Carriers are found. Types of storage media. Information storage. External hard drives

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In the era of high technology, data storage and access to it is one of the important human factors. For the average user, important data is his home photos and videos, especially photographs and footage of significant dates, but his favorite collections of music and films also play an important role. For people whose computer is not only an entertainment center, but also helps in everyday work, electronic office files are important data, which help eliminate paperwork.

We often forget about what and how is stored on the computer, since the workflow is completely automated. But unfortunately, sources of electronic information storage are far from ideal and usually fail at the most inopportune moment for us.

So what are modern storage media? Probably almost every computer user uses hard drive, as the main storage of data files. This is a high-tech device, which is a small iron box, completely sealed, containing a magnetic disk several millimeters thick. Usually, an electronic head floats below or above at a micron distance from the disk, reading information. The disk rotation speed is about 10,000 rpm. Any microscopic speck of dust that lands on the surface of a magnetic disk will almost immediately cause failure of the entire “hard drive” (another name for a hard drive). And this is just one of the few reasons that can cause the rapid death of this digital medium. In fact, a hard drive failure can cause even a simple power surge.

The very first storage medium that everyone remembers was the laser compact disc. Then we looked at this brilliant “ round” and puzzled over how a collection of our favorite music was recorded on it. By the way, for certain reasons, this medium still does not lose its relevance. First of all, probably because of their small size and conditional price - now in any store there are empty “blanks” “ CD" or " DVD"for the record, you can buy it almost free of charge. Another reason for the survivability of these media lies in their convenient use for creating information products by companies developing software for one or another electronic device, such as a printer, scanner, digital camera, and the like. Or use CDs to create your own music and films. It is very convenient to capture your “masterpieces” in the form of electronic files recorded on a laser disc placed in a beautiful box, with a detailed indication of the disc menu and other features. Moreover, the costs of such packaging are scanty.

A laser disk consists of several layers connected together: the first, bottom one is made of polycarbonate, the second is made of thin aluminum, on which information is stored, the third is a protective layer, a regular varnish coating with a label. This is the standard structure " CD"disk, " DVD"consists of similar layers, only there are usually many more of them, and they are better protected. That is why it is preferable to store information on " DVD» disks than on « CD" In addition, the volume of the latter is 6-7 times less.

The most common carrier, or even more precisely, a “storage” of information, at the moment is the well-known “flash drive”. " USB FlashDrive“consists of electronic chips capable of holding charges (electrons), which contain information. This is the most convenient media for the average user, since its dimensions are minimal. A flash drive is used in almost all modern devices, even such as TVs and radios. The main disadvantage of this drive is its short life. You can write information to it about 10,000 times, then this device usually no longer works or malfunctions.

Along with flash drives, in terms of frequency of use, there are also external media, small boxes that connect to the port " USB» computers and have a capacity from 80 to 1000 gigabytes and above. Many people think that these are the same flash drives, only with a larger capacity. But if we open such a device, we will see inside a regular laptop hard drive, which is connected to our computer through a kind of “bridge”. In essence, this is the same hard drive, and since its dimensions are miniature to fit freely into a laptop, the system is more susceptible to risk than the hard drive of a personal computer.

Recently, solid-state hard drives have appeared on the computer accessories market. The data reading speed of such devices is several times higher than that of a regular computer hard drive. It is because of their speed that they have become so widespread. But such disks are not cheap, and are unlikely to be suitable for the average person who is very limited on a budget when building their own computer. And such devices also have many disadvantages. Since they consist of the same microcircuits as those on a “USB flash drive,” their life expectancy is short. Although we must admit that the future still lies with these small devices, they still need to be refined for more than one year.

So which drive should the average user choose to store their home photos or a collection of music and movies? It’s difficult to answer right away. Let's consider the life expectancy of the above-mentioned storage media.

Computer hard drive. On the one hand, the device is quite reliable. It works quickly, and it has an unlimited number of rewrite cycles, it all depends on the quality of the magnetic disk. But if there is a small power surge, an accidental shock (especially when the computer is on), or other unexpected events, " Winchester"can fail instantly.

Laser CD, “blanks” (blanks, empty “ CD" or " DVD") is the cheapest and fairly reliable option for storing collections of home photos and videos. They cost no more than 20 rubles in any specialized store. Of course we forgot the two-layer " DVD discs”, which have twice the capacity of regular CDs. In addition, laser discs have been on the market for about two years now.” Blue-Ray", the volume of which is about 25 gigabytes, which is five times larger than the standard " DVD" But the price of such media is many times higher, and besides, in order to record on “blue-ray” (translated from English as blue ray), you will need a special drive, the price of which is also far beyond the allowed budget of the common man.

And yet, for quickly creating backup copies of your favorite files, CDs are recommended. Only after burning (recording) should they be stored in a dark, dry place where rays of sunlight, the main enemy of laser media, do not pass through. It is also necessary to take into account that the warranty period for storing recorded information on CDs is about six years. At the end of this period, it is better to rewrite the information to another " blank».

What can you say about the reliability of the previously mentioned and well-known flash drive? Despite its small size and ease of use, reliable storage is out of the question. Information can be lost even when it is removed from a computer or other device. These media also fail very often, especially if our Chinese friends took part in its creation.

Solid State Drives (SSDs) are also very questionable storage sources. Of course, their production is much more technologically advanced than the production of “flash drives”, but the principle of operation is the same and the disadvantages are the same. Although if you buy such media, write down your favorite photos on it and put it in a closet without touching it again, it will last a long time. But who will allow themselves such luxury?

Currently, quite a lot of well-known Internet resources have appeared on the Internet, such as “ Yandex" And " Google”, which offer to use their disk space absolutely free of charge. Such companies are very reliable and in case of failure, information is restored from backup copies. Typically, such sites provide you with a mailbox upon registration, and as a bonus you get disk space, the size of which starts from 10 gigabytes.

Let's summarize. What media are the best for the user? For a number of the above-mentioned reasons, the conventional laser disc becomes the leader. If we also take into account “non-domestic” storage sources, then, of course, Internet resources will become the undisputed leader, since the percentage of data loss on them is much lower. In general, following the advice of experienced computer scientists, you need to duplicate important information on different media more often, thus reducing the risk of loss to zero.

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.

Information 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.

disk file drive information

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 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)

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.

Storage media – material that is intended for recording, storage and subsequent reproduction of information.

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

Storage medium is the physical environment in which it is recorded.

The media can be paper, photographic film, brain cells, punched cards, punched tapes, magnetic tapes and disks or computer memory cells. Modern technology offers more and more new types of storage media. They use the electrical, magnetic and optical properties of materials to encode information. Media are being developed in which information is recorded even at the level of individual molecules.

In modern society, three main types of information media can be distinguished:

1) Perforated - have a paper base, information is entered in the form of punches in the corresponding row and column. The volume of information is 800 bits or 100 KB;

2) Magnetic – they use flexible magnetic disks and cassette magnetic tapes;

3) optical.

Information carriers include:

Magnetic disks;

- magnetic drums- an early type of computer memory, widely used in the 1950-1960s. Invented by Gustav Tauschek in 1932 in Austria. Later, the magnetic drum was replaced by memory on magnetic cores.

- floppy disks- a portable magnetic storage medium used for repeated recording and storage of relatively small data. Writing and reading is carried out using a special device - a disk drive;

- magnetic tapes- a magnetic recording medium, which is a thin flexible tape consisting of a base and a magnetic working layer;

- optical discs- an information carrier 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, but is now widely used as a general-purpose storage device;

- flash memory- 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). Erasing occurs in sections, so you cannot change one bit or byte without overwriting the entire section.

All media can be divided into:

1. Human readable (documents).

2. Machine-readable (machine) - for intermediate storage of information (disks).

3. Human-machine-readable – combined media for highly specialized purposes (forms with magnetic stripes).

However, the rapid development of computer technology has erased the line between the 1st and 3rd groups - a scanner has appeared that allows you to enter information from documents into the computer memory.

All currently available storage media can be divided according to various criteria. First of all, it is necessary to distinguish volatile And non-volatile information storage devices.

Non-volatile drives used for archiving and saving data arrays are divided into:

1. by type of record:

– magnetic storage devices (hard disk, floppy disk, removable disk);

– magnetic-optical systems, also called MO;

– optical, such as CD (Compact Disk, Read Only Memory) or DVD (Digital Versatile Disk);

2. by construction methods:

– a rotating platter or disk (as in a hard disk, floppy disk, removable disk, CD, DVD, or MO);

– tape media of various formats;

– drives without moving parts (for example, Flash Card, RAM (Random Access Memory), which have a limited scope due to relatively small amounts of memory compared to the above).

If quick access to information is required, such as when outputting or transmitting data, then media with a rotating disk are used. For archiving performed periodically (Backup), on the contrary, tape media are more preferable. They have large amounts of memory combined with a low price, although at relatively low performance.

Based on their purpose, storage media are divided into three groups:

1. dissemination of information: Pre-recorded media such as CD ROM or DVD-ROM;

2. archiving: media for one-time recording of information, such as CD-R or DVD-R (R (record able) - for recording);

3. backup or data transfer: media with the ability to record information reusably, such as floppy disks, hard disks, MO, CD-RW (RW (rewritable) - rewritable and tapes.

The need for humans to store any information appeared in prehistoric times, a striking example of which is rock painting, which has survived to this day. Rock paintings can rightly be called the most durable storage medium at the moment, although there are some difficulties with portability and ease of use. With the advent of computers (and PCs in particular), the development of capacious and easy-to-use storage media has become especially important.

Paper media

The first computers used punched cards and perforated paper tape wound on reels, called punched tape. Its ancestors were automated looms, in particular the Jacquard machine, the final version of which was created by the inventor (after whom it is named) in 1808. To automate the thread feeding process, perforated plates were used:

Punch cards were cardboard cards that used a similar method. There were many varieties of them, both with holes that corresponded to “1” in binary code, and text type. The most common was the IBM format: the card size was 187x83 mm, the information on it was located in 12 lines and 80 columns. In modern terms, one punched card stored 120 bytes of information. To enter information, punched cards had to be fed in a certain sequence.

Punched paper tape uses the same principle. Information is stored on it in the form of holes. The first computers created in the 40s of the last century worked both with data entered using punched tape in real time and used some kind of random access memory, mainly using cathode ray tubes. Paper media were actively used in the 20-50s, after which they gradually began to be replaced by magnetic media.

Magnetic media

In the 50s, the active development of magnetic media began. The basis was the phenomenon of electromagnetism (the formation of a magnetic field in a conductor when current is passed through it). The magnetic medium consists of a surface coated with a ferromagnet and a read/write head (a core with a winding). Current flows through the winding, and a magnetic field of a certain polarity appears (depending on the direction of the current). A magnetic field acts on a ferromagnet and the magnetic particles in it are polarized in the direction of the field and create residual magnetization. To record data, different areas are exposed to a magnetic field of different polarity, and when reading data, zones are recorded in which the direction of the remanent magnetization of the ferromagnet changes. The first such media were magnetic drums: large metal cylinders coated with a ferromagnet. Reading heads were installed around them.

After them, the hard drive appeared in 1956, it was IBM's 305 RAMAC, which consisted of 50 disks with a diameter of 60 cm, was comparable in size to a large modern Side-by-Side refrigerator and weighed just under a ton. Its volume was an incredible 5 MB at that time. The head moved freely along the surface of the disk and the operating speed was higher than that of magnetic drums. The process of loading the 305 RAMAC into an aircraft:

The volume quickly began to increase and in the late 60s IBM released a high-speed drive with two 30 MB disks. Manufacturers actively worked to reduce dimensions and by 1980 the hard drive had the dimensions of a 5.25-inch drive. Since then, the design, technology, volume, density and dimensions have undergone enormous changes and the most popular form factors have become 3.5, 2.5 inches, and to a lesser extent 1.8 inches, and volumes have already reached tens of terabytes on one media.

For some time, the IBM Microdrive format was also used, which was a miniature hard drive in the form factor of a CompactFlash memory card. type II. Released in 2003, later sold to Hitachi.

At the same time, magnetic tape was developing. It appeared along with the release of the first American commercial computer, UNIVAC I, in 1951. Again, IBM tried. Magnetic tape was a thin plastic strip with a magnetically sensitive coating. Since then it has been used in a variety of form factors.

From reels, tape cartridges to compact cassettes and VHS video cassettes. They were used in computers from the 70s to the 90s (already in much smaller quantities). Often, a connected tape recorder was used as an external media for the PC.

Magnetic tape drives called streamers are still used today, mainly in industry and big business. Currently standard reels are used Linear Tape-Open (LTO), and the record was set this yearIBM and FujiFilm managed to record 154 terabytes of information onto a standard reel. The previous record was 2.5 terabytes, LTO 2012.

Another type of magnetic media is floppy disk or floppy disk. Here, a layer of ferromagnetic material is applied to a flexible, lightweight base and placed in a plastic case. Such media were simple to manufacture and had a low cost. The first floppy disk had an 8-inch form factor and appeared in the late 60s. The creator is again IBM. By 1975, the capacity reached 1 MB. Although floppy disks gained popularity thanks to people from IBM who founded their own company Shugart Associates and in 1976 released a 5.25-inch floppy disk with a capacity of 110 KB. By 1984, the capacity was already 1.2 MB, and Sony came up with a more compact 3.5-inch form factor. Such floppy disks can still be found in many homes.

Iomega released 10 and 20 MB Bernoulli Box magnetic disk cartridges in the 1980s, and in 1994 the so-calledZip 3.5 inches in size with a capacity of 100 MB, they were quite actively used until the end of the 90s, but they were too tough to compete with CDs.

Optical media

Optical media are disk-shaped and read from them using optical radiation, usually a laser. The laser beam is directed at a special layer and reflected from it. When reflected, the beam is modulated by tiny notches on a special layer; when these changes are registered and decoded, the information recorded on the disk is restored. Optical recording technology using a light-transmitting medium was first developed by David Paul Gregg in 1958 and patented in 1961 and 1990, and in 1969 Philips created the so-called LaserDisc, in which light was reflected. LaserDisc was first shown to the public in 1972, and went on sale in 1978. It was close in size to vinyl records and was intended for films.

In the seventies, the development of a new type of optical media began, as a result of which Philips and Sony introduced the CD (Compact Disk) format in 1980, which was first demonstrated in 1980. CDs and equipment went on sale in 1982. Originally used for audio, it lasted up to 74 minutes. In 1984, Philips and Sony created the CD-ROM (Compact Disc Read Only Memory) standard for any type of data. The disk capacity was 650 MB, later - 700 MB. The first discs that could be recorded at home, rather than at the factory, were released in 1988 and were called CD-R (Compact Disc Recordable), and CD-RW, which allows multiple rewriting of data on a disk, appeared already in 1997.

The form factor did not change, the recording density increased. In 1996, the DVD (Digital Versatile Disc) format appeared, which had the same shape and diameter of 12 cm, and the volume was 4.7 GB or 8.5 GB for a double-layer one. To work with DVDs, corresponding drives have been released that are backward compatible with CDs. Several more DVD standards were released in subsequent years.

In 2002, two different and incompatible new generation optical disc formats were introduced to the world: HD DVD and Blu-ray Disc (BD). In both cases, a blue laser with a wavelength of 405 nm is used to write and read data, which makes it possible to further increase the density. HD DVD is capable of storing 15 GB, 30 GB or 45 GB (one, two or three layers), Blu-ray - 25, 50, 100 and 128 GB. The latter became more popular and in 2008 Toshiba (one of the creators) abandoned HD DVD.

Semiconductor media

In 1984, Toshiba introduced semiconductor media called NAND flash memory, which became popular a decade after its invention. The second variant of NOR was proposed by Intel in 1988 and is used to store software codes such as the BIOS. NAND memory is now used in memory cards, flash drives, SSD drives and hybrid hard drives.

NAND technology allows you to create chips with a high recording density; it is compact, less energy-consuming to use and has a higher operating speed (compared to hard drives). The main disadvantage at the moment is the fairly high cost.

Cloud storage

With the development of the World Wide Web, increasing speeds and mobile Internet, numerous cloud storage systems have appeared, in which data is stored on numerous servers distributed over the network. Data is stored and processed in the so-called virtual cloud and the user has access to them if he has access to the Internet. Physically, servers can be located remotely from each other. There are both specialized services like Dropbox, as well as options from software or device manufacturing companies. Microsoft has OneDrive (formerly SkyDrive), Apple has iCloud, Google Drive, and so on.

The accumulation of knowledge is the basis of the foundations of any civilization. But human memory is imperfect and unable to accommodate all the knowledge and experience that passes from generation to generation. Therefore, since ancient times, people have used a wide variety of storage media, from stone and animal skins to high-quality paper. At the same time, despite the improvement of media types, the recording principle itself and the structure of data have remained virtually unchanged over several millennia.

A qualitative leap occurred only when a person needed to teach a machine to understand recorded information.

More than two hundred years ago, in 1808, the French inventor Joseph Marie Jacquard created a machine for producing fabrics with complex patterns. The uniqueness of this device was that the first software-controlled machine was actually designed and built. The sequence of machine actions when creating a pattern was recorded on special cardboard punched cards in the form of holes punched in a certain order.

It is unlikely that Jacquard imagined how brilliant the future was destined for his invention. Not the machine, but the principle of recording information in the form of binary code, which became the basis of the alphabet of all computers.

Later, Jaccard's ideas were used in automatic telegraphs, where a sequence of Morse code signals was recorded on punched tapes, in Charles Babbage's Analytical Engine, which became the prototype of modern computers, in Herman Hollerith's statistical tabulator and, of course, in the first computers of the twentieth century. Due to their simplicity, various versions of punched cards and punched tapes have become widespread in computer technology and program-controlled machines. Such storage media were used until the mid-80s, when they were finally replaced by magnetic media.

Punched cards and paper tapes

Years of life: 1808–1988

Memory capacity: up to 100 KB

Ease of manufacture, possibility of use in the most low-tech devices

– Low recording density, low read/write speed, low reliability, inability to rewrite information

NATURAL MAGNETISM

Punched cards and punched tapes, for all their advantages and rich history, had two fatal flaws. The first is very low information capacity. A standard punched card held only 80 characters or about 100 bytes; to store one megabyte of information would require more than ten thousand punched cards. The second is the low reading speed: the input device could swallow a maximum of 1000 punch cards per minute, that is, only 1.6 kilobytes per second. The third is the impossibility of rewriting. One extra hole - and the storage medium becomes unusable, like all the information on it.

In the middle of the 20th century, a new principle of information storage was proposed, based on the phenomenon of residual magnetization of certain materials. Briefly, the principle of operation is as follows: the surface of the carrier is made of a ferromagnet, after exposure to a magnetic field, the residual magnetization of the substance remains on the material. It is subsequently registered by reading devices.

The first signs of this technology were magnetic cards, the size and functions of which coincided with conventional punched cards. However, they were not widely used and were soon supplanted by more capacious and reliable magnetic tape drives.

These storage devices have been widely used in mainframe computers since the 50s. Initially, they were huge cabinets with a tape mechanism and reels of tape on which information was recorded. Despite its advanced age, the technology has not died and is still used today in the form of streamers. These are storage devices made in the form of a compact cartridge with magnetic tape, designed for backing up information. The key to their success is large capacity, up to 4 TB! But for any other tasks they are practically unsuitable due to the extremely low speed of data access. The reason is that all information is recorded on magnetic tape, therefore, in order to access any file, it is necessary to rewind the tape to the desired section.

A fundamentally different approach to data recording is used in floppy disks. This is a portable storage device, which is a disk coated with a ferromagnetic layer and enclosed in a plastic cartridge. Floppy disks appeared as a response to users' need for pocket-sized storage media. However, the word “pocket” is not entirely suitable for early samples. There are several formats of floppy disks depending on the diameter of the magnetic disk inside. The first floppy disks, which appeared in 1971, were 8-inch, that is, with a disk diameter of 203 mm. So the only way to put them was in a folder for papers. The volume of recorded information was as much as 80 kilobytes. However, after two years this figure increased to 256 kilobytes, and by 1975 - to 1000 kilobytes! It was time to change the format, and in 1976 5-inch (133 mm) floppy disks appeared. Their volume was initially only 110 KB. But technology improved, and already in 1984, “high-density recording” floppy disks with a capacity of 1.2 MB appeared. This was the “swan song” of the format. Also in 1984, 3.5-inch floppy disks appeared, which can rightfully be called pocket-sized. According to legend, the size of 3.5 inches (88 mm) was chosen on the principle that a floppy disk would fit in a shirt's breast pocket. The volume of this media was initially 720 KB, but quickly grew to the classic 1.44 MB. Later, in 1991, 3.5-inch Extended Density floppy disks with an extended density of 2.88 MB appeared. But they were not widely used, because a special drive was required to work with them.

A further development of this technology was the famous (in some places infamous) Zip. In 1994, Iomega launched a drive with a record capacity for that time - 100 MB. The principle of operation of Iomega Zip is the same as that of conventional floppy disks, but thanks to the high recording density, the manufacturer managed to achieve a record storage capacity. However, Zips turned out to be quite unreliable and expensive, so they could not fill the niche of three-inch floppy disks, and were subsequently completely replaced by more advanced storage devices.

Floppy disks

Years of life: 1971 - to this day

Memory capacity: up to 2.88 MB

Compact size, low cost

– Low reliability, vulnerable case, low recording density

Magnetic tape

Years of life: 1952 - to this day

Memory capacity: up to 4 TB

Rewrite capability, wide range of operating temperatures (from -30 to +80 degrees), low cost of media

– Low recording density, inability to instantly access the desired memory cell, low reliability

Magnetic tape drives were huge cabinets with a tape drive mechanism and reels of tape onto which information was recorded.

STRICT RULES

The hard drive, Hard Disk Drive, is the main storage device in almost all modern computers.

In general, the principle of operation of both existing and developed hard drives is based on the phenomenon of residual magnetization of materials. But there are some nuances here. The direct storage medium in a hard drive is a block of one or more round plates coated with a ferromagnet. The reading head, moving over the surface of high-speed rotating disks, records information by magnetizing billions of tiny areas (domains) or reads data by registering a residual magnetic field.

The smallest cell of information in this case is one domain, which can be either a logical zero or a one. Thus, the smaller the size of one domain, the more data can be crammed onto one hard drive.

The first HDD appeared in 1956. The device consisted of 50 disks with a diameter of 600 mm each, rotating at a speed of 1200 rpm. The dimensions of this HDD were comparable to a modern two-chamber refrigerator, and the capacity was as much as 5 MB.

Since then, the recording density of hard drives has increased more than 60 million times. Over the past decade, manufacturing companies have steadily doubled the capacity of disks every year, but now this process has stopped: the maximum possible recording density has been achieved for the materials and, most importantly, technologies currently in use.

The most common now is the so-called parallel recording. Its meaning is that the ferromagnet to which data is transferred consists of many atoms. A certain number of such atoms together constitute a domain - a minimal cell of information. Reducing the size of the domain is only possible to a certain limit, since the ferromagnetic atoms interact with each other and at the junction of the logical zero and one (regions with oppositely directed magnetic moments) can lose stability. Therefore, a certain buffer zone is required to ensure reliable information storage.

In parallel recording, magnetic particles are placed in such a way that the magnetic direction vector is parallel to the plane of the disk. With perpendicular recording, the magnetic particles are located perpendicular to the surface of the disk.

In parallel recording, magnetic particles are placed in such a way that the magnetic direction vector is parallel to the plane of the disk. From a technology point of view, this is the simplest solution. At the same time, with such recording, the strength of interaction between domains is the highest, so a large buffer zone is needed, and, consequently, a larger size of the domains themselves. So the maximum density for parallel recording is about 23 Gbit/cm2, and this height has already been practically reached.

Further increasing the capacity of hard drives is possible by increasing the number of working plates in the device, but this method is a dead end. The sizes of modern HDDs are standardized, and the number of disks used in them is limited by design requirements.

There is another way - using a new record type. Since 2005, hard drives using the perpendicular recording method can be found on sale. With this recording, magnetic particles are located perpendicular to the surface of the disk. Due to this, the domains weakly interact with each other, since their magnetization vectors are located in parallel planes. This allows you to seriously increase the information density - the practical ceiling is estimated at 60-75 Gbit/cm2, i.e. 3 times more than for parallel recording.

But the most promising technology is HAMR. This is the so-called thermal magnetic recording method. In essence, HAMR is a further development of perpendicular recording technology, with the only difference being that at the time of recording, the desired domain is subjected to short-term (about a picosecond) spot heating by a laser beam. Thanks to this, the head can magnetize very small areas of the disk. HAMR-HDD is not yet publicly available for sale, but prototypes demonstrate a record recording density of 150 Gbit/cm2. In the future, according to representatives of Seagate Technology, the density will be increased to 7.75 Tbit/cm2, which is almost 350 times higher than the maximum density for parallel recording.

HDD with parallel recording

Years of life: 1956 - to this day

Memory capacity: up to 2 TB at the moment

Possibility of instant transition to the desired information cell, good price/quality ratio

– Insufficient recording density today, obsolete technology

HDD with perpendicular recording

Years of life: 2005 - near future

Memory capacity: up to 2.5 TB at the moment

High recording density

– More complex manufacturing technology, high price, low reliability of new high-capacity models

HAMR-HDD

Years of life: 2010 - near future

Memory capacity: time will tell

Even higher recording density

– Particularly complex manufacturing technology and the corresponding high price

OPTICS ON THE MARCH

Despite the constant increase in the capacity of stationary hard drives, there is a need for compact and mobile storage media. Today, CDs and DVDs are the leaders in this area. Virtually any information - music, software, films, encyclopedias or clipart - can be purchased on these media.

The first representative of this technology is LD (Laser Disc), developed back in 1969. These discs were intended primarily for home theaters, but despite a number of advantages over VHS and Betamax video cassettes, they were not widely used. The next representative of optical media turned out to be much more successful. It was a well-known CD (CD, Compact Disc). It was developed in 1979 and was originally intended for recording high-quality music. But in 1987, through the efforts of Microsoft and Apple, CDs began to be used in personal computers. Thus, users had at their disposal a compact and reliable high-capacity storage medium: the standard volume of 650 MB for the late 80s seemed inexhaustible.

The CD has remained virtually unchanged over the past 20 years. The carrier is a kind of “sandwich” consisting of three layers. The basis of the CD is a polycarbonate substrate, onto which a thin layer of metal (aluminum, silver, gold) is sprayed. This layer is actually where the recording is made. The metal coating is covered with a layer of protective varnish, and all sorts of pictures, logos, names and other identification marks are applied to it.

The operating principle of optical discs is based on changing the intensity of reflected light. On a regular CD, all information is recorded on one spiral track, which is a sequence of depressions, pits (from the English pit - “depression”). Between the recesses there are areas with a smooth reflective layer, lands (from the English land - “earth, surface”). The data is read using a laser beam focused into a light spot with a diameter of about 1.2 microns. If the laser hits the land, a special photodiode registers the reflected beam and records a logical one. If the laser hits the pit, the beam is scattered, the intensity of the reflected light decreases and the device records a logical zero.

The first laserdiscs were read-only. They were manufactured strictly in factory conditions and pits were applied to them by stamping directly onto a bare polycarbonate substrate, after which the discs were coated with a reflective layer and protective varnish.

But already in 1988, CD-R (Compact Disc-Recordable) technology appeared. Disks made using this technology could be used to record information once using a special write drive. To do this, another layer of thin organic dye was placed between the polycarbonate and the reflective layer. When heated to a certain temperature, the dye was destroyed and darkened. During the recording process, the drive, controlling the laser power, applied a sequence of dark dots to the disk, which, when read, were perceived as pits.

Ten years later, in 1997, CD-RW (Compact Disc-Rewritable) was created - a rewritable compact disc. Unlike CD-R, here a special alloy was used as a recording layer, capable of transitioning from a crystalline state to an amorphous state and back under the influence of a laser beam.

Years of life: 1972–2000

Memory capacity: 680 MB

First commercial sample of optical storage media

– It was used only as a video and audio carrier and was not inferior in size to vinyl discs, which created certain inconveniences

Years of life: 1982 - to this day

Memory capacity: 700 MB

Compactness, relative reliability, low cost

– Low, by modern standards, capacity, obsolete technology

NEW GENERATION BLANKS

In the mid-90s, when the CD era was in full swing, visionary manufacturers were already working on improving optical discs. In 1996, the first DVDs (Digital Versatile Disc) with a capacity of 4.7 GB appeared on sale. New storage media used the same principle as CDs, only a laser with a shorter wavelength was used for reading - 650 nm versus 780 nm for CDs. This seemingly simple change made it possible to reduce the size of the light spot, and, consequently, the minimum size of the information cell. Therefore, a DVD disc could contain 6.5 times more useful information than a CD.

In 1997, the first recordable DVD-Rs went on sale, also using the technology tested on CD-Rs. However, these innovations reached the general public only a few years later, since the first DVD-R burner cost about $17,000, and blanks cost $50 apiece.

Today DVD has become an integral part of the computer industry. But he doesn’t have long to live either. Rapid progress in the field of high technology and growing user needs require new, more capacious media.

The first sign was double-layer DVDs. In them, information is recorded at two different levels, the usual lower and translucent upper. By changing the laser focus, data can be read from both layers in turn. These DVDs hold 8.5 GB of information. Then came dual-layer, double-sided DVDs. These disks have working sides on both sides and contain two layers of information. Storage capacity has increased to 17 GB.

At this point, the ceiling of DVD technology was reached. Further increasing the number of layers seems to be an unnecessarily complex problem; the thickness of the disk is still limited, so it is very difficult to squeeze something in there. In addition, even with a two-layer system, there were many complaints about the quality of reading information, and it’s scary to think how many errors a hypothetical three-layer DVD could produce.

Manufacturers solved (temporarily, of course) the problem of increasing capacity by creating a new format. Or rather, two at once: HD-DVD and Blu-ray. Both technologies use a blue laser with a wavelength of 405 nm. As we have already said, reducing the wavelength also allows you to reduce the minimum size of the memory cell and, therefore, increase the recording density. The emergence of two new types of disks at once provoked the so-called “format war”, which lasted about two years. Ultimately, despite certain advantages, HD-DVD lost this battle. According to many experts, the main role in this was played by the extremely strong support of the Blu-ray format by American film studios.

"Blue Beam" is now the only high-capacity optical storage media that can be found on sale. Disks 23, 25, 27 and 33 GB. There are also dual-layer samples with capacities of 46, 50, 54 and 66 GB.

DVD

Years of life: 1996 - to this day

Memory capacity: up to 17.1 GB

The most popular storage medium: the vast majority of music, films and various software are distributed on DVD

– Outdated technology

HD-DVD

Years of life: 2004–2008

Memory capacity: up to 30 GB

High capacity plus relatively low price due to cheaper production

– Lack of support from the American film industry.

Blu-ray

Years of life: 2006 - to this day

Memory capacity: up to 66 GB

High storage capacity, support for Hollywood “monsters”

– High cost of drives and media, since production requires fundamentally new equipment

GIGABYTE RACE

The disk drive market is a very tasty morsel. Therefore, in the near future we should expect, if not a shift of Blu-ray from its leading position, then a new war of formats.

A unique feature of the holographic method is the ability to record a huge amount of information at almost one point. This gives manufacturers reason to claim that the already reached ceiling of 3.6 TB is far from the limit.

There are a number of technologies vying for user wallets. For example, HD VMD (High Density - Versatile Multilayer Disc). This format was introduced in 2006 by a little-known British company, New Medium Enterprises. Here the manufacturer has taken the path of increasing the number of recording layers in one disc - there are already 20 of them. Thanks to this, the maximum capacity of HD VMD today is 100 GB. In general, it is unlikely that the small New Medium Enterprises will be able to seriously displace the multimedia giants. But thanks to the declared low cost of disks and drives for them (due to the use of a cheaper red laser with a wavelength of 650 nm), the British can theoretically count on a certain popularity of their products. If, of course, it even gets to the market.

Another contender is the Ultra Density Optical (UDO) format. Development began back in June 2000, and now it is a completely finished device available on the market. Here the emphasis was placed on increasing the accuracy of beam focusing. With a laser wavelength of 650 nm, the UDO disk holds from 30 to 60 GB of information. There are also media that use blue laser (405 nm), in which case the maximum UDO capacity reaches 500 GB. But you have to pay for everything: the increase in laser accuracy has caused a serious increase in the cost of drives. The media itself comes in the form of a 5.35-inch cartridge with a disk inside (for protection from external influences) and is sold for $60-70. Today, UDO technology is used mainly by large companies for archiving information and creating backup copies of data.

HD VMD (High Density - Versatile Multilayer Disc)

Years of life: 2006 - near future

Memory capacity: up to 100 GB

High capacity, relatively low cost

– Lack of support from major market players, which will certainly cause the death of the format

UDO (Ultra Density Optical)

Years of life: 2000 - to this day

Memory capacity: up to 120 GB

Good capacity

– High cost of drives and media, targeting a highly specialized market for data archiving devices

HOLOGRAPHY BURNS

Despite the abundance of optical disc formats, technology already exists that will certainly leave all competitors behind in the future. We are talking about a holographic recording. The benefits of this technology and its potential are enormous. Firstly, if in conventional optical disks information is written to a layer using individual information cells, then in holographic memory the data is distributed throughout the entire volume of the medium, and several million cells can be written in one clock cycle, due to which the speed of writing and reading increases dramatically. Secondly, due to the distribution of information in three dimensions, the maximum capacity of the carrier reaches truly stratospheric heights.

Work in this direction began about ten years ago, and today there is a completely intelligible technology by which 1.6 TB of information can be recorded on a standard-sized disk. At the same time, the read speed is 120 MB/s.

The operating principle of holographic recording is implemented as follows. The laser beam is divided into two streams with the same wavelength and polarization using a translucent mirror. A spatial light modulator, which is a flat stencil, converts digital information into a sequence of transparent and opaque cells that correspond to logical ones and zeros. The signal beam, having passed through this lattice and received a piece of information, is projected onto the carrier. The second beam - the reference beam - falls at an angle into the same area of the disk. In this case, at the points where the reference and signal beams intersect, the amplitudes of the waves are added (interference), as a result of which the beams jointly burn through the photosensitive layer, recording information on the medium. Thus, in one clock cycle, all the information that can be mastered by the resolution of the light modulator is recorded at once. Today this is about a million bits at a time.

Data is read using a reference beam, which, passing through the body of the carrier, projects the recorded hologram onto the photosensitive layer, and the latter converts the “grid” falling on it into a sequence of zeros and ones.

A unique feature of the holographic method is the ability to record a huge amount of information at almost one point. Thanks to this, you can effectively use the entire volume of the media. The practical maximum capacity of holographic disks is not known exactly, but manufacturers claim that the 3.6 TB ceiling they have already reached is far from the limit.

Holographic discs

Years of life: near future

Memory capacity: up to 1 TB

Very, very high capacity while maintaining compact media dimensions

- Time will show

HDD + LASER

In 2006, Daniel Stanciu, who was working on his doctoral dissertation, and Dr. Frederick Hansteen discovered a way to change the polarity of a magnet using light radiation. It must be said that previously this was considered impossible in principle. It is not surprising that Daniel Stansiu successfully defended his doctoral dissertation, and the technology itself, which received a rather strange name - pure optical magnetization inversion - has already found potential application.

So, using a laser beam, you can magnetize domains of hard drives, i.e., do the same work that the write head is currently doing, but much faster. The recording speed on a regular hard drive does not exceed 100–150 Mbit/s. In the prototype of a “laser” hard drive, this figure is currently 1 Tbit/s or 1,000,000 Mbit/s. Scientists are confident that this is not the limit - they expect to increase the recording speed to 100 Tbit/s. In addition, using a laser, you can significantly increase the density of recorded information, which, theoretically, makes laser hard drives one of the most promising technologies for storing and recording data.

But today there is no information about the design of the read head for such HDDs. Using a laser, you can only record information. It cannot detect the magnetization of domains. Therefore, for reading you will need to use standard magnetic heads. In addition, do not forget that both the write speed and the read speed of the HDD directly depend on the rotation speed of the disks. So the optimistic statements of scientists look somewhat strange. To achieve 1 Tbit/s, you need to spin the disk to such speeds that it will probably shatter into pieces under the influence of a monstrous centrifugal force or even burn out from friction with the air. Of course, the use of a certain optical beam redirection system allows you to completely abandon disk rotation when recording. But reading is still performed by the magnetic head, which vitally needs to slide over the surface of the disk.

In short, the prospects for pure optical magnetization inversion technology, although attractive, are very vague.

Laser HDD

Years of life: near future

Memory capacity: time will tell

High density and speed of recording information, in the future - the possibility of reducing the number of moving parts of the disk

– There are too many questions that no one gives answers to.

BRILLIANT FUTURE?

Disks are disks, but the average user sometimes needs a compact, capacious and, most importantly, easy-to-use storage device. Today, flash drives, or, scientifically speaking, USB Flash Drives, are used for this purpose. The flash memory of this device is an array of transistors (cells), each of which can store one bit of information.

Such a medium has many advantages. Flash drives, unlike their predecessors, have no moving parts. They are compact, reliable and capable of storing quite significant amounts of information, and manufacturers are tirelessly working to increase their capacity. There are flash drives that can hold 8, 12, and even 64 GB of data. True, such toys compete in cost with a first-class computer in the all-inclusive package, but this is a temporary phenomenon. Until recently, a 1 GB flash drive cost a fortune, but now it is available to every student receiving a scholarship.

Another advantage of a flash drive is ease of use. The flash drive is connected to the computer's USB port, the operating system detects the new device, and the contents of the flash drive are displayed as an additional disk in the system. Accordingly, working with files is no different from working with a regular hard drive. No additional programs are required, no need to rack your brains over the compatibility of devices and formats, or look closely at the device manufacturer, wondering whether it will fit your computer or not.

Flash memory is reliable, not afraid of vibrations, does not make noise, consumes little energy, and the speed of information exchange is close to that of standard hard drives. Flash memory, due to the absence of moving parts, is highly reliable, vibration-resistant, noise-free and consumes little energy. The benefits are obvious.

Data is read using the holographic method using a reference beam, which, passing through the body of the carrier, projects the recorded hologram onto the photosensitive layer, and this one converts the “grid” falling on it into a sequence of zeros and ones.

Today, laptop computers are already being produced in which, instead of the usual HDDs, SSD (Solid State Drive) chips are installed, the so-called solid-state drives based on flash memory. Fundamentally, such storage devices are no different from ordinary flash drives. Laptops with SSDs, due to their low power consumption, can work almost twice as long as those equipped with conventional hard drives. However, flash memory also has its serious disadvantages. Firstly, the data exchange speed in SSDs is still significantly behind those of hard drives. But this problem will be solved in the very near future. The second drawback is much more serious. Flash memory, by design, can withstand a limited number of erase and write cycles - about 100,000 cycles. Without going into technical details, we can make a diagnosis: the process of recording and erasing data leads to physical wear and tear of memory cells at the electronic level. However, having picked up a calculator and done the simplest calculations, the user’s face brightens and joyfully declares that even if the flash drive is completely refilled ten times a day, 100,000 cycles will last for 27 years! But in practice, flash memory (for example, a memory card in a camera), which is intensively used every day, can fail after two to three years of use.

Flash memory

Years of life: 1989 - to this day

Memory capacity: up to 80 GB

Easy to use, low power consumption, reliable

– Limited number of write/erase cycles

Today, progress in the field of computer technology in general and storage devices in particular is rapidly changing the world.

Looking into the future is a thankless task, but we can say with confidence: if manufacturers cannot overcome the only serious drawback of flash memory, fail to achieve the HDD capacity users need, or create a simple and reliable holographic disk, they will inevitably come up with another way to store information.

Cheap, reliable, compact, fast.