How does a flash drive work?

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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 pockets: photo albums, music concerts, price lists, maps, presentations, etc. But how is this possible? Let's talk in this article about how a flash drive works.

How does the flash drive: device

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

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

Inside a small flash drive is placed a few blocks:

  • microcontroller;
  • microcircuit (chip) flash memory;
  • clock 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 - 1 bit of information. The computer uses binary logic: it operates exclusively on zeroes and ones. There is a voltage in the cell - one, no voltage - zero. To write 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 the data is not lost in the absence of a supply voltage, i.e. it is non-volatile.

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

In accordance with this request-signal, the control unit addresses precisely those cells that are indicated in the request, and allows the data recorded in these cells to go to the computer.Or vice versa, the controller reads data from the computer and sends it to the selected cells.

For the normal functioning of the flash drive requires a clock frequency that 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 smoothly

Never remove a USB flash drive from a running computer. You must first disable it. 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 recorded in the control unit.

If you pull out the flash drive without shutting down, in the controller, the service information may get lost, and then it will not be able to connect to the reader. The same can happen with sudden voltage drops.

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

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