1) Paper media.
One of the most common information carriers is paper. At school, we write down information in a notebook, we 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 their
queue are paper media
The first computers worked on punch cards.(fig. 6, fig. 7)
Magnetic tape has proven to be quite reliable, durable and affordable for every information carrier.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 school desk for "research" by its students)
In modern computers, the following magnetic media are used as information carriers:
1) diskette(on which you can put the data of 3000 punched cards).
2) hard magnetic disk or winchester ( stores 100,000 or more floppy disks). Inside the hard metal case there are several tens of magnetic disks located on one axis (Fig. 12). Recording or reading of information is provided by several magnetic heads. In order to preserve information and functionality, hard magnetic disks must be protected from shocks and sudden changes in the position of the system unit (you cannot
Tilt and turn over during operation).
3) streamers(stream cartridges) - devices that record or read audio information (Fig. 13). This media contains a magnetic tape.
Laser discs are made of plastic, covered with a thin layer of metal and a transparent varnish on top that protects against minor scratches or dirt. Writing or reading information in a CD-drive is carried out using laser light. When recording, the laser beam burns out microscopic depressions on the surface of the disc, thereby encoding information (when reading, the laser beam is reflected from the surface of the rotating disc). These discs should be protected from dust and scratches.Distinguish between CD and DVD discs.
Questions: - What information can be burned onto CDs and DVDs?(DVD is called a digital video disc, therefore it is possible to record video and audio information 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 disc. These discs include tutorials, game programs, electronic textbooks, etc.
CD- R, DVD- R- you can write information to the disc only once. Data cannot be deleted after recording.
CD- RW, DVD- RW- you can record information on such a disk several times.
Introduction ………………………………………………………………………… ... 3
Information carriers ………………………………………………………… 4
Encoding and reading information .. ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
Development prospects ……………………. …………………………………… .15
Conclusion ……………………………………………………………………… .18
Literature. …………………………………………………………………… 19
Introduction
In 1945, John von Neumann (1903-1957), an American scientist, put forward the idea of using external storage devices to store programs and data. Neumann developed a structural schematic diagram computer. All modern computers correspond to the Neumann scheme.
External memory is designed for long-term storage of programs and data. External memory devices (storage devices) are non-volatile; turning off the power does not result in data loss. They can be embedded in system unit or made in the form of independent units connected with the system unit through its ports. According to the method of writing and reading, drives are divided, depending on the type of medium, into magnetic, optical and magneto-optical.
Information coding is the process of forming a specific representation of information. The computer can only process information presented in numerical form. All other information (for example, sounds, images, instrument readings, etc.) for processing on a computer must be converted into numerical form. As a rule, all numbers in a computer are represented using zeros and ones (and not ten digits, as is customary for people). In other words, computers usually work in a binary number system, since the devices for their processing are much simpler.
Reading information - retrieving information stored in a memory device (memory) and transferring it to other devices of a computer. Reading information is performed during the execution of most machine operations, and sometimes it is an independent operation.
In the course of the essay, we will consider the main types of information carriers, coding and reading information, as well as development prospects.
Information carriers
Historically, the first storage media were punched tape and punched card input / output devices. They were followed by 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 spools. There were two types of coils: supply and receive. Tapes are delivered to users on feed reels and do not require additional rewinding when installed in drives. The tape is wound on the spool with the working layer inside. Magnetic tapes are indirect drives. This means that the search time for any record depends on its location on the carrier, since the physical record does not have its own address and to view it, you need to view the 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 carrier. Each physical record on the media has an address that provides direct access to it, bypassing the rest of the records. The next type of recording devices were packs of removable magnetic disks, consisting of six aluminum disks. The capacity of the entire package was 7.25 MB.
Let's consider in more detail modern storage media.
1. A floppy disk drive (floppy disk drive).
This device uses as a storage medium floppy disks - 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 changes. If on a standard 5'25 "floppy disk you can fit up to 720 Kbytes of information, then on a 3'5" floppy disk there are already 1.44 Mbytes. Floppy disks are universal, suitable for any computer of the same class equipped with a disk drive, can be used for storing, accumulating, distributing and processing information. The floppy drive is a parallel access device, so all files are equally easily accessible. The disk is covered on top with a special magnetic layer that provides data storage. Information is recorded on both sides of the disc along tracks that are concentric circles. Each track is divided into sectors. The data recording density depends on the density of the tracks on the surface, that is, the number of tracks on the surface of the disc, as well as on the density of the information along the track. The disadvantages include small capacity, which makes long-term storage of large amounts of information almost impossible, and not very high reliability of the floppy disks themselves. Nowadays, floppy disks are practically not used.
2. Hard 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 at the same time;
- high speed of data access.
Of the shortcomings, only the absence of removable media can be distinguished, although external hard drives and systems are currently used Reserve copy.
The computer has the ability to use a special system program conditionally split one disk into several. Such disks that do not exist as a separate physical device, but represent only a portion of one physical disk, are called logical disks. Logical drives names are assigned, which are the letters of the Latin alphabet [C:], [E:], etc.
3. Compact disc drive (CD-ROM)
These devices use the principle of a focused laser beam reading the grooves on the metallized CD carrier layer. This principle allows you to achieve a high density of information recording, and, consequently, a large capacity with minimal dimensions. A compact disk is an excellent means of storing information, it is cheap, practically unaffected by 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 - a relatively small amount of information storage.
4. DVD
BUT) Differences between DVDs and regular CD-ROMs
The most basic difference is, of course, the amount of recorded information. If a regular CD-disc can record 650 MB (although recently there are 800 MB discs, but not all drives will be able to read what is recorded on such a medium), then one DVD will fit from 4.7 to 17 GB. The DVD uses a laser with a shorter wavelength, which made it possible to significantly increase the recording density, and in addition, DVD implies the possibility of two-layer information recording, that is, there is one layer on the surface of the compact, on top of which another, semitransparent layer is applied, and the first is read through the second in parallel ... There are also more differences in the carriers themselves than it 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 conventional CDs. Naturally, a disc of this thickness will be much more fragile than a classic blank. Therefore, another 0.6 mm is usually filled with plastic from both sides to get the same 1.2 mm. But the main bonus of such a protective layer is that due to its small size on one compact it became possible to record information from both sides, that is, to double its capacity, while leaving the dimensions practically 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, 13.24 GB, or 6.5 hours of video;
5. DVD18 - Dual layer, double sided disc, 17 GB, or more than eight hours of video.
The most popular standards are DVD5 and DVD9.
IN) Capabilities
The situation with DVD media now resembles that with CDs, on which for a long time also stored only music. Now you can find not only films, but also music (the so-called DVD-Audio) and collections of software, and games, and films. Naturally, the main area of use is film production.
D) DVD Sound
Soundtrack can be encoded in many formats. The most famous and commonly 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
CDs and DVDs are equally susceptible to mechanical damage. That is, a scratch is a scratch. However, due to the much higher recording density, the loss on a DVD will be more significant. Now there are programs that can recover information even from damaged disks, albeit skipping bad sectors.
Fast growing market for portable hard drives designed to transport large amounts of data, has attracted the attention of one of the most large manufacturers hard drives. Company Western digital announced the release of two models of devices at once under the name WD Passport Portable Drive. The 40 and 80 GB versions are now on sale. Portable Devices The WD Passport Portable Drive is based on the WD Scorpio EIDE 2.5-inch HDD. They are packaged in a rugged case, equipped with Data Lifeguard technology, and do not require an additional power source (powered via USB). The manufacturer notes that the drives do not heat up, work 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, non-volatility, high speed of information transfer, protection from mechanical and electromagnetic influences, the ability to use 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, textual, graphic, audio and video information. All these types of information in a computer are represented in binary code, that is, an alphabet with a power of 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 the machine binary code carries the amount of information equal to one bit. This conclusion can be made by considering the numbers of the machine alphabet as equiprobable events. When writing a binary digit, it is possible to realize the choice of only one of two possible states, which means that it carries an amount of information equal to 1 bit. Consequently, two digits carry information 2 bits, four bits - 4 bits, etc. To determine the amount of information in bits, it is enough to determine the number of digits in the binary machine code.
BUT) Encoding text information
Currently, most of the users using a computer processes textual information, which consists of characters: 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 a text information you can use the 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 the corresponding decimal code from 0 to 255. It must be remembered that at present
| Binary code | Decimal code | KOI8 | CP1251 | CP866 | Mac | ISO |
| 11000010 | 194 | b | IN | - | - | T |
time for encoding Russian letters use five different code
tables (KOI - 8, CP1251, CP866, Mac, ISO), and texts encoded using one table will not be displayed correctly in another encoding. This can be clearly represented as a fragment of the combined character encoding table. Different symbols are assigned to the same binary code. However, in most cases, the user takes care of the transcoding of text documents, and special programs- converters that are built into applications.
B) Graphic information encoding
In the mid-1950s, for large computers, which were used in scientific and military research, for the first time in a graphical form, data presentation was implemented. Without computer graphics, it is difficult to imagine not only the computer, but also the completely material world, since data visualization is used in many spheres of human activity. Graphic information can be presented in two forms: analog or discrete. A canvas that changes color continuously is an example of an analog representation, while an image printed with an inkjet printer consisting of individual dots of different colors is a discrete representation. By splitting the graphic image (sampling), the graphic information is converted from an analog form to a discrete one. In this case, coding is performed - the assignment of a specific value to each element in the form of a code. When encoding an image, its spatial sampling occurs. It can be compared to the construction of an image from a large number of small colored fragments (mosaic method). The whole image is divided into separate points, each element is assigned a code of its color. In this case, the quality of encoding will depend on the following parameters: the size of the point and the number of colors used. The smaller the dot size, which means that the image is composed of more dots, the higher the encoding quality. The more colors are used (that is, the image point can take more possible states), the more information each point carries, and, therefore, the coding quality increases. Creation and storage of graphic objects is possible in several forms - 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 volumetric models of objects in virtual space. For each type, its own method of encoding graphic information is used.
IN) Audio coding
Since childhood, we are faced with recordings of music on different media: gramophone records, cassettes, CDs, etc. Currently, there are two main ways to record sound: analog and digital. But in order to record sound on some medium, it must be converted into an electrical signal. This is done using a microphone. The simplest microphones have a membrane that vibrates with sound waves. A coil is attached to the membrane and moves synchronously with the membrane in a magnetic field. An alternating electric current is generated 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 that travels through the air. Sound information can be presented in discrete or analog form. Their difference is that with a discrete presentation of information, a physical quantity changes abruptly ("ladder"), taking on a finite set of values. If the information is presented in analog form, then the physical quantity can take on an infinite number of values that are continuously changing. The vinyl record is an example of analogue storage of audio information, since the soundtrack continuously changes its shape. But analog tape recordings 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 1980s, CDs appeared. They are an example of discrete storage of audio information, since the audio track of a CD contains areas with different 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 with digital dubbing. On multimedia sound cards you can find analog microphone preamplifier and mixer. Consider the processes of converting sound from analog to digital and vice versa. A rough idea of what is happening in sound card, can help to avoid some mistakes when working with sound. Sound waves are converted into an analog alternating electrical signal using a microphone. It goes through the audio path and into an analog-to-digital converter (ADC) - a device that converts the signal into digital form. In a simplified form, the principle of operation of the ADC is as follows: it measures the signal amplitude at regular intervals and transmits further, already through the digital path, a sequence of numbers that carry information about the amplitude changes. During analog-to-digital conversion, no physical conversion occurs. An imprint or sample is, as it were, removed 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 in the form of a sequence of columns, each of which corresponds to a specific numerical value. The digital signal is discrete in nature - that is, discontinuous, so the digital model does not exactly match the analog waveform. The digital sound is output using a digital-to-analog converter (DAC), which, based on the incoming digital data, at the appropriate times, generates an electrical signal of the required amplitude.
Reading information - retrieving information stored in a memory device (memory) and transferring it to other devices of a computer. Reading information is performed during the execution of most machine operations, and sometimes it is an independent operation. Reading can 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 a memory on ferrite cores), or it can be non-destructive (for example, in a memory on magnetic tapes, disks) and, therefore, allowing reuse of information once recorded. Reading information is characterized by the time spent directly on data output from the memory; it ranges from several tens of nanoseconds to several milliseconds.
Consider the process of reading information on the example of a CD. The data from the disc 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 the 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 land), 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-write disks is the way the pits are formed. In the case of a read-only disc, the pits are a kind of relief structure (phase diffraction grating), and the optical depth of each pit is slightly less than a quarter of the wavelength of the laser light, which leads to a phase difference of half the wavelength between the light reflected from the pit and the light reflected from the landing. As a result, in the plane of the photodetector, the effect of destructive interference is observed and a decrease in the signal level is recorded. In the case of CD-R / RW, the pit is an area with higher light absorption than a land (amplitude diffraction grating). As a result, the photodiode also registers a decrease in the intensity of the light reflected from the disk. The length of the pit changes both the amplitude and the duration of the recorded signal.
CD read / write speed is indicated in multiples of 150 Kb / s (i.e. 153 600 bytes / s). For example, a 48-speed drive provides a maximum CD read (or write) speed of 48 x 150 = 7200 KB / s (7.03 MB / s).
Development prospects
The development of information recording media goes in 3 main directions:
a) increase in volume useful information on a specific medium (especially important for optical discs);
b) improving the quality of technical equipment (access time to information, data transfer rate);
c) a gradual increase in the level of compatibility of various formats of the media used.
Promising types of storage media include: Eye-Fi, Holographic Versatile Disc, Millipede.
Eye-fi- a kind of SD flash memory cards with built-in hardware elements to support Wi-Fi technology.
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 global Internet to pre-programmed resources that provide photo or video hosting of this kind of content. Administration, access to settings and operation of such cards is carried out via Wi-Fi from a PC or Mac compatible computer through a browser. The card works only through pre-registered Wi-Fi networks, WEP and WPA2 encryption are supported.
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: 2.835g
Holographic multi-purpose disc (Holographic Versatile Disc)- a promising technology for the production of optical discs being developed, which assumes a significant increase in the amount of data stored on a disc in comparison with 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. A green laser reads grid-coded data from a holographic layer close to the surface of the disc, while a red laser is used to read auxiliary signals from a conventional CD layer deep within the disc. The ancillary information is used to keep track of the read position, much like the CHS system on a regular hard drive. On CD or DVD, this information is embedded in the data. The estimated information capacity of these discs is up to 3.9 terabytes (TB), which is comparable to 6,000 CDs, 830 DVDs or 160 single layer Blu-ray discs; data transfer rate - 1 Gbps. Optware was going to release a 200GB drive in early June 2006 and Maxell in September 2006 with a 300GB drive. On June 28, 2007, the HVD standard was approved and published.
Holographic disc structure (HVD)
1. Green laser read / write (532nm)
2. Red positioning / indexing laser (650nm)
3. Hologram (data)
4. Polycarbonate layer
5. Photopolimeric layer (layer containing data)
6. Distans layers
7. Layer reflective green (Dichroic layer)
8. Aluminum reflective layer (reflective red light)
9. Transparent base
P. Depressions
Millipede is a relatively new storage technology developed by IBM. The scanning probe microscope is used to read and write information. Also, scientists from the Pohang University of Science and Technology ( South Korea). They were the first in the world to create material suitable for the creation of millipede memory. The peculiarity of millipid memory is that information is stored in a huge number of nano-pits that cover the surface of the working material. In this case, such a memory is non-volatile, and the data is stored in it for as long as desired. To create a working prototype of millipede memory, Korean electronics engineers have developed a unique polymer material. Only with his help was it possible to create a stably functioning memory device, which is almost ready for implementation in production.
Conclusion
In the course of the essay, the main types of information carriers were considered, the principles of coding and reading information, as well as the prospects for the development of information carriers.
The history of information carriers (punched tapes, punched cards, magnetic tapes, removable and permanent magnetic disks, magnetic drums, packages of removable magnetic disks) were also considered; floppy disk drives, hard disk drives, CDs, DVDs, USB portable drives, USB Flash Drive. Were considered coding (text, graphic, sound) and reading information (for example, reading information from a CD-ROM). The most promising are currently considered Eye-Fi, Holographic Versatile Disc and Millipede.
There are so many concepts in the Russian language that it is sometimes difficult to distinguish between two very similar, but still different definitions. But there are terms that do not carry additional meanings, but have a clear and understandable interpretation. For example, the concept of "electronic media". This is the definition of a tangible medium that records, stores and reproduces data that is processed by computer technology.
How did it all start?
More general meaning of this term is "information carrier" or "information carrier". It defines a material object or environment that is used by a person. Moreover, such an item stores data for a long time without using additional equipment.
If an energy source is needed to store information on electronic media, then a simple data carrier can turn out to be stone, wood, paper, metal and other materials.
Any object that shows data applied to it can be called a carrier of information. It is believed that information carriers are needed for recording, storing, reading, transferring materials.
Features of the
It is not hard to guess that an electronic storage medium is a kind of information storage medium. It also has its own classification, which, although not officially established, is used by many specialists.
For example, electronic media can be single or reusable. This refers to devices:
- optical;
- semiconductor;
- magnetic.
Each of these mechanisms has several types of equipment.
An electronic carrier of information is, first of all, a number of advantages over paper versions. First, thanks to technology, the amount of data backed up can be virtually unlimited. Secondly, the collection and delivery of up-to-date information itself is ergonomic and fast. Thirdly, digital data is presented in a convenient way.
But the electronic medium also has its drawbacks. For example, this can include the unreliability of the equipment, in some cases the dimensions of the device, dependence on electricity, as well as the requirement for the constant availability of a device that could read files from such a digital drive.
Variety: optical discs
An electronic storage medium is a device that can be optical, semiconductor, or magnetic. This is the only classification for such equipment.
In turn, optical devices are also divided into types. This includes laser disc, CD, mini discs, Blu-ray, HD-DVD, and so on. The optical disc is so named because of the information reading technology. Reading from a disc is done using optical radiation.
The idea of this electronic carrier was born a long time ago. The scientists who developed the technology were awarded the Nobel Prize. The way to reproduce information from an optical disc appeared back in 1958.
Now the optical electronic carrier has 4 generations. The first generation included: laser disc, CD and mini disc. In the second generation, DVDs and CD-ROMs became popular. In the third generation, Blu-ray and HD-DVD stand out. In the fourth generation, the Holographic Versatile Disc and SuperRens Disc are being actively developed.
Semiconductor media
The next type of electronic storage medium is semiconductor. This includes flash drives and SSDs.
Flash memory is the most popular electronic storage medium that has semiconductor technology and programmable memory. It is in demand due to its small size, low price, mechanical strength, acceptable volume, speed of operation and low energy consumption.
The disadvantages of this option are limited useful life and dependence on electrostatic discharge. For the first time they started talking about a flash drive in 1984.
An SSD is a semiconductor electronic storage medium also called a solid state drive. It replaced the hard drive, although this moment did not completely replace it, but only became an addition to home systems. Unlike a hard drive, solid state drive based on memory chips.
The main advantages of such a carrier are its compact size, high speed, and durability. But at the same time, it has a great value.
Magnetic disks
And the last type of electronic media are magnetic devices. These include magnetic tapes, floppy disks, and hard drives. Since the first and second equipment is not used now, we will talk about the railway.
A hard disk is a random access device based on magnetic recording technology. At the moment, this is the main storage device for most modern computer systems.
Its main difference from the previous type, a floppy disk, is that the recording is carried out on aluminum or glass plates, which are covered with a layer of ferromagnetic material.
Other options
Despite the fact that, when speaking of electronic media, we often think of devices connected to a computer, this does not mean that this concept is used only in computer technology.
The proliferation of electronic media is associated with the convenience of its use, high speed writing and reading. Therefore, this equipment is replacing paper media.
Documentation
What is a passport with an electronic data carrier? At first, this question can drive a person into a dead end. But if you think about it, you will remember such a thing as a "biometric passport".
This is a state document that certifies the identity and citizenship of the traveler at the time of his moving abroad and staying in another country. In fact, we have before us the same passport, but with some nuances.
The difference between a biometric document and a traditional passport is that the first is a carrier of a specially mounted microcircuit that stores the owner's photo and his personal data.
Thanks to a small microcircuit, you can get the last name, first name and patronymic of the owner of the document, his date of birth, passport number, time of issue and the end of the validity period. According to the sample, the microcircuit must contain the biometric data of a person. This includes a drawing of the iris of the eye or a fingerprint.
Document introduction: advantages and disadvantages
Despite the fact that the biometric passport has long been introduced by many states, some citizens have a negative attitude towards it. But this document has both advantages and disadvantages.
The advantages include the fact that the passage of the border checkpoint now does not take much time. If such places have special equipment that can read a microchip, then border crossing becomes safe and fast.
But not all citizens like a biometric passport. Many believe that the introduction of such a document is a manifestation of total control, which is backed by the US government.
Criminal case
The development of electronic media has affected many areas. This also includes a criminal case. In 2012, the term of electronic information carrier was introduced into the Criminal Procedure Code of the Russian Federation. Thus, such devices could become physical evidence.
Electronic storage media have become an important part in the investigation of a criminal case, subject to certain conditions. For example, the data from the media should be of direct relevance to the investigation. In addition, they must be transmitted by a reliable source that could be verified. The data should have a special kind, for example, represented by video recordings, photographs, screenshots, and so on. When seizing digital information, you must comply with the established laws.
During the investigation of a criminal case, it is necessary to keep records of electronic information carriers. In this case, a log is started in which all devices are registered. Each is assigned an identification number.
The importance of electronic media in a criminal investigation is a controversial issue to this day. Legally, such devices are not attributed to any source of evidence. From here, disagreements can arise.
conclusions
Electronic media for modern people are a real find. With the development of technology, the volume of archives that store data is growing. Every year there are new opportunities for transmitting and reading information.
Information carrier- a physical environment that directly stores information. The main carrier of information for a person is his own biological memory (human brain). A person's own memory can be called RAM... Here the word "operational" is synonymous with the word "fast". Learned knowledge is reproduced by a person instantly. We can also call our own memory internal memory because its carrier - the brain - is inside us.
Information carrier- a strictly defined part of a specific information system, serving for intermediate storage or transmission of information.
The basis of modern information technologies Is a 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 the type of performance, the material from which the media is made, etc. Here is one of the options for classifying information carriers:
Tape media
Magnetic tape- magnetic recording medium, which is a thin flexible tape, consisting of a base and a magnetic working layer. The operating properties of a magnetic tape are characterized by its sensitivity during recording and signal distortion during recording and playback. The most widely used is a multilayer magnetic tape with a working layer of needle-like 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 refer to machine media with direct access. 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 recorded.
Disk drives are the most diverse:
CD-ROM (Compact Disk ROM)
Floppy disk drives (floppy disks), they are also floppy disks, they are also floppy disks
Hard disk drives (HDD), they are also hard drives (popularly just "screws")
Optical CD Drives:
In floppy disk drives (floppy disks or floppy disks) and hard disk drives (hard disk drives or hard drives), the recording, storage and reading of information is based on the magnetic principle, and in laser drives - the optical principle.
Flexible magnetic disks placed in a plastic case. This storage medium is called a floppy disk. The diskette is inserted into a disk drive that rotates the disk at a constant angular velocity. The magnetic head of the drive is installed on a certain concentric track of the disc, on which information is written (or read).
The information capacity of the floppy disk is small and amounts to only 1.44 MB. The speed of writing and reading information is also low (about 50 KB / s) due to the slow rotation of the disk (360 rpm).
Hard magnetic disks.
Hard disk (HDD - Hard Disk Drive) refers to non-removable magnetic disk drives. The first hard drive was developed by IBM in 1973 and had a capacity of 16 KB. Hard magnetic disks are several dozen disks located on one axis, enclosed in a metal case and rotating at a high angular velocity. The speed of writing and reading information from hard disks is quite high (about 133 MB / s) due to the fast rotation of the disks (7200 rpm).
During the operation of the computer, malfunctions occur. Viruses, power outages, software errors - all of these can damage the information stored on your hard drive. Damage to information does not always mean its loss, so it is useful to know how it is stored on the hard disk, because then it can be restored. Then, for example, in the event of a virus damaging the boot area, it is not at all necessary to format the entire disk (!), But, having restored the damaged space, continue normal work with saving all your invaluable data.
Rather fragile and tiny elements are used in hard drives. To preserve the information and performance of hard drives, it is necessary to protect them from impacts and sudden changes in spatial orientation during operation.
Laser drives and discs.
In the early 1980s, the Dutch firm Philips announced it had revolutionized sound reproduction. Its engineers came up with something that is now very popular - these are laser discs and turntables.
Laser drives use the optical principle of reading information. On laser discs CD (CD - Compact Disk, compact disc) and DVD (DVD - Digital Video Disk, digital video disc) information is recorded on one spiral track (like on a gramophone record), containing alternating areas with different reflectivity. The laser beam falls on the surface of the rotating disk, and the intensity of the reflected beam depends on the reflectivity of the track section and acquires values of 0 or 1. To preserve information, laser disks must be protected from mechanical damage (scratches), as well as from dirt. Laser discs store information that was recorded on them during the manufacturing process. Writing new information to them is impossible. Such discs are produced by stamping. There are CD-R and DVD-R discs on which information can be recorded only once. On CD-RW and DVD-RW discs, information can be recorded / rewritten many times. Different types of discs can be distinguished not only by their markings, but also by the color of the reflective surface.
Flash memory devices.
Flash memory is a non-volatile type of memory that allows you to write and store data on microcircuits. Flash-based devices have no moving parts, which ensures high data security when used in mobile devices.
Flash memory is a microcircuit housed in a miniature package. To write or read information, drives are connected to a computer via a USB port. The information capacity of memory cards reaches 1024 MB.
Information carrier- a physical environment that directly stores information. The main carrier of information for a person is his own biological memory (human brain). A person's own memory can be called working memory. Here the word "operational" is synonymous with the word "fast". Learned knowledge is reproduced by a person instantly. We can also call our own memory internal memory, since its carrier - the brain - is inside us.
Information carrier- a strictly defined part of a specific information system, serving for intermediate storage or transmission of information.
The basis of modern information technology is a 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 the type of performance, the material from which the media is made, etc. One of the options for the classification of information carriers is shown in Fig. 1.1.
The list of information carriers in Fig. 1.1 is not exhaustive. We will consider some storage media in more detail in the following sections.
Data storage is a way of spreading information in space and time. The way of storing information depends on its medium (a book is a library, a picture is a museum, a photograph is an album). This process is as ancient as the life of human civilization. Already in ancient times, a person was faced with the need to store information: notches in trees so as not to get lost during a hunt; counting objects with the help of pebbles, knots; depictions of animals and hunting episodes on the walls of the caves.
The computer is designed for compact storage of information with the ability to quickly access it.
Information system is a repository of information, equipped with procedures for entering, searching and 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 storage information
TAPE MEDIA
Magnetic tape- magnetic recording medium, which is a thin flexible tape, consisting of a base and a magnetic working layer. The operating properties of a magnetic tape are characterized by its sensitivity during recording and signal distortion during recording and playback. The most widely used is a multilayer magnetic tape with a working layer of needle-like 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 machine media with direct access. 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 recorded.
Disk drives are the most diverse:
Floppy disk drives (floppy disks), they are also floppy disks, they are also floppy disks
Hard disk drives (HDD), they are also 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.
Some time ago, floppy disks were the most popular means of transferring information from computer to computer, since the Internet was very rare in those days, computer networks too, and CD-ROM drives were very expensive. Floppy disks are still used today, but they are already quite rare. Mainly for storing various keys (for example, when working with the client-bank system) and for transmitting various reporting information to state supervisory services.
Diskette- portable magnetic storage medium used for multiple recording and storage of data of a relatively small volume.
This type of media was especially common in the 1970s and early 2000s. Instead of the term "floppy disk", the abbreviation HMD is sometimes used - "floppy disk" (accordingly, the device for working with floppies is called floppy disk drive - "floppy disk drive", the slang version is a flop drive, flopik, flopar from the English floppy-disk or in general cookie "). Typically, a floppy disk is a flexible plastic plate covered with a ferromagnetic layer, hence the English name "floppy disk". This plate is housed in a plastic case that protects the magnetic layer from physical damage. The casing is flexible or durable. Floppy disks are written and read using a special device - a floppy drive. A floppy disk usually has a write protection feature, through which you can provide read-only access to data. Appearance 3.5 ”floppy disk is shown in fig. 1.2.