Electronic storage media and their characteristics.  Evolution of storage media

May 2009

The more digital technology becomes a part of office life, the more actively they begin to use a wide variety of media. Floppy disks were the first to appear on the office goods market, then they were supplemented byCD andDVDs and flash drives are now confidently coming into use. Undoubtedly, in a number of cases, certain information storage devices turn out to be much more effective, and in some cases even an indispensable tool for working with various materials, which leads to an increase in demand for this type of product in the office segment and, accordingly, the introduction into the range and gradual expansion lines of storage media by operators of the office goods market. Read about the situation in this segment of computer accessories, supply features, demand trends and development prospects in the current product review.

General situation

“Data storage media” are one of the most dynamically developing product groups: no sooner had the first floppy disks appeared than manufacturers introduced the next type of product - CDs and DVDs, and then USB drives and memory cards, external hard drives. What was previously often perceived as a “luxury” in work is now becoming the norm of life and an unchangeable attribute, as natural as pen or paper. That is why stationery companies have recently begun to introduce and develop the “Information Media” product line into their assortment, although in fairness it should be noted that not all players in the stationery and office market can “boast” of a good selection of this type of product in their assortment.

Nevertheless, there is a growing interest in this group of products among stationery market operators, as evidenced by experts from companies specializing in the distribution of computer equipment and accessories and supplying storage media, including to office workers.

“Currently, the share of office supply companies offering storage media is small,” notes product manager for flash products at AKCent" Sergey Roshchin. “Although in the near future it may be significantly expanded due to the fact that flash drives are beginning to move from the category of computer accessories to the category of consumables vital for the operation of a modern office.”

“Among our clients there are many office supply companies and they occupy a significant share in the Information Media group,” says manager of the business development department of the Merlion company Olga Shipulina. “In the near future, their share will most likely only grow, as storage media are increasingly moving into the office stationery segment from the segment of technically complex goods,” she continues. - First of all, this applies to flash memory, as well as high-capacity USB hard drives - from 160 GB to 2 TB. This is the fastest growing segment, which has shown significant growth over the past six months to a year.”

The rapid development of the “Flash Drives” group as one of the “Information Media” segments and the tendency for them to displace other information media is also noted Sergey Roshchin (“AK Cent”), noting that they are increasingly competing with CDs and DVDs, especially in the low price segment.

Since storage media is a relatively new product for stationery market operators, it cannot be said that it is saturated with this type of product. “The market saturation is low and many companies represent this segment rather narrowly,” states Head of the office equipment department of SAMSON Group of Companies Alexey Tokarev. - Although our company’s assortment includes almost the entire range of storage media - floppy disks, CD-R/RW-, DVD-R/RW-disks, memory cards, and USB drives, and in the near future it is planned to introduce portable hard drives. “As for flash drives, the market is also far from saturated,” adds Sergey Roshchin (“AK Cent”).

Perhaps this is why storage media are the most profitable group in the Computer Accessories segment, as experts also testify. “In the Computer Accessories segment, the Storage Media group is one of the most profitable,” notes Alexey Tokarev (“SAMSON”). “Flash cards, USB drives and external HDD and SSD drives make up more than half of our product range and clearly lead in terms of profit,” states Sergey Roshchin (AKCent"). “Profitability in this segment is traditionally good, and this is also why the product group is developing dynamically,” confirms Olga Shipulina (“Merlion”).

Players & Features of Demand

Diagram 1. Shares of different consumer groups in the total flow of demand for storage media (according to the AK Cent company)

The composition and shares of players in different media subgroups vary. If we talk about the “Floppy Diskettes” subgroup, then, according to Alexey Tokarev (“SAMSON”), the most popular brands are Verbatim, Imation, Emtec/BASF, TDK, SONY. “The leader is the Verbatim brand, whose products account for approximately 25% of all sales,” he adds.

“The market for recordable optical media (CD/DVD discs) is divided into two segments: no name discs and products from well-known companies such as TDK or Verbatim. In the first segment, only price matters, and in the second, the emphasis is on brand image,” he continues.

If we talk about the “Flash drives” group, then here, as stated by Sergey Roshchin (“AK Cent”), the leading brands are Transcend and Kingston, which each occupy approximately 30% of the flash memory market. “Next are brands such as Sony - 10%, Apacer - 7%, A-Data - 5%, as well as a number of others, whose share is in the range of up to 5%: OCZ, SanDisk, PQI, etc.,” - he adds.

Sergey Roshchin: Do you remember the last time you bought pens or post-it blocks for your home? For what? After all, they are given out at work with the company logo. The same will soon happen with USB drives. It’s just that they won’t have the manufacturer’s logo on them.

According to Olga Shipulina (“Merlion”), the picture with the distribution of shares between players today is not so clear. “In the current unstable situation, it is impossible to say anything with certainty about shares or about the existing demand and market segments, and the Information Media group is no exception,” she notes. “Nowadays, products from cheap brands are becoming increasingly in demand, since in addition to low prices, they also now offer good designs and have improved in product quality.”

In addition to foreign players, domestic manufacturers also present their products on the Russian market. However, as rightly noted Sergey Roshchin (“AK Cent”), there is no need to talk about their significant share. “In most cases these are Private Labels of domestic distributors and retailers,” he adds.

The competition between players is quite tough. “In the flash memory market, this is due to a fairly large number of distributors and the predominance of price competition in the market,” analyzes Sergey Roshchin (“AK Cent”). “In the low price segment of capacities up to 2 GB, competition is so intense that many distributors work exclusively with the most popular items in the middle and upper price ranges,” he continues. - As for our company, we try to maintain the maximum range of products for each vendor, which, coupled with an attractive price, allows us to maintain a leading position in the market for many years. Regarding no name products, we can say that its main consumers are advertising agencies and the corporate sector involved in applying their own logos to these flash drives. Now flash drives with the company logo are becoming a fairly common element of corporate style, along with pens and diaries.”

Scheme 1. Classification of storage media

Quite strong competition also exists in the segment of CDs and DVDs, and the main struggle is also between branded and no name products. Perhaps the calmest situation in this regard remains in the segment of floppy disks, which, due to their low cost and limited demand, are not of particular interest to manufacturers of non-branded products.

Analyzing the distribution of demand for flash drives, Sergey Roshchin (“AK Cent”) notes that, according to a rough estimate, Moscow and the region account for up to 60-70% of demand, the rest comes from other regions. “However, smaller distribution companies purchasing goods in Moscow are engaged in further distribution of goods, including in the regions,” he notes. - The same can be said about federal retail and cellular networks. Therefore, we can roughly estimate the shares of flash consumption in Moscow, the Moscow region and other regions of Russia as equal.”

The growth in demand for storage media in the regions is evidenced by Olga Shipulina (“Merlion”). “There was pent-up demand in the regions when consumers began to buy high-tech goods and, accordingly, the demand for storage media increased,” she states.

Speaking about the peculiarities of demand for storage media, Sergey Roshchin (“AK Cent”) draws attention to the fact that the demand for flash memory has a pronounced seasonality. “In the spring-summer period, sales of flash cards predominate, and in the autumn-winter period, sales of USB drives predominate,” he explains. “This is partly due to the specifics of using these devices: in the summer, during the holidays, cards for cameras and phones are needed, and in the fall, schoolchildren and students buy USB drives for data exchange.”

At the same time, it is in the flash drive segment, as the most dynamically developing and most expensive segment, that today we can speak of the highest level of requirements for product quality. Although, according to Sergei Roshchina (“AK Cent”), and it is not the main one. “Most flash drives become morally obsolete much faster than they physically fail, and the warranty period for some of them extends for the entire period of operation,” he explains. “In general, for flash cards, the indicator of quality is the data transfer speed, for USB drives - the design and quality of its execution: material, assembly, sometimes even packaging.”

Floppy disks

“At the end of the last decade, computer market experts unanimously assured: the time of 3.5-inch floppy disks or, in other words, floppy disks is running out - in another year or two, and they will be completely ousted from the market,” says Alexey Tokarev (“SAMSON”). “The floppy disk market is indeed shrinking, but much slower than predicted.”

Today, according to Alexey Tokarev (“SAMSON”), the volume of the Russian floppy disk market ranges from 2 to 3 million media per month. “Experts cite several reasons for the continued popularity of floppy disks,” he continues. - Firstly, it is quite low cost compared to alternative devices such as flash memory and magnetic-optical disks. Secondly, floppy disks are often used to store information that can be used to restore a computer to its functionality after a failure. But the most important reason for the “survivability” of floppy disks is, perhaps, the low cost of disk drives, selling for no more than $10,” he concludes.

One way or another, floppy disks today have retained several niches that allow them to occupy a relatively stable market share. Demand for them is maintained thanks to:

Government agencies in which the computer equipment fleet is very budgetary, and therefore 3.5" floppy disks are used for file exchange;

Individual universities, especially peripheral ones, in which students resort to using floppy disks as a practically unalternative means for transferring coursework or other work;

Some areas (for example, banking) where software is still used that requires a key floppy disk to access the program or any data;

For computer “enthusiasts” who sometimes keep a floppy drive in their computer, since all operating systems before Windows XP receive drivers (at the installation stage) only from a floppy disk, and it is easier to create a bootable flash drive for Windows XP by first making a boot floppy disk.

Diagram 2. Share of different types of drives in the companies’ assortment

Thanks to these groups, floppy disks and floppy disk drives remain quite popular products today.

In the assortment of companies you can find black or assorted floppy disks (green, red, yellow, blue, orange, etc.) in packaging. They can be sold both in cardboard packages and in plastic boxes. However, all these “delights” do not have a significant impact on demand today. The most popular are the classic black floppy disks, packaged in a more economical cardboard box.

Discs

The demand for CDs and DVDs is much higher than for floppy disks, although it can be noted that with the proliferation of higher-capacity DVDs, the demand for CDs has “froze.” “The share of CDs has been declining in recent years, and no wonder. These media are no longer enough for large volumes of information, for example, for video, and the price of “blanks” is almost equal to the prices for more capacious storage media,” states Alexey Tokarev (“SAMSON”). “And drives that don’t support DVDs are slowly becoming history,” he continues. “However, in absolute terms, the supply of such media is still very high. This is largely due to the fact that a large number of household equipment purchased earlier do not understand other formats. In other words, if we need compatibility with an old household player or radio, then we need to buy a CD. And in general, in terms of ensuring maximum compatibility, this format remains the most optimal: any optical drive will read a CD. Plus, laptops with a combo drive are still sold, so their owners have no choice if they want to record something on the “optics,” he concludes.

Both optical storage media have their own advantages, and each gradually occupies its own niche in the market. CDs have more storage capacity than floppy disks and are not as expensive as DVDs. Therefore, they are the best option for recording and mass distribution of presentations, training programs, catalogs, advertising materials, supplements to printed publications, as well as for creating archives, etc., which allows them to remain the sales leader in the “floppy disk - CD” line -disks - DVDs” (see Diagram 4). DVDs are used in areas where you have to work with large volumes of documents (for example, in design and engineering departments).

Blu-ray disc (BD-disc)
Blu-ray technology uses a blue-violet laser with a wavelength of 405 nm to read and write. Conventional DVDs and CDs use red and infrared lasers with wavelengths of 650 nm and 780 nm, respectively. Reducing the wavelength in Blu-Ray technology has made it possible to narrow the recording track by half compared to a conventional DVD and increase the data recording density. In other words, the shorter wavelength of the blue-violet laser allows more information to be stored on a 12 cm Blu-Ray disc than on a CD/DVD of the same size.

If we analyze the range of CDs and DVDs offered today on the office goods market, we can note that the products are presented quite widely. These are, as a rule, several brands and no name products, covering all price segments and, accordingly, different types of packaging with different numbers of discs in the packaging itself.

The range of disposable CDs and DVDs is the most widely represented (when compared with the line of reusable discs): both in terms of the number of pieces in the package, the type of packaging, color, and the ability to print on the surface of the disk.

In the assortment of CD-R and DVD-R (single-use) discs, in terms of quantity per package, the largest number of positions are most often found in packages of 10 discs. The products are also widely represented in packages of 25, 50 and 100 discs. At the same time, cakebox is increasingly becoming the most popular type of packaging as it is cheaper, and for large “batches” of 50 and 100 discs, practically the only possible one. However, storing archival materials in “cakeboxes” in offices is quite inconvenient, as it makes it difficult to find and remove the desired disk from the total mass of “blanks” strung on top of each other, like in a children’s pyramid.

Some companies offer discs in shrink packaging, in which the discs are packaged by quantity and enclosed in regular shrink film - this is perhaps the most economical type of packaging, but is quite rare in the supplier's product line. Such “blanks” will definitely require additional costs for storage accessories - either plastic cases, or pockets for discs, or cases and special boxes.

Discs in jewel (“thick”) and slim (“thin”) plastic cases are usually offered in cardboard packages with a capacity of up to 10 pieces. According to Alexey Tokarev (“SAMSON”), slim cases are more compact and cheaper, so they are in greater demand. In general, the advantage of discs in cases is that they can be sold without any problems both in packages and individually - the case will protect the “blank” from mechanical damage during transportation and will relieve the client from the need to solve the problem of “what to wrap and put in” .

Among disposable discs, media with the ability to print on a surface are of particular interest. As noted Alexey Tokarev (“SAMSON”), this type of optical media is in demand in the corporate segment.

CD-RW and DVD-RW (reusable) discs are usually offered in much smaller quantities per package and more often - individually and in jewel cases, since this type of box maximally protects optical storage media from damage.

It was the “reusable” nature of the disks that determined the noticeably lower demand for them. Firstly, they can be used several times, and, accordingly, the need to repurchase them arises much less frequently; secondly, they are, of course, more expensive than disposable disks, so they are purchased specifically when there is a deliberate need to record several once. And if you consider that more “advanced” storage media, colloquially referred to as “flash drives,” are widely available on the market and at reasonable prices, which allow you to record much larger volumes of information, a significantly larger number of times, while the devices themselves are undoubtedly more compact disks, and the information on them is more protected from mechanical influences. All this ultimately leads to the fact that consumers are increasingly choosing flash drives.

For the same reason, double-sided discs are less common. “The demand for them is quite limited due to the fact that they are expensive and at the moment there are other media that can provide a larger volume of information storage,” notes Alexey Tokarev (“SAMSON”).

Another existing type of disc is Blu-Ray or BD (from the English blue ray - “blue ray”) - an optical media format used for recording and storing digital data, including high-definition video with increased density. This type of storage media is also present in the assortment of some companies, but has not yet become widespread for a number of reasons. “It’s hard to say about the prospects for BD discs,” comments Olga Shipulina (“Merlion”)“I think they are in demand and will remain in demand only in the segment of licensed films, games and other content sold only on discs.”

According to Alexey Tokarev (“SAMSON”), drives for BD discs are becoming more widespread, the discs themselves are becoming cheaper, so in the next couple of years “the promotion of the format will continue.”

Flash drives, memory cards, portable hard drives

This segment of storage media, according to Sergei Roshchin (“AK Cent”), is distinguished by a constant downward price trend and a constant increase in the storage capacity of digital media themselves. “Six months ago, the main sales were in media with capacities of 1 GB and 2 GB, now the most popular volumes are already 2 GB and 4 GB, and 1 GB has practically disappeared from the range,” he comments. “It is likely that by the end of the year it will be difficult to find a USB drive with a capacity of 2 GB, and 4 GB and 8 GB will be the best sellers.”

Alexey Tokarev (“SAMSON”), characterizing the specifics of the segment, adds that unlike “optics”, where there is a simple redistribution of market shares, the flash drive segment is growing on its own. “The proliferation of digital cameras, flash camcorders and other digital devices suggests significant growth in flash card sales,” he adds.

According to Olga Shipulina (“Merlion”), the main advantage of flash memory over hard drives and CD-ROM media is that it consumes significantly (about 10-20 times or more) less energy during operation. “In addition, flash memory is more compact than most other mechanical media, more reliable and durable,” she notes. “Information recorded on it can be stored from 20 to 100 years and can withstand significant mechanical loads, 5-10 times longer than the long-term permissible for conventional hard drives.”

Types of Flash Drives

	USB Flash Drive or USB flash drive (flash drive, USB drive or “flash drive”)- a storage medium that uses flash memory to store data and is connected to a computer or other reading device via a standard USB connector. It is the latter that distinguishes this type of storage media from memory cards.
	Multimedia Card (MMC)- portable memory card used in digital cameras, mobile phones, etc. Size 24x32x1.5 mm. Developed jointly by SanDisk and Siemens. The MMC contains a memory controller and is highly compatible with a wide variety of devices. Typically, MMC cards are supported by devices with an SD slot. Three additional modifications of MMC cards: RS-MMC, MMCmobile and MMCmicro, which require an adapter to ensure compatibility with a standard MMC slot. RS-MMC(Reduced Size MultiMedia Card): half as long as a standard MMC card (reduced size = “reduced size”): 18x24x1.4 mm. All other characteristics do not differ from those of a “regular” MMC card. DV-RS-MMC(Dual Voltage Reduced Size MultiMedia Card): DV-RS-MMC memory cards with dual voltage (dual voltage: 1.8 and 3.3 V) have lower power consumption and allow the device to operate a little longer. Dimensions are the same as RS-MMC. MMCmicro: miniature memory card for mobile devices with even smaller dimensions than RS-MMC: 12x14x1.1 mm.
	SD Card(Secure Digital Card) - supported by SanDisk, Panasonic and Toshiba. It is a further development of the MMC standard. In size and characteristics they are very similar to MMC, only slightly thicker (24x32x2.1 mm). The main difference is copyright protection technology (secure digital), which allows you to protect access to the card with a password. Unlike MMC cards, SD cards are also equipped with a mechanical switch to protect information from writing information, deleting files, and formatting the card. This type of protection is assigned to the device working with the card, so it may not be implemented. In most cases, SD can be replaced with an MMC card. Reverse replacement is usually not possible due to the thickness of SD cards. There are 2 modifications of SD cards: SDTF(Trans-Flash) and SDHC(High Capacity = “high capacity”) - SDTF and SDHC cards and their reading devices differ in the limitation on the maximum storage capacity - up to 2 GB for TF and up to 32 GB for HC. SDHC readers are backward compatible with SDTF and will easily read an SDTF card, but an SDTF device will only see 2 GB of the capacity of an SDHC, if it has a larger capacity, or will not be read at all. Both subformats can be of three sizes: standard SD (24x32x2.1 mm), miniSD (20x21.5x1.4 mm) and microSD (11x15x1 mm). To ensure compatibility with a standard SDmini and micro slot, an adapter is required.
	Memory Stick (MS)- a storage medium based on flash memory technology from Sony Corporation. Memory Stick memory cards are used in camcorders, digital cameras, personal computers, printers, PSP game consoles, cell phones and other electronic devices primarily from Sony itself. Standard dimensions: 21.5x50x2.8 mm. MS Duo/MS Pro Duo- have smaller dimensions (20x31x1.6 mm) and higher information transfer rates (up to 20 Mb/s). MSmicro- has even smaller dimensions (12.5x15x1.2 mm).
	CompactFlash (CF)- a flash memory format that was one of the first to appear. Developed by SanDisk. Used in pocket computers, digital video and photo cameras, printers, etc. Dimensions: 43x36x3.3 mm. One of the most important advantages of CF is its compatibility with the PCMCIA-ATA standard, the most common for small-sized devices.
	Smart Media (SM)- format developed by Toshiba. Unlike CF, SM cards do not have a built-in controller, which somewhat worsens compatibility - older devices do not always understand high-capacity cards. Dimensions: 37x45x0.76 mm. Memory cards of this format are currently out of production.
	eXtreme Digital (хD), the new name is xD-Picture Card - the format is designed for use in Olympus and Fuji digital cameras. Other brands that make xD cards include Kodak, SanDisk and Lexar. Designed as a replacement for the Smart Media format. Compared to SM, the xD format is more universal, compact (size 20x25x1.7 mm), has a higher data transfer rate, reduced power consumption and greater capacity. Unlike SD/MMC cards, xD cards are not equipped with a controller chip, and therefore have a relatively small size and low speed characteristics compared to SD/MMC cards. The cost of xD cards is on average twice the cost of SD cards of the same capacity, despite the fact that XD cards do not have any special advantages over SD cards.

There are several types of flash drives. All of them can be divided into 3 groups: flash drives (or simply “flash drives”), memory cards and SSDs, which are often considered together with magnetic external HDD drives.

As noted Olga Shipulina (“Merlion”), for the office the most popular are flash drives and external HDD and SSD drives. “Cards are less popular because they are used more actively in multimedia devices: phones, smartphones, PDAs, photo and video equipment,” she adds.

SSD drive
(from the English SSD, Solid State Drive, Solid State Disk) - a solid-state drive, a rewritable computer storage device without moving mechanical parts (unlike HDD). There are solid state drives based on the use of volatile (RAM SSD) and nonvolatile (NAND or Flash SSD) memory. The “stuffing” of an SSD physically has nothing in common with traditional hard drives (HDD) and is an array of flash memory with a hard drive interface and access to a PC (via traditional SATA or PATA interfaces). It differs from HDD in appearance only in its more compact dimensions. SSDs have all the advantages and disadvantages of flash memory.

“Flash drives are the leaders among USB drives - 80%,” states Sergey Roshchin (“AK Cent”). - Portable external hard drives (HDDs) are also finding their buyers, which offer larger capacities (up to 1000 GB) with the convenience of regular USB drives - 15%. The mass distribution of the latest SSD solid-state drives is still limited by the relatively high price compared to HDDs; their share of the USB drive market is still only 5%, but this type of media has very great potential for development, since they have a USB interface and HDD capacity -disk and flash memory, in contrast to HDD drives, which have mechanical elements.”

Diagram 3. The ratio of USB drives and memory cards in the range of companies

“Among flash cards, the undisputed leader is micro CD - about 50% of all card sales - since they are used in almost every mobile phone,” continues Sergey Roshchin (“AK Cent”). - Further, the most significant are Secure Digital memory cards, used in professional photographic equipment and communicators - 30%, MemoryStick (MS Pro Duo and MS Micro M2) due to lobbying by SONY - 10%, and Compact Flash - 7%. The remaining standards are now practically “extinct,” he states. “However, as an office option, MS Pro Duo and SD cards will be more interesting, which can be used to expand the memory of laptops and netbooks and, accordingly, their capabilities, since the capacity of flash media is sometimes comparable to the capacity of the built-in disk.”

In assessing the parameters that influence clients’ choice of certain devices, experts disagreed ( see Table 1). Moreover, the evaluation of the parameters itself also caused difficulties, since their importance varies in different situations, in relation to different types of flash drives and in different market segments. Thus, according to Sergei Roshchin (AK Cent), such a parameter as a brand turns out to be important mainly for corporate customers who have increased requirements for reliability, for example, for banks or for tender deliveries, where a specific brand is clearly stated. “And in retail, the brand that is usually sold is the one that is on the shelf and which is advertised by a skillful consultant,” he adds.

Moreover, as stated Sergey Roshchin (“AK Cent”), it is difficult to determine the significance of such a parameter as the “capacity” of the drive. “As a rule, the end user buys a flash drive with the maximum possible capacity that fits into the amount that he can afford to spend on it, regardless of whether this amount is relevant now or not,” he explains.

It is interesting to note that, unlike the demand for many other office products, the demand for storage media such as flash drives is often determined by packaging. “Packaging/blister - bright, stylized - is sometimes much more important than the brand and is on par with the design of the flash drive itself,” emphasizes Sergey Roshchin (“AK Cent”). - Regarding product design, we can say that in the office segment, drives in a strict design and in classic colors and materials are more in demand - a simple plastic rectangle in black or corporate color. However, “flash drives” of original design are often used as representative functions, for example, drives stylized as company products, or “flash drives” with expensive, exclusive body finishes - for example, made of genuine leather or with Swarovski crystals.” The importance of the materials from which the body of the product is made is evidenced by Olga Shipulina, arguing that they influence the choice of a particular drive in the same way as the brand and country of origin.

Diagram 4. The ratio of sales volumes of CD-/DVD-disks, floppy disks in 2008 in the assortment of the SAMSON Group of Companies

Experts also point out that small flash drives are not so convenient to use, and although they are present in the range of companies, they are in limited demand. “The very small size of a flash drive is more of a publicity stunt than a demanded necessity, and has a number of disadvantages: lower strength of the case, insecurity of the USB connector, and, trivially, such a flash drive is much easier to lose and more difficult to find in a pocket or bag,” - explains Sergey Roshchin (“AK Cent”).

Such a parameter as the speed of information exchange (read/write), according to Sergei Roshchin (“AK Cent”), does not significantly affect the choice of USB drive and is of greatest importance mainly when purchasing Compact Flash cards used in professional photographic equipment. “In other cases, the more important argument is price,” he adds. - At the same time, an increase in prices for similar products usually leads to a shift in demand for cheaper analogues, if these are mutually competing brands, such as Transcend and Kingston. Design and brand image play a less significant role here.”

There are a few basic rules to remember when working with memory cards:

• Electrostatic discharge can damage electronic components, so before touching the memory card, you should make sure that you are not exposed to static electricity by touching a grounded metal object;
• Avoid touching the gold-plated contacts of the memory card;
• It is necessary to protect the memory card from heat sources, direct sunlight, and humidity;
• Do not bend or throw the memory card;
• You should never disconnect the memory card while transferring information to avoid data loss or damage to the card itself;
• Before use, it is better to make sure that the card and device are compatible.

Regarding the capacity of flash drives, as noted earlier, drives with a capacity of 2 GB and 4 GB are currently the most popular, and models with a capacity of 8 GB are currently considered the most promising. Although, as stated Sergey Roshchin (“AK Cent”), the presence of higher-capacity flash drives in the assortment is also necessary for a complete assortment and the user’s gradual “getting used to” them.

Diagram 5. Share of USB drives of different capacities in the range of companies

Conclusion

All experts admit that disks, like floppy disks, will soon, if not become a thing of the past, then be significantly replaced by flash drives. “The dynamics of demand will shift towards USB flash drives and inexpensive large-capacity memory cards, as well as inexpensive portable USB HDDs with a capacity of up to 500 GB,” predicts Olga Shipulina (Merlion). And many factors, in her opinion, will contribute to this process: the filling of the market with all kinds of devices that allow the use of memory cards, and the displacement of disks by flash drives and small SSD/HDDs, and the greater versatility and ease of use of these devices for all categories of consumers , and greater protection of recorded information from mechanical influences.

Sergey Roshchin (AK Cent) shares the same opinion, noting that the segment of flash storage media is just beginning to take shape. “As the offered storage capacity of storage media increases and the cost decreases, USB flash drives can significantly displace CDs as a tool for storing and transmitting information outside the company (presentations, advertising, etc.),” he comments. - Without a doubt, this “souvenir” will be used repeatedly, unlike a disk, and this is a serious argument in favor of flash drives. Moreover, many modern laptops are starting to get rid of built-in DVD drives. And even “office blondes” understand the process of recording onto a USB flash drive, which cannot be said about recording a CD or DVD.”

Such a group of drives as flash drives for applying information to the case has particular prospects. “Pretty soon, in most companies, every employee will have a flash drive with the company logo and a small presentation, just like a pen and business cards,” predicts Sergey Roshchin (AKCent"). “And their sales to the corporate sector will probably be comparable to retail sales.”

We thank the companies “AK Cent”, “Merlion”, “SAMSON” for their assistance in preparing the product review.

ATTENTION!
Here is a very abbreviated text of the abstract. The full version of the computer science essay can be downloaded for free from the link above.

Types of storage media

Storage medium– physical environment that directly stores information. The main carrier of information for a person is his own biological memory (the human brain). A person’s own memory can be called operative memory. Here the word “operative” is synonymous with the word “fast”. Memorized knowledge is reproduced by a person instantly. We can also call our own memory internal memory, since its carrier - the brain - is located inside us.

Storage medium- a strictly defined part of a specific information system that serves for intermediate storage or transmission of information.

The basis of modern information technology is the computer. When it comes to computers, we can talk about storage media as external storage devices (external memory). These storage media can be classified according to various criteria, for example, by type of execution, material from which the media is made, etc. One of the options for classifying information carriers is presented in Fig. 1.1.

List of storage media in Fig. 1.1 is not exhaustive. We will look at some storage media in more detail in the following sections.

Tape media

Magnetic tape- a magnetic recording medium, which is a thin flexible tape consisting of a base and a magnetic working layer. The operating properties of magnetic tape are characterized by its sensitivity during recording and signal distortion during recording and playback. The most widely used is multilayer magnetic tape with a working layer of needle-shaped particles of magnetically hard powders of gamma iron oxide (y-Fe2O3), chromium dioxide (CrO2) and gamma iron oxide modified with cobalt, usually oriented in the direction of magnetization during recording.

Disk storage media

Disk storage media refer to direct access machine media. The concept of direct access means that the PC can “access” the track on which the section with the required information begins or where new information needs to be written.

Disk drives are most diverse:

• Floppy magnetic disk drives (FMD), also known as floppy disks, also known as floppy disks
• Hard magnetic disk drives (HDDs), also known as hard drives (popularly just “screws”)
• Optical CD drives:
• CD-ROM (Compact Disk ROM)
• DVD-ROM

There are other types of disk storage media, for example, magneto-optical disks, but due to their low prevalence we will not consider them.

Floppy disk drives

Some time ago, floppy disks were the most popular means of transferring information from computer to computer, since the Internet in those days was very rare, computer networks too, and devices for reading and writing CDs were very expensive. Floppy disks are still used today, but quite rarely. Mainly for storing various keys (for example, when working with a client-bank system) and for transmitting various reporting information to government supervisory services.

Diskette- a portable magnetic storage medium used for repeated recording and storage of relatively small data. This type of media was especially common in the 1970s and early 2000s. Instead of the term “floppy disk”, the abbreviation GMD is sometimes used - “flexible magnetic disk” (accordingly, a device for working with floppy disks is called NGMD - “floppy magnetic disk drive”, the slang version is floppy drive, flopik, flopper from the English floppy-disk or in general " cookie"). Typically, a floppy disk is a flexible plastic plate coated with a ferromagnetic layer, hence the English name “floppy disk”. This plate is placed in a plastic case that protects the magnetic layer from physical damage. The shell can be flexible or durable. Floppy disks are written and read using a special device - a floppy drive. A floppy disk typically has a write-protect feature that allows read-only access to the data. The appearance of a 3.5" floppy disk is shown in Fig. 1.2.

Hard disk drives

Hard drives such as hard drives are widely used in PCs.

Term Winchester arose from the slang name for the first model of a 16 kV hard drive (IBM, 1973), which had 30 tracks of 30 sectors, which coincidentally coincided with the 30/30 caliber of the famous Winchester hunting rifle.

Optical drives

CD(“CD”, “Shape CD”, “CD-ROM”, “CD ROM”) - an optical storage medium in the form of a disk with a hole in the center, information from which is read using a laser. The compact disc was originally created for digital audio storage (the so-called Audio-CD), but is now widely used as a general-purpose data storage device (the so-called CD-ROM). Audio CDs are a different format from data CDs, and CD players can usually only play them (a computer can, of course, read both types of discs). There are discs containing both audio information and data - you can listen to them on a CD player or read them on a computer.

Optical discs They usually have a polycarbonate or glass heat-treated base. The working layer of optical disks is made in the form of the thinnest films of low-melting metals (tellurium) or alloys (tellurium-selenium, tellurium-carbon, tellurium-selenium-lead, etc.), organic dyes. The information surface of optical disks is covered with a millimeter-thick layer of durable transparent plastic (polycarbonate). In the process of recording and playback on optical discs, the role of a signal converter is performed by a laser beam focused on the working layer of the disc into a spot with a diameter of about 1 micron. As the disk rotates, the laser beam follows along the disk track, the width of which is also close to 1 μm. The ability to focus the beam into a small spot makes it possible to form marks with an area of ​​1-3 microns on the disk. Lasers (argon, helium-cadmium, etc.) are used as a light source. As a result, the recording density is several orders of magnitude higher than the limit provided by the magnetic recording method. The information capacity of an optical disk reaches 1 GB (with a disk diameter of 130 mm) and 2-4 GB (with a diameter of 300 mm).

Also widely used as an information carrier Magneto-optical CDs RW (Re Writeble) type. Information is recorded on them by a magnetic head with the simultaneous use of a laser beam. The laser beam heats a point on the disk, and the electromagnet changes the magnetic orientation of this point. Reading is performed with a laser beam of lower power.

In the second half of the 1990s, new, very promising carriers of documented information appeared - digital universal video disks DVD (Digital Versatile Disk) such as DVD-ROM, DVD-RAM, DVD-R with large capacity (up to 17 GB).

Based on application technology, optical, magneto-optical and digital compact discs are divided into 3 main classes:

1. Disks with permanent (non-erasable) information (CD-ROM). These are plastic CDs with a diameter of 4.72 inches and a thickness of 0.05 inches. They are made using an original glass disk on which a photorecording layer is applied. In this layer, the laser recording system forms a system of pits (marks in the form of microscopic depressions), which is then transferred to replicated copy disks. Information is also read by a laser beam in the optical drive of a personal computer. CD-ROMs usually have a capacity of 650 MB and are used for recording digital audio programs, computer software, etc.;
2. Discs that allow one-time recording and repeated playback of signals without the possibility of erasing them (CD-R; CD-WORM - Write-Once, Read-Many - recorded once, counted many times). They are used in electronic archives and data banks, in external computer storage devices. They represent a base of transparent material on which a working layer is applied;
3. Reversible optical discs that allow you to repeatedly record, play back and erase signals (CD-RW; CD-E). These are the most versatile disks, capable of replacing magnetic media in almost all applications. They are similar to write-once discs, but contain a working layer in which the physical writing processes are reversible. The manufacturing technology of such discs is more complex, so they are more expensive than write-once discs.

Currently, optical (laser) disks are the most reliable material carriers of documented information recorded digitally. At the same time, work is actively underway to create even more compact storage media using so-called nanotechnologies that work with atoms and molecules. The packing density of elements assembled from atoms is thousands of times greater than in modern microelectronics. As a result, one CD made using nanotechnology can replace thousands of laser discs.

Electronic storage media

Generally speaking, all the previously discussed media are also indirectly related to electronics. However, there is a type of media where information is stored not on magnetic/optical disks, but in memory chips. These microcircuits are made using FLASH technology, which is why such devices are sometimes called FLASH disks (popularly simply “flash drive”). The microcircuit, as you might guess, is not a disk. However, operating systems define storage media with FLASH memory as a disk (for user convenience), so the name “disk” has a right to exist.

Flash memory is a type of solid-state semiconductor non-volatile rewritable memory. Flash memory can be read as many times as you like, but it can only be written to a limited number of times (usually about 10 thousand times). Despite the fact that there is such a limitation, 10 thousand rewrite cycles is much more than a floppy disk or CD-RW can withstand. Erasing occurs in sections, so you cannot change one bit or byte without overwriting the entire section (this limitation applies to the most popular type of flash memory today - NAND). The advantage of flash memory over regular memory is its non-volatility - when the power is turned off, the contents of the memory are saved. The advantage of flash memory over hard drives, CD-ROMs, and DVDs is the absence of moving parts. Therefore, flash memory is more compact, cheaper (taking into account the cost of read-write devices) and provides faster access.

Data storage

Data storage- is a way of disseminating information in space and time. The method of storing information depends on its medium (book - library, painting - museum, photograph - album). This process is as ancient as the life of human civilization. Already in ancient times, people were faced with the need to store information: notches in trees so as not to get lost while hunting; counting objects using pebbles and knots; depictions of animals and hunting episodes on cave walls.

A computer is designed for compact storage of information with the ability to quickly access it.

Information system is an information repository equipped with procedures for entering, searching, placing and issuing information. The presence of such procedures is the main feature of information systems, distinguishing them from simple accumulations of information materials.

From information to data

People have different approaches to storing information. It all depends on how much it is and how long it needs to be stored. If there is little information, it can be remembered in the mind. It is not difficult to remember your friend's first and last name. And if we need to remember his phone number and home address, we use a notebook. When information is remembered (saved) it is called data.

Data in a computer has different purposes. Some of them are needed only for a short period, others must be stored for a long time. Generally speaking, there are quite a lot of “cunning” devices in a computer that are designed to store information. For example, processor registers, register cache memory, etc. But most “mere mortals” have not even heard such “terrible” words. Therefore, we will limit ourselves to considering random access memory (RAM) and permanent memory, which includes the storage media we have already considered.

Computer RAM

As already mentioned, the computer also has several means for storing information. The fastest way to remember data is to write it into electronic chips. This memory is called RAM. RAM consists of cells. Each cell can store one byte of data.

Each cell has its own address. We can think of this as a cell number, which is why such cells are also called address cells. When a computer sends data to RAM for storage, it remembers the addresses where the data is stored. Referring to the address cell, the computer finds a byte of data in it.

RAM regeneration

The address cell of RAM stores one byte, and since a byte consists of eight bits, there are eight bit cells in it. Each bit cell of a RAM chip stores an electrical charge.

Charges cannot be stored in cells for a long time - they “drain”. In just a few tenths of a second, the charge in the cell is reduced so much that the data is lost.

Disk memory

For permanent storage of data, storage media are used (see section “Types of storage media”). CDs and floppy disks are relatively slow, so most of the information that needs constant access is stored on the hard drive. All information on the disk is stored in the form of files. There is a file system to control access to information. There are several types of file systems.

Disk data structure

In order for data to be not only written to the hard drive, but also read later, you need to know exactly what was written and where. All data must have an address. Each book in the library has its own room, rack, shelf and inventory number - this is like its address. The book can be found at this address. All data that is written to the hard drive must also have an address, otherwise it will not be found.

File systems

It is worth noting that the structure of the data on the disk depends on the type of file system. All file systems consist of structures necessary for storing and managing data. These structures typically include the operating system boot record, directories, and files. The file system also performs three main functions:

1. Tracking occupied and free space
2. Directory and file naming support
3. Tracks the physical location of each file on disk.

Different file systems are used by different operating systems (OS). Some OSes can only recognize one file system, while other OSes can recognize several. Some of the most common file systems are:

• FAT (File Allocation Table)
• FAT32 (File Allocation Table 32)
• NTFS (New Technology File System)
• HPFS (High Performance File System)
• NetWare File System
• Linux Ext2 and Linux Swap

FAT

The FAT file system is used by DOS, Windows 3.x and Windows 95. The FAT file system is also available in Windows 98/Me/NT/2000 and OS/2.

The FAT file system is implemented using File Allocation Table (FAT - File Allocation Tables) and clusters. FAT is the heart of the file system. For security, the FAT is duplicated to protect its data from accidental erasure or malfunction. A cluster is the smallest unit of the FAT system for storing data. One cluster consists of a fixed number of disk sectors. The FAT records which clusters are in use, which are free, and where files are located within the clusters.

FAT-32

FAT32 is a file system that can be used by Windows 95 OEM Service Release 2 (version 4.00.950B), Windows 98, Windows Me and Windows 2000. However, DOS, Windows 3.x, Windows NT 3.51/4.0, earlier versions of Windows 95 and OS/2 do not recognize FAT32 and cannot load or use files on a FAT32 disk or partition.

FAT32 is a development of the FAT file system. It is based on a 32-bit file distribution table, which is faster than the 16-bit tables used by the FAT system. As a result, FAT32 supports much larger disks or partitions (up to 2 TB).

NTFS

NTFS (New Technology File System) is only available on Windows NT/2000. NTFS is not recommended for use on disks smaller than 400 MB because it requires a lot of space for system structures.

The central structure of the NTFS file system is the MFT (Master File Table). NTFS stores multiple copies of the critical portion of the table to protect against problems and data loss.

HPFS

HPFS (High Performance File System) is a privileged file system for OS/2 that is also supported by older versions of Windows NT.

Unlike FAT file systems, HPFS sorts its directories based on file names. HPFS also uses a more efficient structure for directory organization. As a result, file access is often faster and space is used more efficiently than with the FAT file system.

HPFS distributes file data in sectors rather than clusters. To save a track that has sectors or is not in use, HPFS organizes the disk or partition into groups of 8 MB. This grouping improves performance because the read/write heads do not have to return to track zero every time the OS needs to access information about the available space or location of a needed file.

NetWare File System

The Novell NetWare operating system uses the NetWare file system, which was designed specifically for use by NetWare services.

Linux Ext2 and Linux Swap

The Linux Ext2 and Linux file systems were developed for the Linux OS (Free distribution version of UNIX). The Linux Ext2 file system supports a disk or partition with a maximum size of 4 TB.

Directories and file path

Let us consider, as an example, the disk space structure of the FAT system, as the simplest.

The disk space information structure is a user-oriented external representation of disk space and is defined by elements such as volume (logical drive), directory (folder, directory) and file. These elements are used when the user communicates with the operating system. Communication is carried out using commands that perform access operations to files and directories.

Information sources

1. Computer Science: Textbook. – 3rd revision ed. / Ed. N.V. Makarova. – M.: Finance and Statistics, 2002. – 768 p.: ill.
2. Wolf V.K. Study of the functional structure of personal computer memory. Laboratory workshop. Tutorial. Publishing house of Kurgan State University, 2004 – 72 p.

Introduction………………………………………………………………………………………...3

Storage media……………………………………………………………4

Encoding and reading information..……………………………………9

Development prospects…………………….…………………………………….15

Conclusion………………………………………………………………………………….18

Literature…………………………………………………………………………………19

Introduction

In 1945, John von Neumann (1903-1957), an American scientist, came up with the idea of ​​using external storage devices to store programs and data. Neumann developed a block diagram of a computer. All modern computers follow Neumann's scheme.

External memory is designed for long-term storage of programs and data. External memory devices (drives) are non-volatile; turning off the power does not lead to data loss. They can be built into the system unit or made in the form of independent units connected to the system unit through its ports. Based on the method of recording and reading, drives are divided, depending on the type of media, into magnetic, optical and magneto-optical.

Information coding is the process of forming a specific representation of information. A computer can only process information presented in numerical form. All other information (for example, sounds, images, instrument readings, etc.) must be converted into numerical form for processing on a computer. As a rule, all numbers in a computer are represented using zeros and ones (not ten digits, as is usual for people). In other words, computers usually operate in the binary number system, since this makes the devices for processing them much simpler.

Reading information is retrieving information stored in a storage device (memory) and transferring it to other devices of the computer. Reading information is performed during most machine operations, and sometimes is an independent operation.

During the abstract, we will consider the main types of information carriers, encoding and reading information, as well as development prospects.

Information carriers

Historically, the first storage media were punched tape and punched card input/output devices. Following them came external recording devices in the form of magnetic tapes, removable and permanent magnetic disks and magnetic drums.

Magnetic tapes are stored and used wound on reels. There were two types of coils: feeding and receiving. Tapes are supplied to users on feed reels and do not require additional rewinding when installing them in drives. The tape is wound onto a reel with the working layer inward. Magnetic tapes are classified as indirect access storage devices. This means that the search time for any record depends on its location on the media, since a physical record does not have its own address and in order to view it you need to view previous ones. Direct access storage devices include magnetic disks and magnetic drums. Their main feature is that the search time for any record does not depend on its location on the media. Each physical record on the medium has an address that allows direct access to it, bypassing other records. The next type of recording devices were packages of removable magnetic disks, consisting of six aluminum disks. The capacity of the entire package was 7.25 MB.

Let's take a closer look at modern storage media.

1. Floppy magnetic disk drive (FMD – disk drive).

This device uses flexible magnetic disks as a storage medium - floppy disks, which can be 5 or 3 inches. A floppy disk is a magnetic disk, like a record, placed in an “envelope.” Depending on the size of the floppy disk, its capacity in bytes varies. If a standard 5'25" floppy disk can hold up to 720 KB of information, then a 3'5" floppy disk can hold 1.44 MB. Floppy disks are universal, suitable for any computer of the same class equipped with a disk drive, and can be used for storing, accumulating, distributing and processing information. The drive is a parallel access device, so all files are equally easily accessible. The disk is covered on top with a special magnetic layer, which ensures data storage. Information is recorded on both sides of the disk along tracks that are concentric circles. Each track is divided into sectors. The data recording density depends on the density of tracks on the surface, i.e., the number of tracks on the surface of the disk, as well as on the density of information recording along the track. The disadvantages include small capacity, which makes long-term storage of large amounts of information almost impossible, and the not very high reliability of the floppy disks themselves. Currently, floppy disks are practically not used.

2. Hard magnetic disk drive (HDD - hard drive)

It is a logical continuation of the development of magnetic information storage technology. Main advantages:

– large capacity;

– simplicity and reliability of use;

– the ability to access multiple files simultaneously;

– high speed of data access.

The only disadvantage we can highlight is the lack of removable storage media, although external hard drives and backup systems are currently used.

The computer provides the ability, using a special system program, to conditionally split one disk into several. Such disks, which do not exist as a separate physical device, but represent only part of one physical disk, are called logical disks. Logical drives are assigned names using Latin letters [C:], , [E:], etc.

3. Compact disc reader (CD-ROM)

These devices use the principle of reading grooves on a metallized carrier layer of a compact disc with a focused laser beam. This principle makes it possible to achieve a high density of information recording, and, consequently, a large capacity with minimal dimensions. A CD is an excellent means of storing information, it is cheap, practically not subject to any environmental influences, the information recorded on it will not be distorted or erased until the disk is physically destroyed, its capacity is 650 MB. It has only one drawback - the relatively small amount of information storage.

4. DVD

A) Differences between DVD and regular CD-ROM

The most basic difference is, naturally, the amount of information recorded. If you can write 650 MB onto a regular CD (although recently there are discs with 800 MB, but not all drives can read what is written on such a medium), then one DVD will fit from 4.7 to 17 GB. DVD uses a laser with a shorter wavelength, which has significantly increased the recording density, and in addition, DVD implies the possibility of two-layer recording of information, that is, on the surface of the compact there is one layer, on top of which another, translucent one is applied, and the first is read through the second in parallel . There are also more differences in the media themselves than seems at first glance. Due to the fact that the recording density has increased significantly and the wavelength has become shorter, the requirements for the protective layer have also changed - for DVD it is 0.6 mm versus 1.2 mm for regular CDs. Naturally, a disk of such thickness will be much more fragile compared to a classic blank. Therefore, another 0.6 mm is usually filled with plastic on both sides to get the same 1.2 mm. But the main bonus of such a protective layer is that, thanks to its small size, it became possible to record information on both sides on one compact, that is, to double its capacity, while leaving the dimensions almost the same.

B) DVD capacity

There are five types of DVDs:

1. DVD5 – single-layer, single-sided disc, 4.7 GB, or two hours of video;

2. DVD9 – double-layer single-sided disc, 8.5 GB, or four hours of video;

3. DVD10 – single-layer double-sided disc, 9.4 GB, or 4.5 hours of video;

4. DVD14 – double-sided disc, two layers on one side and one on the other side, 13.24 GB, or 6.5 hours of video;

5. DVD18 – double-layer, double-sided disc, 17 GB, or more than eight hours of video.

The most popular standards are DVD5 and DVD9.

IN) Possibilities

The situation with DVD media now resembles that of CDs, which for a long time also only stored music. Now you can find not only films, but also music (so-called DVD-Audio) and software collections, games, and films. Naturally, the main area of ​​use is film production.

G) Sound in DVD

Audio can be encoded in many formats. The most famous and frequently used are Dolby Prologic, DTS and Dolby Digital of all versions. That is, in fact, in the formats used in cinemas to obtain the most accurate and colorful sound picture.

D) Mechanical damage

CD and DVD discs are equally sensitive to mechanical damage. That is, a scratch is a scratch. However, due to the much higher recording density, the losses on the DVD disc will be more significant. Now there are programs that can recover information even from damaged disks, although they skip damaged sectors.

The rapidly growing market for portable hard drives designed to transport large amounts of data has attracted the attention of one of the largest hard drive manufacturers. Western Digital has announced the release of two device models called WD Passport Portable Drive. Options with a capacity of 40 and 80 GB are on sale. WD Passport Portable Drives are based on 2.5-inch WD Scorpio EIDE HDDs. They are packaged in a rugged case, equipped with support for Data Lifeguard technology, and do not require an additional power source (powered via USB). The manufacturer notes that the drives do not heat up, operate quietly and consume little energy.

6.USB Flash Drive

A new type of external storage medium for a computer, which appeared due to the widespread use of the USB (universal bus) interface and the advantages of Flash memory chips. A sufficiently large capacity with a small size, energy independence, high speed of information transfer, protection from mechanical and electromagnetic influences, the ability to be used on any computer - all this allowed the USB Flash Drive to replace or successfully compete with all previously existing storage media.

Encoding and reading information

A modern computer can process numerical, text, graphic, sound and video information. All these types of information in a computer are presented in binary code, that is, an alphabet of power two is used (only two characters 0 and 1). This is due to the fact that it is convenient to represent information in the form of a sequence of electrical impulses: there is no impulse (0), there is an impulse (1). Such coding is usually called binary, and the logical sequences of zeros and ones themselves are called machine language.

Each digit of machine binary code carries an amount of information equal to one bit. This conclusion can be made by considering the numbers of the machine alphabet as equally probable events. When writing a binary digit, you can choose only one of two possible states, which means it carries an amount of information equal to 1 bit. Therefore, two digits carry 2 bits of information, four digits carry 4 bits, etc. To determine the amount of information in bits, it is enough to determine the number of digits in binary machine code.

A) Encoding text information

Currently, most users use a computer to process text information, which consists of symbols: letters, numbers, punctuation marks, etc. Traditionally, in order to encode one character, an amount of information equal to 1 byte is used, i.e. I = 1 byte = 8 bit. Using a formula that connects the number of possible events K and the amount of information I, you can calculate how many different symbols can be encoded (assuming that symbols are possible events): K = 2I = 28 = 256, i.e. to represent text information, you can use an alphabet with a capacity of 256 characters. The essence of coding is that each character is assigned a binary code from 00000000 to 11111111 or a corresponding decimal code from 0 to 255. It must be remembered that at present

Binary code	Decimal code	KOI8	CP1251	CP866	Mas	ISO
11000010	194	b	IN	-	-	T

time, five different codes are used to encode Russian letters

tables (KOI - 8, CP1251, CP866, Mac, ISO), and texts encoded using one table will not be displayed correctly in another encoding. This can be visually represented as a fragment of a combined character encoding table. Different symbols are assigned to the same binary code. However, in most cases, the user takes care of transcoding text documents, and special programs are converters that are built into applications.

B) Encoding graphic information

In the mid-50s, for the first time, data representation was implemented in graphical form for large computers that were used in scientific and military research. Without computer graphics, it is difficult to imagine not only a computer, but also a completely material world, since data visualization is used in many areas of human activity. Graphic information can be presented in two forms: analog or discrete. A painting whose color changes continuously is an example of an analog representation, while an image printed using an inkjet printer and consisting of individual dots of different colors is a discrete representation. By splitting a graphic image (sampling), graphic information is converted from analogue form to discrete form. In this case, coding is performed - assigning a specific value to each element in the form of a code. When encoding an image, it is spatially discretized. It can be compared to constructing an image from a large number of small colored fragments (mosaic method). The entire image is divided into separate points, each element is assigned a color code. In this case, the quality of encoding will depend on the following parameters: dot size and the number of colors used. The smaller the dot size, which means the image is made up of a larger number of dots, the higher the encoding quality. The more colors are used (i.e., an image point can take on more possible states), the more information each point carries, and, therefore, the encoding quality increases. Creation and storage of graphic objects is possible in several types - in the form of a vector, fractal or raster image. A separate subject is 3D (three-dimensional) graphics, which combines vector and raster methods of image formation. She studies methods and techniques for constructing three-dimensional models of objects in virtual space. Each type uses its own method of encoding graphic information.

IN) Encoding of audio information

Since childhood, we have been exposed to recordings of music on different media: records, cassettes, CDs, etc. Currently, there are two main ways to record sound: analog and digital. But in order to record sound on any medium, it must be converted into an electrical signal. This is done using a microphone. The simplest microphones have a membrane that vibrates under the influence of sound waves. A coil is attached to the membrane, moving synchronously with the membrane in a magnetic field. An alternating electric current occurs in the coil. Voltage changes accurately reflect sound waves. The alternating electric current that appears at the output of the microphone is called analog signal. When applied to an electrical signal, “analog” means that the signal is continuous in time and amplitude. It accurately reflects the shape of the sound wave as it travels through the air. Audio information can be represented in discrete or analog form. Their difference is that with a discrete representation of information, a physical quantity changes abruptly (“ladder”), taking on a finite set of values. If information is presented in analog form, then a physical quantity can take on an infinite number of values ​​that are continuously changing. A vinyl record is an example of analog storage of sound information, since the sound track changes its shape continuously. But analog recordings on magnetic tape have a big drawback - the aging of the medium. Over the course of a year, a phonogram that had a normal level of high frequencies may lose them. Vinyl records lose quality several times when played. Therefore, preference is given to digital recording. In the early 80s, compact discs appeared. They are an example of discrete storage of audio information, since the audio track of a CD contains areas of varying reflectivity. In theory, these digital discs can last forever if they are not scratched, i.e. their advantages are durability and resistance to mechanical aging. Another advantage is that there is no loss of sound quality when dubbing digitally. On multimedia sound cards you can find an analog microphone preamp and mixer. Let's consider the processes of converting sound from analogue to digital form and vice versa. Having a rough idea of ​​what's going on in your sound card can help you avoid some mistakes when working with audio. Sound waves are converted into an analog alternating electrical signal using a microphone. It passes through the audio path and enters an analog-to-digital converter (ADC), a device that converts the signal into digital form. In a simplified form, the operating principle of an ADC is as follows: it measures the signal amplitude at certain intervals and transmits further, via a digital path, a sequence of numbers carrying information about changes in amplitude. During analog-to-digital conversion, no physical conversion occurs. It is as if a fingerprint or sample is taken from the electrical signal, which is a digital model of voltage fluctuations in the audio path. If this is depicted in the form of a diagram, then this model is presented as a sequence of columns, each of which corresponds to a specific numerical value. A digital signal is by its nature discrete - that is, intermittent - so the digital model does not exactly match the shape of the analog signal. Digital audio is output using a digital-to-analog converter (DAC), which, based on incoming digital data, generates an electrical signal of the required amplitude at appropriate times.

Reading information is retrieving information stored in a storage device (memory) and transferring it to other devices of the computer. Reading information is performed during most machine operations, and sometimes is an independent operation. Reading may be accompanied by the destruction (erasure) of information in those cells (zones) of the memory from which the reading was made (as, for example, in memory on ferrite cores), or it can be non-destructive (for example, in memory on magnetic tapes, disks) and, therefore, allowing reuse of once recorded information. Reading information is characterized by the time spent directly on outputting data from the memory; it ranges from several tens of nanoseconds to several milliseconds.

Let's consider the process of reading information using the example of a CD. Data from the disk is read using a laser beam with a wavelength of 780 nm. The principle of reading information with a laser for all types of media is to register changes in the intensity of reflected light. The laser beam is focused on the information layer into a spot with a diameter of ~1.2 μm. If the light is focused between the pits (on the landing), then the photodiode registers the maximum signal. If light hits the pit, the photodiode registers a lower light intensity. The difference between read-only disks and write-once/write-once disks lies in the way the pits are formed. In the case of a read-only disk, the pits are a kind of relief structure (phase diffraction grating), with the optical depth of each pit being slightly less than a quarter of the wavelength of the laser light, which leads to a phase difference of half a wavelength between the light reflected from the pit and the light , reflected from the land. As a result, a destructive interference effect is observed in the plane of the photodetector and a decrease in the signal level is recorded. In the case of CD-R/RW, the pit is an area with greater light absorption than the land (amplitude diffraction grating). As a result, the photodiode also detects a decrease in the intensity of light reflected from the disk. The length of the pit changes both the amplitude and duration of the recorded signal.

The CD read/write speed is indicated as a multiple of 150 KB/s (that is, 153,600 bytes/s). For example, a 48-speed drive provides a maximum CD read (or write) speed of 48 × 150 = 7200 KB/s (7.03 MB/s).

Development prospects

The development of recording media is proceeding in 3 main directions:

a) increasing the amount of useful information on a specific medium (especially important for optical disks);

b) improving the quality of technical equipment (access time to information, data transfer speed);

c) a gradual increase in the level of compatibility of various media formats used.

Promising types of memory media include: Eye-Fi, Holographic Versatile Disc, Millipede.

Eye-Fi- a type of SD flash memory card with hardware elements supporting Wi-Fi technology built into the card.

The cards can be used in any digital camera. The card is inserted into the corresponding slot of the camera, receiving power from the camera and at the same time expanding its functionality. A camera equipped with such a card can transfer captured photographs or videos to a computer, to the Internet to pre-programmed resources that carry out photo or video hosting of this kind of content. Administration, access to settings and control of the operation of such cards is carried out via Wi-Fi from a PC or Mac compatible computer through a browser. The card only works through pre-registered Wi-Fi networks; WEP and WPA2 encryption is supported.

Specifications:

Card capacity: 2, 4 or 8 GB

Supported Wi-Fi standards: 802.11b, 802.11g

Wi-Fi Security: Static WEP 64/128, WPA-PSK, WPA2-PSK

Card dimensions: SD standard - 32 x 24 x 2.1 mm

Card weight: 2.835 g

Holographic multi-purpose disk (Holographic Versatile Disc)- a promising technology for the production of optical discs is being developed, which involves significantly increasing the amount of data stored on the disc compared to Blu-Ray and HD DVD. It uses a technology known as holography, which uses two lasers, one red and one green, combined into one parallel beam. The green laser reads data encoded in a grid from a holographic layer close to the surface of the disc, while the red laser is used to read auxiliary signals from a regular CD layer deep inside the disc. The auxiliary information is used to track the read position, similar to the CHS system in a regular hard drive. On a CD or DVD, this information is embedded in the data. The estimated storage capacity of these discs is up to 3.9 terabytes (TB), which is comparable to 6000 CDs, 830 DVDs or 160 single-layer Blu-ray discs; data transfer speed - 1 Gbit/sec. Optware was going to release a 200GB drive in early June 2006 and Maxell in September 2006 with a 300GB capacity. On June 28, 2007, the HVD standard was approved and published.

Holographic Disc (HVD) structure

1. Green laser read/write (532nm)

2. Red positioning/indexing laser (650nm)

3. Hologram (data)

4. Polycarbonate layer

5. Photopolymeric layer (layer containing data)

6. Distance layers

7. Dichroic layer

8. Aluminum reflective layer (red light reflective)

9. Transparent base

P. Recesses

Millipede is a relatively new storage technology being developed by IBM. A scanning probe microscope probe is used to read and record information. Scientists from the University of Science and Technology in Pohang (South Korea) are also working on issues of Millipede memory. They were the first in the world to create a material suitable for creating millilipid memory. The peculiarity of millilipid memory is that information is stored in a huge number of nanopits covering the surface of the working material. Moreover, such memory is non-volatile, and data is stored in it for as long as desired. To create a working prototype of millilipid memory, Korean electronics engineers have developed a unique polymer material. Only with its help was it possible to create a stably functioning storage device, which is almost ready for implementation in production.

Conclusion

During the abstract, the main types of information carriers, principles of encoding and reading information, as well as prospects for the development of information carriers were considered.

The history of information media (punched tapes, punched cards, magnetic tapes, removable and permanent magnetic disks, magnetic drums, packages of removable magnetic disks) was also considered; floppy drives, hard drives, CDs, DVDs, portable USB drives, USB Flash Drive. Coding (text, graphic, sound) and reading information (using the example of reading information from a CD) were considered. The most promising today are Eye-Fi, Holographic Versatile Disc and Millipede.

1) Paper media.

One of the most common storage media is paper. At school, we write down information in notebooks, study theoretical material from textbooks, when developing a report, abstract or other message, we find the necessary information in other sources (books, encyclopedias, dictionaries, etc.) (Fig. 5), which in turn

queue are paper media

The first computers ran on punch cards.(Fig.6, Fig.7)

Magnetic tape turned out to be a fairly reliable, durable and accessible storage medium for everyone.

In the first computers (electronic computers), information was stored on magnetic tapes and magnetic disks (slide 17 - the first computer)

(The teacher’s explanation is accompanied by a demonstration of magnetic disks.

One floppy disk is distributed to each desk for students to “study” it)

Modern computers use the following magnetic media as information storage media:

1) diskette(on which the data of 3000 punched cards can be placed).

2) hard magnetic disk or Winchester ( stores 100,000 or more floppy disks). Inside the rigid metal case there are several dozen magnetic disks located on the same axis (Fig. 12). Writing or reading information is provided by several magnetic heads. In order to preserve information and performance, hard magnetic drives must be protected from

shocks and sudden changes in the position of the system unit (you cannot

Tilt and turn over while working).

3) streamers(stream cartridges) - devices that provide recording or reading of audio information (Fig. 13). Inside this media there is a magnetic tape.

Laser discs are made of plastic, covered with a thin layer of metal and a transparent varnish that protects from minor scratches or dirt. Information is written to or read from a CD drive using laser light. When recording, a laser beam burns microscopic depressions on the surface of the disk, thereby encoding information (when reading, the laser beam is reflected from the surface of the rotating disk). Such discs should be protected from dust and scratches.

There are CDs and DVDs.

Questions: - What information can be burned onto CDs and DVDs?(DVD is called a digital video disc, therefore, video and audio information can be recorded on it; text, graphic, and audio information can be recorded on a CD).

According to the recording method, laser discs are divided into the following types:

· CD- ROM, DVD- ROM- are read-only. You cannot write or delete information from such a disk. Such discs include educational, game programs, electronic textbooks, etc.

· CD- R, DVD- R- You can write information to disk only once. Once recorded, the data cannot be deleted.

· CD- RW, DVD- RW- You can write information to such a disk several times.

Man has always strived not only to learn as much as possible about the world around him, but also to pass on all the accumulated information to future generations. In this article we will consider, albeit briefly, the development of methods for storing and transmitting information, the evolution of information media, starting from a stone wall in a cave and ending with the latest developments in the field of high technology.

Legends of deep antiquity...

Soon, with the advent of the first civilizations, pictography was transformed into hieroglyphs and cuneiform. Abstract concepts, calculus, etc. have already appeared in the new sign system. And the sign system itself has become smaller in size.

The media also changed: now stone walls have become man-made, stone carving has become more skillful. Compact storage media also appeared: papyrus sheets in Egypt and clay tablets in Mesopotamia.

The closer to our days, the cheaper and more compact the storage media became, the volume of information increased by orders of magnitude, and the linguistic sign system became increasingly simpler.

From papyrus, humanity moved to parchment, from parchment to paper. From hieroglyphics to alphabetic writing (even today's hieroglyphic languages ​​- Chinese, Japanese, Korean - are based on a standard alphabetic set).

So, in a few paragraphs, we looked at the past of language and information carriers and, practically, came close to the main topic.

Evolution of information carriers in the XX-XXI centuries

Punched cards and paper tapes

With the development of mechanical engineering and production automation, it became necessary to program machine tools and machines - specifying a sequential set of operations to streamline production. For this purpose, a binary language was created (0/1 - off/on), and the first carrier of information in a binary language was a punched card. A sheet of thick paper was divided into a certain number of cells, some of them were pierced, others remained intact. A standard punched card carried 80 characters of information.

Later, using the same principle of operation, punched paper tape began to be used - a roll of paper or nitrocellulose tape with punched holes. The advantage of punched tape was the relatively high reading speed (up to 1500 B/sec), but the low strength of the tape and the impossibility of manual editing of information (for example, a punched card could be pulled out of the deck and manually punched the necessary bits).

Magnetic tape

Paper media has been replaced by magnetic media. At first it was a specially magnetized wire (such a medium is still used in aircraft black boxes), then it was replaced by flexible magnetic tape, which was wound into reels or compact cassettes. The principle of recording is somewhat similar to punching. The magnetic tape is divided across its width into several independent tracks; passing through the magnetic recording head, the required section of the tape is magnetized (similar to the punched section of the punched tape); subsequently, the magnetized section will be read by computer technology as 1, and the non-magnetized section as 0.

Floppy magnetic disks

Following the magnetic tape, a flexible magnetic disk was invented - a circle made of dense flexible plastic with a magnetic layer applied to the surface. The first floppy disks were eight-inch, later they were replaced by the more familiar 5.25-inch and 3.5-inch ones. The latter lasted in the storage media market until the mid-2000s.

Drives on tough magnetic disks

In parallel with flexible magnetic media, media on hard magnetic disks (HDD, hard drive, HDD) developed. The first working HDD model was created in 1956 by IBM (model IBM 350). The capacity of the IBM 350 was 3.5 MB, which was quite a lot at that time. The first HDD was the size of a large refrigerator and weighed just under a ton.

Over thirty years, the size of the hard drive was reduced to a 5.25-inch format (the size of an optical drive); ten years later, hard drives became the familiar 3.5-inch format.

The 1 GB capacity was surpassed in the mid-1990s, and in 2005 the maximum capacity for longitudinal recording was reached - 500 GB. In 2006, the first hard drive with a perpendicular recording method was released with a capacity of 500 GB. In 2007, the 1 TB milestone was passed (the model was released by Hitachi). At the moment, the largest volume of a commercial HDD model is 3 TB.

Flash memory is a type of semiconductor electrically reprogrammable memory (EEPROM) technology. Due to its compactness, low cost, mechanical strength, large capacity, speed and low power consumption, flash memory is widely used in digital portable devices and storage media.

There are two main types of flash memory: NOR And NAND.

NOR memory is used as small-volume non-volatile memory that requires fast access without hardware failures (microprocessor cache, POST and BIOS chips).

NAND memory is used in most electronic devices as the main storage medium (cell phones, TVs, media players, game consoles, photo frames, navigators, network routers, access points, etc.). NAND memory is also used in SSD drives, an alternative to magnetic hard drives, and as cache memory in hybrid hard drives. Also, don’t forget about flash cards of all form factors and connection types.

The most significant disadvantage of flash memory is the limited number of write cycles to the media. This is due to the technology of reprogrammable memory itself.

Optical discs

These media are polycarbonate disks with a special metal coating applied to one side. Recording and subsequent reading is carried out using a special laser. During recording on a metal coating, the laser makes special pits (pits), which, when subsequently read by a laser disk drive, will be read as “1”.

The entire development of optical media can be divided into four parts:

First generation: laser discs, compact discs, magneto-optical discs. The main feature is that relatively expensive disks of small volume; the drives have high energy consumption (directly related to the technology of writing and reading disks). Compact discs are a little out of this definition (which is probably why they took a dominant position before the advent of the second generation of optical discs).

Second generation: DVD, MiniDisc, Digital Multilayer Disk, DataPlay, Fluorescent Multilayer Disc, GD-ROM, Universal Media Disc. What makes the second generation of optical disks different from the first? First of all, high density of information recording (6-10 times). In addition to DVDs, they mainly have specialized applications (MD - for audio recordings, UMD - for Sony PlayStation consoles). Apart from DVD, all other formats require expensive hardware to write and read information (especially DMD and FMD, which use multi-layer and multi-dimensional storage technologies).

Third generation: Blu-ray Disc, HD DVD, Forward Versatile Disc, Ultra Density Optical, Professional Disc for DATA, Versatile Multilayer Disc. These optical discs are necessary for storing high-definition video. The main feature is the use of a blue=violet laser to write and read information in place of the red one (except VMD). This allows you to further increase the recording density (6-10 times compared to the second generation).

As in any evolution, in the development of optical disks there is a main branch of development and side branches. The main branch consists of the types of optical discs that are most widespread and have the greatest commercial success: CDs, DVDs, Blu-Rays. The remaining types of optical disks have either reached a dead end in their development or have specialized applications.

Fourth generation (near future): Holographic Versatile Disc. The main revolutionary technology in the development of optical storage media is considered to be holographic recording technology, which makes it possible to increase the recording density on an optical disk by approximately 60-80 times. The first holographic disks were introduced back in 2006, and the technology standard itself was finally approved in 2007. But things are still there. In 2010, it was announced that the storage capacity limit of 515 GB had been exceeded, but this model of the holographic disk was not put into production.