What is a flash drive. What is a flash drive

At present, it is already difficult to surprise someone with a flash drive. These miniature products have become so firmly established in our daily lives that it is now very difficult to do without them. This is especially true for students who simply need such devices for passing term papers, essays and other purposes. What is a flash drive? Only the lazy can not answer this question.

The modern market is literally flooded with a variety of models. Many companies can offer original designs as well as smaller versions of flash drives. And so much so that you involuntarily wonder if this is really a flash drive or something else?

What is a flash drive?

Many people know that with the help of a small device, you can transfer a variety of text electronic documents, music and video files from one computer to another. But not everyone clearly understands what it is.

A flash drive is a removable device for transferring or storing information. What is characteristic, there are no moving parts inside the USB flash drive, which provides it with a high level of reliability. To record data for further distribution or storage, a file system is used (usually FAT32 or NTFS).

In this case, it is more correct to pronounce not a flash drive, but a USB flash drive. What are her (or his) virtues? More on this below.

Obvious benefits

• Easy operation. It is much easier to transfer any information to a USB flash drive than to a CD. To record it, one cannot do without the help of specialized software. In addition, you do not need a floppy drive to open the flash drive.
• Unlike the floppy disks discussed above, as well as disks, USB flash drives are more reliable.
• Reusable use. It doesn't matter how many GB a flash drive has, there can be several thousand rewrite cycles, which is not so bad.
• Price. It is worth noting that the prices for flash drives are only decreasing every year due to updating models and increasing volume. And now the simplest USB flash drive costs less than $5.
• Compact size: USB sticks are manufactured in a small size and light weight.
• Appearance. Many manufacturers are trying to surprise users by giving USB drives an original design.

Among other things, modern flash drives are a pleasure to work with, as they are characterized by high write speeds, unlike optical discs - up to 20 megabytes per second, or even more.

Due to this, the entire process of copying to a USB drive takes several minutes, depending on the amount of information.

Some disadvantages

Parsing the question of what a flash drive is, do not bypass the existing shortcomings. For some, some of them may seem insignificant. But among all the significant disadvantage is the service life. The number of entries and deletions is not infinite. But in the end, it may well be enough for a period of 5 to 10 years. In this case, the recording speed will gradually decrease.

A flash drive cannot work wet. Although this drawback is no longer significant, since it means connecting it after taking a shower. But if you let it dry well before that, the device will be able to work properly.

Usually USB drives are sold with a protective cap, which is often lost. Of course, this cannot be attributed to serious shortcomings, and it's all about inattention on the part of users. Nevertheless, the sediment remains, because you can come up with some kind of chain. Although miniature models are also easy to lose, and this is already serious, especially if they are not cheap. It's not up to parsing what a flash drive is.

Wide range of

The modern market can offer a great variety of flash drives from a variety of manufacturers. In this case, the case of information carriers can be made of different materials:

• plastic;
• rubber;
• metal.

Metal drives are more expensive, but at the same time, unlike plastic counterparts, they are highly reliable. To damage the body, you need to try hard.

Rubber flash drives may appeal to active users. Such devices are characterized by high shock-resistant and waterproof properties. Plastic drives can be a wonderful gift for any celebration - birthday, New Year and other pleasant occasions.

The use of flash drives

Any user who knows what a flash drive is will not be surprised by the fact that with the advent of CD, DVD and Blu-ray discs, floppy disks have lost their relevance, although not completely. But despite their decline, they have not yet completely gone out of use, and to this day several million copies are sold every year. According to most analysts, these media will be used for several more years. At least until the cost of flash drives and floppy disks is equal.

It does not threaten USB drives! And it's not that every computer or any other similar device has a corresponding connector. A flash drive can be used not only for transferring or storing various files, it can be easily used for other purposes. For example, it can be used to install an operating system. How to do this will be discussed.

What is bootable media?

What is a USB flash drive is known, but what is a bootable flash drive? There are times when you need to install an operating system, but there is no drive at all (this applies to many netbooks) or it does not work. Then a special bootable USB device will come in handy. This is a kind of "lifeline" for any user.

Bootable media can come in handy in cases where the system has crashed or the computer has stopped booting. It will allow the system to boot quietly in order to troubleshoot problems. After that, Windows will work properly, as before.

Ways to create a boot device

To decide how to make a USB flash drive bootable, you can use several methods:

• Powered by UltraISO software.
• Using the command line.
• Via the Windows 7 USB/DVD Download Tool.
• Through the Rufus utility.

All of these methods are easy to follow. It is only worth clarifying that if the bootable media is made using various utilities, then you will need an image of the operating system, preferably in ISO format. And in order for it to fit on a USB flash drive, its volume must be at least 4 GB.

The image should be prepared in advance using the same UltraISO program or any other appropriate type. Then let it be stored on the hard drive, which will save the optical media with the operating system, which is prone to scratches with frequent use.

After creating a bootable USB flash drive, it is imperative to set the initial boot from the USB device in the BIOS.

Using UltraISO

With the help of this program, you can create and edit various images, but in our case, several of its other features will come in handy. The first step is to download the software, preferably from the official website, and install it. You need to run the program with administrator rights, for which you can right-click on its shortcut and select the appropriate item.

The program has a Russian-language menu, which is very convenient. First of all, you need to connect the USB flash drive to the USB connector, and then you can run UltraISO. Then click on "File" and then "Open". Then you need to specify the path where the image of the operating system lies, select it, then click the "Open" button.

Next, you need to go to the "Boot" menu and select the "Burn hard disk image" item. A window will appear in which you need to check the settings. In the Disk Drive section, the desired device should be selected, where the recording method should be USB-HDD +. At the same time, check whether the image is selected to create a bootable USB flash drive.

Now it remains to click on the "Record" button, which will start formatting, and answer in the affirmative to the message that appears. This process deletes all data! At the end, a window will appear with a message about the success of the recording. That's all - the flash drive is ready.

Command line help

You can also prepare a USB flash drive for installing the operating system using the tools of Windows itself. What you need can be run in different ways:

• "Menu" - "Start" - "Programs" - "Accessories" - "Command Prompt".
• Press the key combination Win + R (or "Menu" - "Start" - "Run"), in the empty field of the window, enter cmd.

As a result, a black window will appear, which is what you want. In it you need to type the text diskpart and press Enter. This key is pressed after each command entered. Now, in fact, instructions for creating a bootable USB flash drive:

1. Enter list disk - a numbered list of all connected disks to the computer will be displayed.
2. Enter select disk X - instead of X, you need to substitute the number that corresponds to the flash drive (2 or 3, or 4, and so on).
3. The clean command is entered - the media will be cleaned.
4. Now we need another command - create partition primary - a partition is created.
5. Enter select partition 1 - the created partition will be selected.
6. The following text active activates the selected section.
7. After that, you will need to enter format fs = NTFS - the formatting process will start in the NTFS system. It takes some time, so you have to be patient.
8. You can now exit DiskPart mode by entering the Exit command.

The main part is done, after that you need to copy the Windows files to a USB flash drive, and in the same form as it was on the installation disk.

Windows 7 USB/DVD Download Tool

This utility was created by Microsoft, which is responsible for the release of operating systems of the Windows family. To create bootable media, it fits perfectly. To get started, you need to download the program from the Microsoft website and install it on your computer.

You also need to run the program with administrator rights (how to do this was described above). After do the following:

• Click Browse, select the desired operating system image and click Next.
• Now you need to select the USB device.
• At this step, you will need to select your USB flash drive from the entire list of devices (usually it should already be selected). Then click Begin copying.

The formatting process will start, after which the necessary files will begin to be copied to the flash drive.

Mobile help represented by Rufus

To install different versions of Windows from a flash drive, the Rufus utility may come in handy. This program does not need to be installed on your computer, it starts working immediately after downloading. Setting up a bootable USB drive with it is not difficult, for which you need to follow these steps:

• Connect the flash drive to the computer, and in the "Device" utility field, it should be selected.
• Pay attention to whether the checkbox "Create a bootable disk" is checked below.
• You can, if necessary, uncheck the "Quick Format" item, only in this case the process will take some time.
• Click on the floppy disk icon and select the prepared operating system image.
• Press the "Start" button.

Formatting will start, but before that the program will notify that all data will be destroyed. Click OK and wait for the creation of bootable media to complete.

The listed methods on how to install an operating system from a USB flash drive are easy to implement. However, the USB stick needs to be used properly. Then Windows can be installed, and other files will be safe.

Proper use of flash drives

It is not enough to choose a flash drive, you need to use it correctly. To do this, you should follow the elementary rules:

• It is not recommended to pull out the connected flash drive immediately after copying the files. You need to use safe extraction. Otherwise, damage to the file system cannot be avoided, which will only help fix the formatting, and this is already a guaranteed deletion of information.
• An infected flash drive must always be treated.
• As experts advise, it is better to change the drive every 2-3 years, since the cost allows this.
• Try to avoid impacts and prevent flash drives from falling, as well as immersing them in water.

If it is impossible to carefully connect a USB flash drive to a computer for various reasons, you should take a closer look at devices in a secure case.

When choosing, do not take into account active advertising, since any quality product does not need it!

In conclusion

So that the choice of a flash drive does not turn into a headache, you need to correctly approach the choice of device. You should not be guided only by the big name of some popular brand. Without a doubt, many firms can offer quality products. But only those manufacturers who have passed the test of time deserve trust. In this case, you can be sure that the purchased drive will last a long time.

It is also worth considering that you can infect your computer through a USB flash drive. And to avoid this, you must use licensed anti-virus software!

How to recover deleted files from flash drive? What is the difference between flash drives and external hard drives? How to recover data?

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What should I do if I accidentally deleted files from a flash drive? Stop! Whatever you do next, in no case do not write anything to this USB flash drive. After that, you should evaluate how important your data is so that you can try to recover the data yourself. If you decide that the data is very valuable to risk it, then it is better to take the flash drive to a professional data recovery company. Do you have any questions? Leave your phone and the manager will call you back

information

An information carrier using flash memory (eng. Flash - “fast, instantaneous”) is a microcircuit with electronic non-volatile memory capable of storing recorded information for an unlimited time and maintaining its state until an electrical signal of a different polarity is applied to the outputs. These are high-quality universal rewritable storage media, focused on consumer electronics products and next-generation computer equipment.

Flash memory is available in the following types: CompactFlash, SmartMedia, Memory Stick, Floppy Disks, MultiMedia Cards, etc.

MultiMedia cards, for example, weigh less than two grams, are the size of a postage stamp, and have memory capacities ranging from 8 to 64 MB. Such cards can replace not only floppy disks, but magneto-optical, small hard disks and rewritable CDs. Modern flash cards have a capacity that is a multiple of two to the power: 26 = 64, 27 = 128, 256 = 28 MB, and so on. It is assumed that the maximum capacity of such cards will reach units of GB. Such plug-in cards are used in digital voice recorders, portable players, camcorders, car radios, personal digital assistants (PDAs), cell phones and multimedia projectors.

Information carriers distinguish by physical structure(magnetic, semiconductor, dielectric, etc.), material type(paper, plastic, metal, combined), data presentation form(printed, handwritten, magnetic, perforated), reading principle(mechanical, optical, magnetic, electrical), design(tape, disk, card).Information carriers can also be classified according to the type of messages stored on them, and the materials of information carriers are characterized by the purpose of their use.

By intended use data carrier materials can be classified as materials used for recording, presenting and storing textual, digital, graphic data, static and dynamic images, sound (magnetic and non-magnetic) or a combination thereof, for example, multimedia data. Both classifications are closely interconnected; moreover, it is impossible to unambiguously classify carrier materials. The kinds of different messages are shown in Table 5-1.

Table 5-1

Types of different messages

Message type	Information carrier
Text	Document
Sound	Phonogram
Image (static)	Photograph, graphics, drawing, etc., transparencies (slide), hologram, static image or text information scanned with a PC
Image (dynamic)	Animation, video film, motion picture, TV
Combination of different types of information	Multimedia

as static carriers images used: paintings, etchings, drawings, etc. on canvas, cardboard, paper, film, etc.; video cassettes with magnetic tapes for VCRs and video players; magnetic vinyl diskettes; removable and non-removable hard and magneto-optical disks; compact plastic or glass laser discs ( CD, DVD ) used in computers; slides and transparencies, photographic materials, holographic plates, plates with memory for digital cameras such as flash memory, etc.

For the operation of audio-video equipment as sound carriers and/or dynamic images used: films and plastic gramophone records, magnetic audio and audiovisual tapes, films, vinyl diskettes, hard magnetic, magneto-optical disk drives, compact disks, memory plates for digital cameras and cameras, holographic plates, etc.).

multimedia data carriers magnetic audio and audiovisual tapes, floppy disks, drives on hard magnetic, magneto-optical disks, compact disks, memory plates are considered.

Various requirements for their operation and storage (climatic, sanitary and hygienic, fire-prevention, technical, technological, etc.) are imposed on information carriers.

Consider the basic materials of information carriers and their forms.

carriers images:

1. Paper . Historians claim that paper was invented in China about 2,000 years ago. However, much earlier (approximately since VIII century AD), the ancient Egyptians made scrolls from papyri, from where the word denoting the paper carrier "papyr" came from. Then the basis of paper carriers were rice straw, bamboo, rags, wood and other materials.

Synthetic (polyethylene) paper has been industrially used abroad since April 1967. The fibers of the material, called " Tyvek» ( Tyvek ) have a thickness (diameter) of 0.5–1 µm. It is a smooth and opaque material that incorporates the best properties of film, paper and fabric. It has a low specific gravity, high strength, resistance to punctures, tear and abrasion, vapor permeability, water repellency, rot resistance and biological inertness. Experts say that this material can replace traditional paper, especially in the manufacture of envelopes and any printing.

The material is resistant to most chemicals and is suitable for varnishing, laminating, heat sealing and bonding. It retains strength and flexibility up to a temperature of 73°C. It is believed that it is most suitable for outdoor advertising, covers of textbooks, geographical maps, guidebooks, etc., as it does not fray on the folds and does not deteriorate from water. However, to print on such material, you have to use special inks.

Similar material " Polylith» ( Polylith ) was imported to Russia in 1998. It is made from polypropylene resin mineral hardened with a mixture of neutral calcium and titanium dioxide to give a white and dull finish. It is the cheapest of synthetic materials, is resistant to water, heat, oil and chemicals. Another similar material is Robuskin» ( Robuskin ), an important distinguishing feature of which is the ability to print on it with conventional inks with virtually no readjustment of the printing equipment used for plain paper. There are, of course, other synthetic materials, including those with a self-adhesive backing.

The paper base is used in books, manuscripts, maps, diagrams and other similar documents. From the beginning of the appearance of manuscripts, books and until the middle XIX centuries, they were created mainly on paper from cotton and linen fibers. This is durable paper. From the end of the 19th and into the 20th centuries, paper was used mainly sulfite pulp and wood pulp. Modern books are mainly used as a carrier cellulosic materials.

2.Canvas, cardboard, hardboard and other art materials , on which pictures are written, engravings and etchings are printed, they are usually specially processed materials of woodworking (cardboard, hardboard) and weaving (canvas) industries. In addition, waste is used as a material for these purposes. wood(first) and linen or the like. (second). In this case, the canvas is coated with a special composition (primed) before applying paints to it.

3. photographic materials (negative, positive) are used for media such as photographic plate, photographic film, film or filmstrip, transparencies or slide, microfilm or microfiche. For these media, films are mainly used on cellulose, polyester base.

4. gramophone record usually made by pressing plastic mass(vinyl). Represents a round disk, on the surface of which concentric (spiral) grooves are applied, running from the outer side of the disk to its center. Discs differ in diameter, recording speed, number of audio channels and content.

To sizeThese disks are divided into three types:

1. "Giant" - 30 cm in diameter (playing time of one side 25-30 minutes).

2. "Grand" - with a diameter of 25 cm (the playing time of one side is 12-15 minutes).

3. "Mignon" - 17.5 cm in diameter (playing time of one side is 6-8 minutes).

By disk rotation speed gramophone records come in 4 types: 16, 33, 45, 78 rpm.

By record type records are divided into: monophonic, stereophonic and long-playing. Long-playing records have narrower grooves and a smaller distance between them (pitch) than conventional records, which allows for longer playing times. Stereo records contain a two-channel recording (left and right channel along the left and right walls of the groove).

5. Hologram - a plate with lithium niobate crystals or a photopolymer film. Holographic memory, unlike CD technology, represents the entire volume of the storage medium of the carrier, while data elements are accumulated and read in parallel. It allows you to place 1 TB (trillion bytes) in a crystal the size of a sugar cube, that is, information with a volume of more than 1000 CDs. Modern holographic storage devices are called HDSS (holographic data storage system).

6. Magnetic tapes in audio and video cassettes, streamers, magnetic disks in PC floppy disks are made of synthetic materials with a magnetic layer (usually iron oxide) on the lavsan or vinyl basis. Disks in HDD are made of light metal (aluminum) or glass and coated on both sides with a magnetic layer.

7. Magneto-optical disks (MO disks) are placed in a plastic case. Recording by a laser with a temperature of about 200°C on the magnetic layer occurs simultaneously with a change in the magnetic field. This property provides high reliability of storage of recorded information.

8. V optical (laser) disks - CDs for audio-video recordings and other machine-readable information. The carrier material in a CD is polycarbonate, polyvinyl chloride or special glass with a reflective (sprayed) aluminum layer. Use optical recording method. They can be classified as a medium, a carrier of various text, digital, sound and video recordings, multimedia, etc.

Distinguish: AudioCD CD-ROM, CD-R, CD-R W and others.

CD- ROM. The CD-ROM replication technology is similar to the production of gramophone records - printing (stamping) from matrices. In the process of writing, the laser acts on the photoresist, leaving lines-marks on it. The photoresistive layer is developed and metallized. Then, using the electroforming method, a second one is made from the original - completely metal, and intermediate copies are created from it by stamping. Many matrices are created from them, from which the manufactured products are replicated on CDs.

CD-Rused for a single laser recording or a single recording with the addition of several recordings to the same disc in the form of sessions (recording).

CD-RWallow you to repeatedly (hundreds and a thousand times) erase and write information to them.

Compact discs are distinguished by high recording density (about 300 thousand pages of text in A4 format), the ability to quickly search for information stored on them (a few milliseconds), and the durability of the media (tens of years).

This carrier has up to four recording layers and a capacity from units (4.7) to tens (17) GB. In this case, the duration of the recording increases to 8 hours. Increasing the information capacity of the disk is achieved through the use of a laser with a shorter wavelength of radiation (0.635-0.66 instead of 0.78 microns), as well as video data compression technology in standards MPEG , which made it possible to increase the density of data recording on these disks and the speed of reading information from them. For example, the digital video data rate is 1.3 Mbps, which provides high quality video (better than VHS ), and on the monitor is better than on the television receiver.

There are many varieties of compact discs that differ in the use of various media materials, recording methods, etc. Among the new devices, it should be noted “blu- rayDisc».

Blu-ray Disc Technology developed at the end of 2001. Since February 2002, its specification has been supported by a number of well-known foreign companies. Disks with a diameter of 12 mm have a capacity of 23.3; 25 and 27 GB, the thickness of the transparent protective layer is 0.1 mm, and the track width is 0.32 mm, which allowed not only to provide more capacity, but also to increase the read / write speed. The base speed of devices for working with these drives (1x) is 36 Mbps (5.5 MB/s). Recall that at DVD this parameter is 1.3 Mb / s, and for CD – 150 KB/s respectively. According to the developers, these discs are well suited for recording television and video programs broadcast in digital format.

9. Flash -memory - solid-state built-in and replaceable thin memory wafer made of semiconductor materials. Contains a flash memory chip with exposed contacts. These cards draw power from the devices they connect to. The amount of stored information is from 16 MB to 4 GB.

Information is recorded and stored on different media by different methods. Forms of storage and storage media are presented in table. 5-2.

Table 5-2

Forms of storage and storage media

Information form	Information carrier	Information recording method
Mechanical	plate	analog
Optical	paper	sign-symbolic
	film film	analog
	laser audio disc CD-A	analog
	laser disc CD - ROM , DVD	digital
Magnetic	audiovisual film	analog
	floppy disks	digital
	hard drives	digital

The possibilities of using various media and their materials for recording and using even one type of data are very diverse. So, text can be recorded on almost any media, presented as a static or dynamic image on the following media materials (Fig. 5-2).

Rice. 5-2. Materials of text information carriers

Sound, recorded on various media, is an important component of various funds and collections. Such media may be provided to users and used for official purposes; be stored for a short time or for a long time, etc.

Audio recordings and gramophone records, available in one copy, are not recommended to be issued to users at home. It is better for information services that serve users to purchase sound recordings in at least two copies in order to keep one of them in the reserve fund. If they contain records in one single copy, then it is advisable to rewrite them, for example, on a magnetic tape, floppy disk or disk to replenish the main fund of sound recordings provided to users, and store the first copy in the reserve fund.

The sound is recorded and stored on the storage media shown in Fig. 5-3.

Rice. 5-3. Audio media

If there are high-quality tape recorders or music centers in the information services serving users, the purchased one copy of the sound recording on magnetic tape is stored in the reserve fund, and copies are made from it on their own, which are issued to users.

Static video information obtained in the process of photographing and processing photographic materials (development and printing). Until the mid-1930s, many photographic materials were produced on a cellulose-nitrate basis (nitrate-based film was produced until 1951). In the late 1940s, silver-free powder photography appeared - xerography. In the 1950s, a way to create short-lived copies appeared - thermography.

The type of photography is micrography. Photographic recording allows documents to be stored in the form of microfilm and microfiche, i.e. microforms - microcarriers. Microcarriers are photographically reduced copies by tens and hundreds of times from various originals (manuscripts, drawings, drawings, printed texts, etc.).

Microforms serve as a protective copy of the original. The basis of micrographic film is plastic bases. It is the most important factor determining the durability and safety of the film. The insurance (archival) funds store reference negatives of the first generation (master negatives), which are used in the microfilming of manuscripts, archival materials and rare publications.

Vesicular, photothermoplastic and electrophotographic films are also used in micrography. They are mainly used for working microforms. Microcarriers are used in information centers, archives, libraries, research, design and other institutions.

Relatively cheap and widespread type of audio-video data carrier are magnetic tapes and disks. They are convenient to use. Reliable methods have been developed for the physical protection of magnetic media from damage, errors during reading, and spontaneous disappearance of data. Thus, it is recommended to carefully wind, clean and rewind magnetic tapes in both directions every six months, and copy every 12 months. The UK Government Computer Agency believes that magnetic tapes can be stored for up to three years under normal conditions, but recommends checking samples every 18 months.

A modern way of recording audiovisual data presented to users is to "digitize" them, followed by recording them on CDs. Work on creating a method for digital recording and playback of sound has been intensively carried out since the early 70s of the twentieth century. At the end of 1982, the first CDs appeared on sale.

The life of CDs will be significantly reduced by excessive heat, humidity, or direct sunlight. Therefore, it is recommended to store discs in a cool, dark and dry place.

In today's computer world, it's hard to find people who haven't heard of flash drives. However, many still do not have a complete understanding of these devices. In this article, we will fill this gap and talk about the main parameters and characteristics of USB drives.

Introduction

At the present time, it is difficult to find people who would not have heard of such electronic devices as flash drives or simply “flash drives”. Technical characteristics and optimal shape allowed them to take a leading position among portable storage media, and practically replace optical discs and floppy disks.

However, despite the popularity of flash drives, not all users have a complete understanding of these devices. In this article, we will try to fill in these gaps so that you can choose the right flash drive for yourself in any computer store.

As in the case of other storage media, flash drives have a number of basic technical characteristics by which they are selected. Let's look at the main ones and see what you should pay attention to when buying a flash drive.

What is a flash drive

A flash drive is a USB storage device that uses non-volatile flash memory to store information. The main advantages of flash memory include its low cost, compactness, noiselessness, mechanical strength, speed and low power consumption. Thanks to all these advantages and ease of use, flash drives managed to gain popularity among users in a fairly short time and oust other competing solutions from the market.

The main purpose of compact USB drives is to store, exchange and transfer data of not too large a volume. In addition, flash drives can be used to store backups and boot operating systems. At the same time, flash drives can be connected not only to a computer, but also to various household appliances, such as TVs, players, players and others that have USB connectors.

Despite all its advantages, flash memory still has a number of certain disadvantages. First of all, this is a limited number of write / rewrite cycles of information (up to 10 thousand times for MLC memory, which is installed in most devices, and up to 100 thousand times for SLC memory). Flash drives also have a limited shelf life. And although most manufacturers claim that their products can store data for 10-20 years, in fact, the company's warranty for this kind of media is no more than 5 years.

Like any low-voltage electronics, flash memory is very sensitive to electrostatic discharges, which are quite common in everyday life. Another reason for the fragility of the flash drive can be the USB connector, which, due to the frequent connection / disconnection of the media, can simply break.

True, all these shortcomings do not prevent flash drives from remaining for many years one of the most common storage media and favorite means of transferring data among ordinary users.

Flash storage capacity

Volume is one of the key characteristics of any data drive, since it directly depends on how much information can fit on the media. That is why most ordinary users, when buying a storage medium, primarily focus their attention on this parameter.

The first flash drives had rather modest volumes, which amounted to tens or hundreds of megabytes. Modern flash drives in this regard are far ahead of their predecessors, and today the minimum volume of a cheap USB drive can be considered 4 GB or even 8 GB, since there is practically no difference in price between them. At the moment, 16 and 32 GB are considered the most popular volumes, since the cost of such flash drives is still not high and is less than 1000 rubles.

As you probably already noticed, the amount of flash memory, like RAM, is a number obtained from two raised to the nth power (2 n). That is, each subsequent value is obtained by doubling the previous one. Therefore, already after 32 GB, the volumes of flash drives begin to grow rapidly, and along with them, their cost begins to grow very significantly. So if USB-drives with a size of 64 GB and a cost of about 1,500 rubles are still in active demand, then 128 GB flash drives can already have a price of over 3,000 rubles, which sharply reduces consumer interest in them.

But the producers did not stop there. Today, there are flash drives on the market with a capacity of 256 GB, and even 512 GB, which, in fact, are solid state drives (SSD) enclosed in a compact case. Their cost is already so high that it is simply incorrect to call them ordinary flash drives.

Communication speed

Despite the fact that the volume really matters, one of the most important parameters of any drive is the speed of its data exchange with the device to which it is connected. In the case of flash drives, this characteristic is formed from three components: read speed, write speed and connection interface.

The read speed of all flash drives is always higher than the write speed. However, in some cases the difference can be very large. Therefore, before choosing a USB drive, it is better to decide how it will be used. If the information on it is rarely updated, then of course you can close your eyes to the recording speed. In the most budget models, the maximum read speed usually ranges from 10 to 15 Mb / s, and the write speed - from 3 to 8 Mb / s. This option is better to choose if the flash drive is intended for the exchange or transfer of small files, such as documents.

But a flash drive with read speeds above 20-25 Mb / s and write speeds over 10-15 Mb / s can be called not very expensive, but at the same time a universal solution that is suitable for any task. There are flash drives with more attractive speed characteristics that make working with them a real pleasure. True, the price for such products is set accordingly.

As a rule, the maximum speed indicators affect the interface for connecting a flash drive, which can be of two types - USB 2.0 and USB 3.0. In the first case (2.0), we are dealing with a maximum bandwidth of 480 Mbps. Thus, the maximum read or write speed of a USB2.0 flash drive cannot exceed 60 Mb/s. In practice, manufacturers do not strive to reach this ceiling and endow their products with speeds barely exceeding 30 Mb / s.

As for the USB 3.0 interface, here the bandwidth reaches up to 5 Gb / s, which makes it possible to transfer data at a speed of 640 Mb / s. Of course, for flash drives, this is an exorbitant figure. Nevertheless, even if we do not take into account devices with a capacity of 256 and 512 GB, already now some solutions offer users over 220 Mb / s read speeds, and over 130 Mb / s storage speeds.

At the same time, the presence of a USB 3.0 interface in a flash drive is not a guarantee that it will have high speed characteristics. Buying a flash drive with USB 3.0 is most appropriate if the drive has read / write speeds above 60 MB / s. If not, then a USB 2.0 flash drive might be a better buy, both in terms of price and features. So in some situations there is no point in overpaying for a newfangled interface.

And the last nuance. It is important to understand that a flash drive with a USB 3.0 connector, in order to realize its full speed potential, must also be inserted into the device into the USB 3.0 connector. If your equipment does not have those, then you should again think about the advisability of buying a drive with such an interface.

Design decoration

In the classic version, the flash drive looks like an elongated rectangle or a flattened cylinder 5 to 8 cm long with a removable cap that covers the USB connector. However, modern flash drives can come in a wide variety of shapes and sizes, as well as ways to protect the connector.

In general, flash drives can be divided into four groups according to the type of connectors:

Classic . The connector is closed with a cap. Good and reliable choice. The only inconvenience is the possibility of losing the cap.

With retractable connector . They have one common disease. Over time, the mechanism that fixes the connector becomes loose, which makes it much more difficult to install the flash drive into the final device.

with swivel mechanism . A fairly reliable option, in addition to giving the flash drive an original look.

Open connector . Practical and reliable. The main disadvantage here is the possibility of contamination of the connector and the ingress of moisture on it.

Another important external quality of a flash drive is the material from which it is made. It must be selected taking into account the frequency of use and the degree of respect for it. The cases of these devices are plastic, metal and rubberized type. Plastic cases can be called the most unreliable. This is especially true for flash drives with a retractable connector. Flash drives with metal casings are reliable and often look solid. Although someone their weight may seem excessive. As for rubberized cases, they are designed to create optimal conditions that counteract shocks, shocks and prevent moisture from entering this technical device.

Now it has become fashionable to make souvenir flash drives, whose cases have a non-standard look, for example, in the form of some figures or various household items. But all this “beauty” can turn back to you, since there is an option that in most cases you will not be able to use such a USB drive due to the dimensions of its case. Please note that when you buy an irregularly shaped or thick flash drive, it may simply not fit next to other devices installed in adjacent USB connectors.

Secondary functionsUSB-drives

We have considered the main parameters for choosing drives, now let's move on to considering the auxiliary functions of these devices. In order to expand the market and increase the popularity of their products, some manufacturers are trying to give flash drives additional features. So modern USB drives can be integrated with a device activity indicator, which will make it possible to show the period of safe removal of the drive from the USB port, an electronic clock and even a flashlight. There may be a function that provides protection against data overwriting and the possibility of hardware encryption of information. You can also find a drive with a built-in fingerprint scanner or card reader.

By the way, immediately after buying a new drive, do not rush to format it, as it may contain useful auxiliary software. It can be both formatting utilities, such applications for organizing data backup.

Conclusion

So, now you know the main parameters, according to which you can now independently choose a USB drive for one purpose or another. The only thing we did not mention in this article is the manufacturers of these devices. In fact, there are many, and even a lot, especially if we take into account the many small unknown Chinese manufacturers united under the common name NONAME.

However, in conclusion, we will name a few leading players in this market, so that it is easier for you to navigate among the many foreign titles. The most widely represented and promoted in the Russian market are TRANSCEND, KINGSTON, SANDISK and SILICON POWER. No less popular are the products of A-DATA, CORSAIR, KINGMAX, VERBATIM, EMTEC, SMART BUY and some others. But in any case, when buying, first of all, be guided by the technical characteristics and external parameters of the flash drive, if you do not want to spoil your mood and get a product under a big name that will not meet your expectations.

Flash memory is a type of durable memory for computers that can be reprogrammed or electrically erased. Compared to Electrically Erasable Programmable Read Only Memory, actions can be performed on it in blocks that are in different places. Flash memory costs much less than EEPROM, which is why it has become the dominant technology. Especially in situations where stable and long-term data storage is required. Its use is allowed in a wide variety of cases: in digital audio players, photo and video cameras, mobile phones and smartphones, where there are special android applications on a memory card. In addition, it is also used in USB flash drives, traditionally used to save information and transfer it between computers. It has gained some notoriety in the gamer world, where it is often used in a blunder to store game progress data.

general description

Flash memory is a type that can store information on its board for a long time without using power. In addition, we can note the highest data access speed, as well as the best resistance to kinetic shock in comparison with hard drives. It is thanks to these characteristics that it has become so popular for devices powered by batteries and accumulators. Another indisputable advantage is that when flash memory is compressed into a solid card, it is almost impossible to destroy it by any standard physical means, so it can withstand boiling water and high pressure.

Low-level data access

The method of accessing data in flash memory is very different from that used for conventional views. Low-level access is provided through the driver. Ordinary RAM immediately responds to calls to read and write information, returning the results of such operations, but the design of flash memory is such that it takes time to think.

Device and principle of operation

At the moment, flash memory is widespread, which is created on single-transistor elements with a "floating" gate. This allows for greater storage density than DRAM, which requires a pair of transistors and a capacitor element. At the moment, the market is replete with various technologies for building basic elements for this type of media, which are developed by leading manufacturers. What distinguishes them is the number of layers, methods of recording and erasing information, as well as the organization of the structure, which is usually indicated in the title.

At the moment, there are a couple of types of microcircuits that are most common: NOR and NAND. In both, the storage transistors are connected to the bit buses - in parallel and in series, respectively. The first type has rather large cell sizes, and there is a possibility for fast random access, which allows programs to be executed directly from memory. The second one is characterized by smaller cell sizes, as well as fast sequential access, which is much more convenient if it is necessary to build block-type devices where large information will be stored.

In most portable devices, the SSD uses the NOR type of memory. However, now USB devices are becoming more and more popular. They use NAND memory. Gradually, it displaces the first.

The main problem is the fragility

The first samples of mass-produced flash drives did not please users with high speeds. However, now the speed of writing and reading information is at such a level that you can watch a full-length movie or run an operating system on your computer. A number of manufacturers have already demonstrated machines where the hard drive is replaced by flash memory. But this technology has a very significant drawback, which becomes an obstacle to replacing existing magnetic disks with this carrier. Due to the characteristics of the flash memory device, it allows erasing and writing information for a limited number of cycles, which is achievable even for small and portable devices, not to mention how often this is done on computers. If you use this type of media as a solid state drive on a PC, then a critical situation will come very quickly.

This is due to the fact that such a drive is built on the property of field-effect transistors to store in a “floating” gate, the absence or presence of which in the transistor is considered as a logical one or zero in the binary. Recording and erasing data in NAND memory are performed using tunneled electrons using the Fowler-Nordheim method. with the help of a dielectric. This is not required, which allows you to make cells of minimal size. But it is this process that leads to the cells, since the electric current in this case causes the electrons to penetrate the gate, overcoming the dielectric barrier. However, the guaranteed shelf life of such memory is ten years. The wear of the microcircuit occurs not due to reading information, but due to operations to erase and write it, since reading does not require changing the structure of the cells, but only passes an electric current.

Naturally, memory manufacturers are actively working towards increasing the service life of this type of solid-state drives: they are striving to ensure uniform write / erase processes across array cells so that some do not wear out more than others. Software paths are predominantly used to evenly distribute the load. For example, to eliminate this phenomenon, the technology of "wear leveling" is used. In this case, data that is often subject to changes is moved to the address space of the flash memory, so the recording is carried out at different physical addresses. Each controller is equipped with its own alignment algorithm, so it is very difficult to compare the effectiveness of certain models, since implementation details are not disclosed. Since the volume of flash drives is growing every year, it is necessary to apply more and more efficient algorithms to ensure the stability of the devices.

Troubleshooting

One of the very effective ways to combat this phenomenon was the reservation of a certain amount of memory, which ensures load uniformity and error correction through special logical redirection algorithms for replacing physical blocks that occur during intensive work with a flash drive. And to prevent the loss of information, cells that are out of order are blocked or replaced with backup ones. Such a software distribution of blocks makes it possible to ensure load uniformity by increasing the number of cycles by 3-5 times, but this is not enough.

And other types of such drives are characterized by the fact that a table with the file system is entered into their service area. It prevents failures in reading information at the logical level, for example, in the event of an incorrect shutdown or a sudden interruption in the supply of electrical energy. And since the system does not provide for caching when using removable devices, frequent overwriting has the most detrimental effect on the file allocation table and directory contents. And even special programs for memory cards are not able to help in this situation. For example, with a single access, the user rewrote a thousand files. And, it would seem, only once used for recording the blocks where they are located. But the service areas were overwritten with each update of any file, that is, the allocation tables went through this procedure a thousand times. For this reason, the blocks occupied by this particular data will fail first of all. Wear leveling technology works with such blocks, but its effectiveness is very limited. And it doesn’t matter what computer you use, the flash drive will fail exactly when it is provided by the creator.

It is worth noting that the increase in the capacity of the microcircuits of such devices only led to the fact that the total number of write cycles was reduced, as the cells become smaller, therefore, less and less voltage is required to dissipate the oxide partitions that isolate the “floating gate”. And here the situation is such that with an increase in the capacity of the devices used, the problem of their reliability has become more and more aggravated, and the class of the memory card now depends on many factors. The reliability of such a solution is determined by its technical features, as well as the current market situation. Due to fierce competition, manufacturers are forced to reduce the cost of production in any way. Including due to the simplification of the design, the use of components from a cheaper set, the weakening of control over manufacturing, and in other ways. For example, a Samsung memory card will cost more than lesser-known analogues, but its reliability raises much fewer questions. But even here it is difficult to talk about the complete absence of problems, and it is difficult to expect anything more from devices from completely unknown manufacturers.

Development prospects

Despite the obvious advantages, there are a number of disadvantages that characterize the SD-memory card, preventing further expansion of its scope. That is why there is a constant search for alternative solutions in this area. Of course, first of all, they try to improve the existing types of flash memory, which will not lead to any fundamental changes in the existing production process. Therefore, there is no doubt about only one thing: the companies involved in the manufacture of these types of drives will try to use their full potential before switching to another type, continuing to improve traditional technology. For example, the Sony memory card is currently available in a wide range of sizes, so it is expected that it will continue to be actively sold.

However, today a whole range of alternative data storage technologies is on the verge of industrial implementation, some of which can be implemented immediately upon the onset of a favorable market situation.

Ferroelectric RAM (FRAM)

Ferroelectric RAM (FRAM) technology is proposed to increase the potential of non-volatile memory. It is generally accepted that the mechanism of operation of existing technologies, which consists in rewriting data in the process of reading with all modifications of the basic components, leads to a certain restraint in the speed potential of devices. And FRAM is a memory characterized by simplicity, high reliability and speed of operation. These properties are now characteristic of DRAM - the non-volatile random access memory that exists at the moment. But this will also add the possibility of long-term data storage, which is characterized. Among the advantages of such a technology, resistance to various types of penetrating radiation can be distinguished, which may be in demand in special devices that are used to work in conditions of increased radioactivity or in space exploration. The information storage mechanism is implemented here through the use of the ferroelectric effect. It implies that the material is able to maintain polarization in the absence of an external electric field. Each FRAM memory cell is formed by placing an ultra-thin film of ferroelectric material in the form of crystals between a pair of flat metal electrodes that form a capacitor. The data in this case is stored inside the crystal structure. And this prevents the effect of charge leakage, which causes the loss of information. The data in the FRAM memory is retained even when the power supply is switched off.

Magnetic RAM (MRAM)

Another type of memory that is considered very promising today is MRAM. It is characterized by rather high speed performance and energy independence. in this case, a thin magnetic film placed on a silicon substrate is used. MRAM is a static memory. It does not need to be periodically overwritten, and the information will not be lost when the power is turned off. At the moment, most experts agree that this type of memory can be called the next generation technology, since the existing prototype demonstrates fairly high speed performance. Another advantage of this solution is the low cost of the chips. Flash memory is manufactured according to a specialized CMOS process. And MRAM chips can be produced using a standard manufacturing process. And the materials can be those that are used in conventional magnetic media. It is much cheaper to produce large batches of such microcircuits than all the others. An important property of MRAM memory is the ability to turn on instantly. And this is especially valuable for mobile devices. Indeed, in this type, the value of the cell is determined by the magnetic charge, and not by the electric charge, as in traditional flash memory.

Ovonic Unified Memory (OUM)

Another type of memory that many companies are actively working on is the solid-state drive based on amorphous semiconductors. It is based on the phase transition technology, which is similar to the principle of recording on conventional discs. Here the phase state of matter in an electric field changes from crystalline to amorphous. And this change persists even in the absence of tension. Such devices differ from traditional optical discs in that the heating occurs due to the action of an electric current, and not a laser. Reading in this case is carried out due to the difference in the reflectivity of the substance in different states, which is perceived by the drive sensor. Theoretically, such a solution has a high storage density and maximum reliability, as well as increased speed. The indicator of the maximum number of rewriting cycles is high here, for which a computer is used, the flash drive in this case lags behind by several orders of magnitude.

Chalcogenide RAM (CRAM) and Phase Change Memory (PRAM)

This technology is also based on the basis when in one phase the substance used in the carrier acts as a non-conductive amorphous material, and in the second it serves as a crystalline conductor. The transition of the storage cell from one state to another is carried out due to electric fields and heating. Such chips are characterized by resistance to ionizing radiation.

Information-Multilayered Imprinted Card (Info-MICA)

The operation of devices built on the basis of this technology is carried out according to the principle of thin-film holography. Information is recorded as follows: first, a two-dimensional image is formed, which is transferred to a hologram using CGH technology. Data is read by fixing the laser beam on the edge of one of the layers being recorded, which serve as optical waveguides. The light propagates along an axis that is parallel to the plane of the layer, forming an output image corresponding to the information recorded earlier. The initial data can be obtained at any time thanks to the reverse coding algorithm.

This type of memory compares favorably with semiconductor memory due to the fact that it provides high recording density, low power consumption, as well as low media cost, environmental safety and protection from unauthorized use. But such a memory card does not allow information to be rewritten, therefore it can only serve as a long-term storage, a replacement for paper media, or an alternative to optical discs for distributing multimedia content.