gate by the controller, thereby some part of the charge moves from the drain to the source with a deviation to the floating gate. Some of the electrons, after being deflected, overcome the small insulator layer and then penetrate the floating gate, where, in turn, they remain for a long time (storage). Storage times are listed above in the pros and cons section, however, these data will vary for different manufacturers and sizes of flash device memory.

Flash drive device

The USB storage device is shown in the image. It is worth saying that when a user connects a USB flash drive and then uses it for his own purposes, at that moment very complex processes controlled by the memory controller take place directly in the portable media itself.

The above image contains all the main elements of the "flash drive", but not all. The image below shows the remaining elements of the device.

1. USB connector for receiving and transmitting data.
2. Board checkpoints.
3. Quartz resonator.
4. LED for signaling device operation.
5. Write-protect switch.
6. Place to connect the memory controller.

This is what a portable portable device is disassembled and decomposed into individual circuit components. From the above information, it becomes clearer how a flash drive works. What if it's wrong?

The flash drive does not work: how to restore and what to do

This guide will be brief because if your removable device fails due to physical malfunctions or due to wear and tear of functionality, it will be more expensive to restore it than to buy a new one. You know how a flash drive works, you also know from the information presented above what it consists of. Unfortunately, you will not be able to manually repair it without proper skills, so in extreme cases, take the device to a service center.

In order to check the performance of a flash drive, it is enough to connect it one by one to different ports on your computer or reader. If none of the ports recognizes the flash drive, try connecting it to another computer or device that can read information from the media. If the device is working, then it will definitely open. Also, to recognize the device on your computer, you can try updating the USB port driver.

The flash drive is write protected: how to remove protection

You can remove write protection from a flash drive in several simple ways. The first way is physical protection installed on the drive case. You can remove it by moving the key to another position (for recording). The second way will be one of the most common solutions to the problem, this is formatting the device to a different file system (NTFS and FAT32). An alternative method is to solve the problem through the command line. To do this, start the DiskPart system service through the Run console interpreter, then write the command "attributes disk clear readonly", without quotes.

How to connect a flash drive to a computer

The correct connection of a removable drive to a computer is to connect the USB flash drive connector to a USB port that matches the speed of the device's connector model and data transfer rate. Accordingly, this is a 2.0 or 3.0 port, and it can also be a connection method through the latest Type C port, which is currently widely used by Apple on its MacBooks. In some cases, it happens that due to the incompatibility of the port and the flash drive, the computer does not recognize it. Therefore, connect correctly.

Conclusion

From the above information in this article, you learned about the origins of removable storage, its advantages and disadvantages, as well as the complete structure and principle of operation of a removable flash drive. The article discussed how a flash drive works and how to properly connect it to a reader. We were also able to get acquainted with how to remove write protection.

You can read about what a flash drive is on many sites. You will also be told in detail what not to do with it. But how do you know what to do with it? How about a lesson with a visual demonstration on all points (from A to Z) about working with a flash drive? Let's say that you want to transfer text from one computer to another (let the second computer be not connected to the Internet).

And in the second case, a cartoon, in the third case, both. What is most important in the lesson is ALL sequential transfer actions. Original requirement? But after all, this is the only way to show, explain, save a dunno (a pebble in the garden of beginners, not to cope with a flash drive) from unnecessary and unnecessary actions!

There is a lot of information about the flash drive, but there is no specific step-by-step “instruction” for working with the flash drive! But in vain! I am sure that many people have such “difficulties”, but write about them. So keep the lesson about working with a flash drive.

This is what a regular flash drive looks like.

Step 1. Insert it intoUSB port(see picture).

Next to this port are usually the headphone and microphone jacks.

Here they are next to green and pink.

Step 2 Now press "Start". Then "My Computer". Among the pictures you will see a picture of a removable disk. She can have any name.

The main thing is its visual image in the picture. For example, "KINGSTON (F:)". In this case, "KINGSTON" means the name of the manufacturer of the flash drive, and (F:) is the name of the disk.

Step 3. Write information to a flash drive possible in at least 2 ways. Let's consider both.

1 way. Let's continue where we left off.

1. Click on the image of the flash drive with the left mouse button. As a result, you will see its contents.

2. Select on the desktop or in any other folder the desired file (text document, music, video, whatever) that you want to copy to the flash drive.

3. Now grab it with the left mouse button and drag it to the flash drive folder. Let go.

Everything. You have copied the file to the flash drive!

2. way.

1.Select the file you need to copy to a USB flash drive.

2. Click on it with the right mouse button.

3. Select "Submit"

4. Then select the item with the image of the flash drive. In our example, "KINGSTON (F:)".

5. That's it, the file has been sent to the USB flash drive. You can check its availability on the flash drive.

Step 4 The information you wrote down . Now you need to safely remove the flash drive from the computer. To do this, do the following.

That's all. Now you have mastered the work with a flash drive. And we are ready to conquer new computer horizons! Good luck with this!