Used for long-term storage of information and transmission. Long archival storage of data, or how to see the selfie of my great-grandmother? Use optical discs

Test "Computer Device"

The task : carefully read the question, then select the right answer options, the answer can be only one.

Question 1. Computer is -

device for processing analog signals;

device for storing information of any kind.

multifunctional electronic device for working with information;

electronic computing device for treating numbers;

Question 2. Computer performance (speed of operations) depends on:

processor clock frequency;

the volume of processed information.

speed pressing keys;

monitor screen size;

Question 3. The system of interrelated technical devices that perform input, storage, processing and output is called:

1. Software;

2. Computer support;

3. Hardware.

4. Systems;

Question 4. Device for visual reproduction of symbolic and graphic information -

1. Processor;

2. Keyboard.

3. Scanner;

4. Monitor;

Question 5. What device is not in the system unit?

1. Video card;

2. Processor;

3. Scanner;

4. Hard disk;

5. Network card;

Question 6. Drive is a device for

1. Read / write data from external media;

2. Storage of commands of the executable program.

3. Long-term storage of information;

4. Processing the commands of the executable program;

Question 7. What device is not peripheral?

1. Hard disk;

2. Printer;

3. Scanner.

5. WEB-camera;

Question 8. A printer with an ink print head, which under pressure throws ink from a row of the smallest holes on paper, is called

1. sublimation;

2. Matrix.

3. inkjet;

4. Hard;

5. Laser;

Question 9. The program is a sequence ...

1. Commands for a computer;

2. electrical impulses;

3. zeros and units;

4. Text signs;

Question 10. When the computer is turned off, all information is lost ...

1. on a flexible disk;

2. on the hard disk;

3. on the CD-ROM disk;

4. In RAM;

Question 11. For long-term storage of user information, serves:

1. External memory;

2. Processor;

3. Drive;

4. RAM;

Question 12. Before disconnecting the computer, information can be saved:

1. In RAM;

2. in external memory;

3. in processor registers;

4. On the drive;

Question 13. The smallest addressable part of the computer's memory:

4. Machine word;

Question 14. Magnetic disk is intended for:

1. Information processing;

2. Storage of information;

3. Input information;

4. Informance of information;

Question 15. Where is the program being performed at the moment and the data being processed?

1. in external memory;

2. in RAM;

3. in the processor;

4. On the input device;

Question 16. The CD for multiple records of the new information is called:

Question 17. The program is ...

1. Processed information provided in the computer's memory in a special form;

2. Electronic circuit, managing the operation of the external device;

3. A description of the sequence of actions that the computer must perform to solve the data processing task;

4. Software controlled device for performing any types of working with information;

Question 18. Information is called data if it is represented ...

1. In the form of text from the textbook;

2. in numerical form;

3. in binary computer code;

4. In the form of commands for the computer.

Explanatory note

Studying the course "Informatics and ICT", we met with one of the sections "Information and Information Processes". After that, having read, with this section, we found out that information processes in the lives of people and societies, in nature and technology are the same in nature and are reduced to four main processes: the collection, storage, transformation and transmission, which are these actions committed on information. and occur using a computer. In the "Computer Device" section, we studied the computer's work scheme (principles of background-neimane), the main modular principle of building a computer, computer device. The study of the section is completed.

The purpose of the test work through the test method is determined by identifying the level of knowledge and skills of students of 8 classes by section "Computer Device".

1. Reselect the level of formation of students' knowledge of grade 9 by section.

2. Develop skill to work independently without support on the theoretical position of the textbook, using its knowledge.

3. Rift collaboration and accuracy when performing test work.

For each correct answer, one score is assigned, in the amount you need to dial 18 points. The evaluation of test work will be calculated in the percentage ratio, where:

100% - 95% (18-17 points) - Marker "5"

94% - 75% (16-13 points) - Mark "4"

74% - 51% (12-9 points) - Mark "3"

less than 50% (less than 9 points) is the "2" mark with the subsequent relocation, but the final mark will be on the score below.

Key to test test

External memory is used for long-term storage of information solid media storage drives on rigid magnetic disks (HDD, HDD) hardware implementation of magnetic tape drives - "Streamers" drives on laser disks (CD, Compact Disk, etc.) Media information - Wednesday Recording / reading and storing information.

Option classification of media used in computer technician Media information for computer Ribbon media Magnetic disk carriers Optical Flash carriers Magneto optical

The main type of external memory is the magnetic memory Magnetic recording at the end of 1898 Dane Valdemar Polesen (Valdemar Poulsen) suggested a device for a magnetic sound recording on steel wire. After 30 years, the German engineer Fritz Pleimer (Fritz Pfleumer) presented a sound recording device with a carrier in the form of a paper tape, which caused a thin steel coating. In 1932, the German company AEG demonstrated the first recording apparatus, which was called "Magnetophon". The magnetic tape has the main disadvantage - the ability to demagnetize during long-term storage and has an uneven frequency response (different sensitivity to record at different frequencies). In addition, any magnetic tape has its own noise (the physical properties of the magnetic layer and the methods of recording-play sound).

The principle of the magnetic record consists in the effects of the electromagnetic field on the ferromagnetic material of the magnetic tape, carried out when recording, as well as overwriting an analog signal. The magnetic field in the recording process varies in accordance with the changes in the electrical signals. Electrical oscillations from the sound source are fed to the recording head and excit the magnetic field of the sound frequency (20 Hz - 20 k. Hz). Under the action of this field, there is a magnetization of individual sections of the magnetic tape, evenly moved along the recording heads, erasing and playback (Fig.).

To record playback, as well as the use of various data on computer-readable data media, use analog (sound and video) signal to digital form. Such a technology was named the digitization of information. The principle of digitization (encoding) of the sound is to convert continuous different over the amplitude of the amplitude audio and video signals into the encoded sequence of numbers representing the discrete values \u200b\u200bof the amplitudes of this signal, taken after a certain period of time. To do this, it is necessary to measure the amplitude of the signal at certain intervals and at each time of the segment to determine the average amplitude of the signal. According to the Shanon Theorem (Kotelnikov), this period of time (frequency) should be at least double the maximum frequency of transmitted sound signal (Fig.).

This frequency is called the sampling frequency. Discretization is the process of taking the references of the signal continuous in time in equivalent from each other by the time of points constituting the sampling interval. During the sampling process, the level of analog signal is measured and remembered. Amplitude frequency (Hz) Fig. 13. Convert analog signal into digital. The less often (less) time intervals, the quality of the encoded signal is higher.

Streamers Tape media are used to back up in order to ensure the safety of data. As such devices, a streamer is used (Fig.), And the carrier of information in them is used magnetic tapes in cassettes and tape cartridges. Usually, the recording is carried out to the magnetic tape, while the domain corresponds to a binary unit. If the reader does not detect it, the value obtained corresponds to zero.

The record system for magnetic discs and diskettes are somewhat similar to the record of the record on the record. Unlike the latter, the record is not carried out on the helix, but on the concentric circles - tracks ("Tracts" - Traks) located on two sides of the disk and forming cylinders. Circle, in turn, are divided into sectors (Fig.). Each floppy sector, regardless of the size of the track, has the same size equal to 512 bytes, which is achieved by different recording density: less peripherals and more closer to the center of the floppy disk.

Magneto optical information carrier External high-spirits and storage devices. Magneto-optical disks (MO) appeared in 1988. The monitor is enclosed in a plastic envelope (cartridge) and is an arbitrary access device. It combines the magnetic and optical principles of storage of information and represents a polycarbonate substrate (layer) with a thickness of 1, 2 mm, which causes several thin-film magnetic layers (Fig.). Recording a laser with a temperature of about 200 o. The magnetic layer occurs simultaneously with the change in the magnetic field. Fig. The composition of the Disk.

Data recording is carried out by a laser in a magnetic layer. Under the influence of temperature at the heating site in the magnetic layer, the resistance to the change in polarity is reduced, and the magnetic field changes the polarity at a heated point to the corresponding binary unit. At the end of heating, the resistance increases, but the installed polarity is preserved. Erasing creates the same polarity in a magnetic field corresponding to binary zeros. In this case, the laser beam consistently heats the washed plot. Reading recorded data into the layer is produced by a laser with a smaller intensity that does not lead to the heating of the readable area. At the same time, in contrast to CDs, the disc surface is not deformed.

Compact optical disk (CD) is a plastic disk with a special coating on which recorded information is in digital form. Due to the change in the speed of its rotation, the track relative to the reading beam of the laser moves with a constant linear speed. At the center of the disk the speed is higher, and the edge is slower (1, 2- 1, 4 m / s). The CD use a laser with a radiation wavelength \u003d 0, 78 microns. The "burnable" laser digital information is preserved in the form of "pit" - cigroxks width 0, 6-0, 8 μm and a length of 0, 9-3, 3 μm. There are three main types of CD: ● CD-ROM to which the entry, as a rule, is carried out by the factory method of stamping from the matrix; ● CD-Rs used for one or non-slip laser recording sessions; ● CD-RW intended for multiple recording cycles.

In the CD-R (Compact Disk Recordable) on top of the reflective layer of gold, silver or aluminum, there is an organic layer of special light-melting plastic. In view of this, such a disk is sensitive to heating and exposure to direct sunlight. In CD-RW, an organic composition is also used as an intermediate layer, but it is capable of moving from a crystalline (transparent for laser) in amorphous with a strong heating. Weak heating returns it back to the crystalline state. Thus, overwriting is carried out.

DVD In early 1997, a CD standard called DVD (Digital Video Disc) appeared, designed mainly to record high-quality video programs. In the future, the DVD abbreviation received the following value - Digital Versatile Disc (universal digital disc), as more fully meets the capabilities of these disks to record sound, video, textual information, software PC and other DVD provides more high quality Images than CD. They use a laser with a shorter radiation wavelength \u003d 0, 635-0, 66 μm. This allows you to increase the record density, i.e. reduce the geometric sizes of PIT up to 0, 15 μm and the pathway up to 0, 74 μm.

The density of the optical disc recording is determined by the laser wavelength length, that is, the possibility to focus on the disc surface of the beam with a stain, the diameter of which is equal to the wavelength. Following the DVD, at the end of 2001, Blu-ray devices appeared, allowing to operate in the blue region of the spectrum with a wavelength \u003d 450-400 nm.

Fluorescent Multilayer Disk (Fluorescent Multilayer Disk) is used to increase the tank. The principle of their action consisting in changing the physical properties (the appearance of fluorescent luminescence) of some chemicals under the influence of the laser beam (Fig.). Here, instead of CD and DVD technologies using a reflected signal, the light is lowered by the light to the laser, the light is emulsioned. Such discs are made of transparent photochromas. Under the influence of laser radiation, they include a chemical reaction, and individual sections of the information layer ("Petes") are filled with fluorescent material. This method can be considered by the method of data recording. In the greater degree, such a record is possible when using three-dimensional holography, which is now in a crystal size with a sugar cube, to accommodate up to 1 TB of data.

Two main types of Flash memory are used: NAND and NOR (logical or-no) and Nand (logical function and non). The NOR structure consists of parallel enabled elementary storage cells. Such the organization of the cells provides random access to the data and the delete record of information. The NAND structure is based on the principle of a serial connection of elementary cells forming groups (16 cells in one group), which are combined into pages, and pages in blocks. With such a construction array, an appeal to individual cells is impossible. Programming is performed simultaneously only within one page, and when erasing, the circulation occurs to blocks or block groups.

NOR chips work well jointly with RAM RAM, so more often used for BIOS. When working with relatively big arrays Data Recording / Erasing Processes The NAND memory is performed much faster than in the NOR memory. Since the 16 adjacent Nand memory cells are connected in series, without contact gaps, a high density of cell location on a crystal is achieved, which makes it possible to obtain a large container with the same technological standards. From the mid-1990s. NAND microcircuits appeared in the form of solid-state disks (SOLID STATE DISK, SSD). To compare the access time in the SDRAM it is 10-50 μs, the flash memory is 50-100 μs, and hard disks - 5000 - 10,000 μs.

Salted Samsung hard drive. The speed of reading from such a disc is 57 MB / s, and the recording speed is 32 MB / s. SSD power consumption is less than 5% of the indicators of traditional hard drives, increasing by more than 10% of the battery life of the portable PC. SSD provide ultra-high reliability of data storage and have proven itself in extreme temperatures and humidity conditions. Petersburg firm "Just. Soft "offered Flash driver. RAID to combine two flash drives in a RAID array.

Flash memory is a portable non-volatile drive. The following Flash Memory Standards are commonly used: Compact. Flash, Smart. Media, Memory Stick, Floppy disks, Multi. Media Cards, etc. They can be used instead of floppy disk, laser and magneto-optical compact, small hard drives. Modern interchangeable flash memory devices provide high data exchange rate (Ultra High Speed) - more than 16, 5 Mbps. To connect to the USB port of the computer, special USB Flash. DRIVE (Fig.), Which are mobile small-sized storage devices that do not have mobile and rotating mechanical parts.

Holography is a photographic method of recording, playback and conversion of wave fields. For the first time he was proposed in 1947 by the Hungarian physicist Dennis Gabor. In 1960, with the advent of the laser, it was possible to accurately record and reproduce the volume images in the Lithium Niobate crystal. Since the 1980s, with the advent of CDs, holographic information storage devices based on laser optics have become one of the external memory technologies. Holographic memory represents the entire volume of storage medium of the medium, and the data elements accumulate and read in parallel.

Modern holographic storage devices were called HDSS (Holographic Data Storage System). They contain: laser, beam discriminator for separating a laser beam, mirrors for the direction of laser rays, a liquid crystal panel used as a spatial light modulator, lenses for focusing laser rays, a lithium niobate crystal or a photopolymer as a storage device, a photodetector for reading information (Fig.) .

Each user has information that I would like to preserve for a long time. Photo, video, audio or important documents. However, just write them on the hard disk and not touching enough. Gradually, the drive is worn out, besides, do not forget about failures or damage. This article will describe how to properly store information for better safety.

General Principles of Safe Storage of Information

Need to do multiple copies. Really important files are better to write on several devices or drives, which will most likely be preserved at least one carrier in case of unforeseen circumstances.
Data is better to store in widespread and famous formats. If this is a text document, it is better to preserve it in a TXT format than in some exotic. The likelihood that after a dozen years there will be programs capable of opening the most common format much higher than if it is a file that is capable of running only a pair of utilities.
The more the data is the better. Do not encrypt, Archive or compress data. In the case of a small damage of the usual file, there are good chances of starting it, and in case of damage to the archived or encrypted chances of small.
Also do not forget check your data From time to time, if the carrier is many years or there is doubts about its integrity, it will be better to recover information to a new drive, also a good idea to use new devices and record types.

The use of traditional drives

This section will describe the standard storage options, as well as the advantages and disadvantages of each of them.

CD, DVD, Blu-ray Theoretically, these drives are capable of being stored for a very long time, as well as information on them. However, there are many nuances here, so this method will be considered in more detail below.
Cloud storage. These data can be stored indefinitely for a long time. This is in the perfect world. In fact, they will be there to be beneficial to companies and benefit them. In addition, judging by licensing agreements, no responsibility for saving information they do not bear. In addition, the user can simply forget the password or can hack it. So there is no guarantee that this information will be saved more reliable than the usual hard disk.

Use optical discs

This method is the most reliable in terms of durability, some manufacturers call deadlines almost one hundred years. However, many have come across such a situation that the Dwarc can not be read not that in a couple of years, but even in a few months. There are several reasons for it.

What to pay attention to when choosing a disk

The materials of which reflective and recorded layers are very important in the discs, as well as the other parts of the disk.

The recorded layer ideally should consist of phthalocyaninand reflective layer of gold or silver. Although manufacturers may choose another combination of substances. In addition, users such fineness are not needed. All you need to know is that disks for long-term storage of data have in their name sending to archives or directly called archival, for example, DVD-R Mitsui Mam-A Gold Archival or Verbatim UltraLife Gold Archival. They stand much more expensive and find them in stores are unlikely to be able to be ordered in other countries. In addition, they are much more expensive than ordinary discs, but they store information longer, up to 100 years.

From the available options can be purchased Verbatim. or SonyMade in Taiwan.

The following is a diagram that displays the number of errors of reading information from the disk, depending on the time spent in the aggressive environment.

MILLENNIATA M-DISK

As can be seen from the schedule, this company produces some of the most reliable disks. In fact, most of the differences consists in the material and method of recording. On these carriers is not organic, but glass carbon layer To record information.

At the same time, instead of changing the color, as is done when recording conventional optical drives, the material burns here in the literal sense.

This allows data to be stored much longer, and they are less dependent on external factors. You can find many rollers on the Internet, in which these disks are mocked as they can, and they continue to work. So, if the information really will be stored for a long time, it is worth thinking about the purchase of discs of this manufacturer.

Reliable storage of information is a problem, familiar to the majority of modern enterprises, when resolving which the question always fails: how at relatively low costs get a quality result? Storage of documentation B. in electronic format It provides not only its safety, but also unimpeded availability in real time.

For long-term and reliable storage of archival information in electronic form, various types of information carriers are applied. The main requirement for such media is the elimination of the ability to physically make changes to archive data or delete them. The information carrier must provide a single record and at the same time be able to repeat the information. This requirements correspond to the WRITE ONCE-WRITE ONCE type information medium, read Many (write it once, take it many times). On other basic requirements for information carriers include durability and maximum storage capacity of archival data.

Hard drives.

The use of hard drives allows you to organize the so-called "operational" storage of archival data, which provides permanent on-line access to archival documents. The kernel of such a storage is a multi-level archive storage architecture in which frequently requested archival data are stored on "fast" hard drives with external interface FIBRE CHANNEL (FC) or Serial Attached SCSI (SAS), and rarely requested archive data are stored on "slow" hard drives with the external Serial ATA interface (SATA) and NL-SAS.

There is an opinion that backup systems are a burden for IT budget, and for IT units, so to speak, excess headache. But ... Manufacturers of data storage systems (storage) on rigid disks of all levels, it is still recommended to use as part of such solutions of a backup system for tape carriers, with which a copy of the data is created, from which, in case of refusal to the performance of the storage, can be restored data.

Ribbon carriers.

The main purpose of tape carriers is to create backup copies of operational data (Backup). Based on tape carriers, you can also organize archival storage of information. Solutions on tape media provide non-oroderative (Near-Line) access to archive information. The basis of such a solution is a robotic drive on tape carriers. To date, the storage volumes on the same belt medium in LTO-5 format is 1.5 TB (3 TB with the ability to compression data). Therefore, storage systems on ribbon media are used to reliably storing information large volumes of archival data. These solutions have a number of serious flaws. Ribbons are demaging, ruting, you need to constantly rewind the tape in the cartridges, a long time is spent on the search for a specific file until the tape is rewound in the cartridge to the desired location, the disadvantage of the media is forcing periodically to transfer data from the old tape to a new ribbon. When organizing off-line storage, archival data cartridges must be stored in rooms with certain environmental requirements or in specialized cabinets.

Optical media.

To organize long-term storage of archival data, you must use drives on optical disks. Such drives ensure that all the requirements for archival repository and storage of archival data are fulfilled. High reliability long deadlines Storage of archival data, contactless work with carriers, authenticity and unchanged archival data, quick arbitrary access to archival data, high capacity optical media, organization of off-line storage of archival data are important parameters when choosing optical media.

To date, the most popular format for recording to the optical medium is a Blu-ray format that provides a high archiving density up to 100 GB per optical medium. Worm support on the hardware level allows you to store recorded on optical media, archived data that is subsequently unable to delete or change. A "Open" Recording format of the UDF record allows you to read archive information in any device that supports work with such optical media. The main task is to store rarely requested and not changeable archival data. Practice shows that the volume of such data is about 80% of the total data stored on the operational (on-line) repository. At the same time, 20% of these archival data will never be in demand. By sending such data to the archive storage based on optical media, the customer can free up to 80% of the storage volume on the operational (on-line) storage, which will result in the reduction of the volume and sizes of the backup window.

Solutions on optical media provide non-orode (Near-Line) access to archive information. The storage volume of archival data in the optical media drive and the number of read devices is determined according to the technical task. Different types of archival decisions are supported, up to "mirroring" of archival data between geographically distributed drives on optical media. Contactless operation with optical media makes it possible to eliminate the possibility of damage to the working surfaces of optical media. Reference compatibility with previous types of optical media types CD \\ DVD is provided. When organizing archive storage data based on the optical media, you do not need to create backups This data.

Advantages and disadvantages

Hard drives

Operational access to archive information
Arbitrary access to archive information
Popularity Solutions
High power consumption
Dorganiza solution
It is required to create backup copies of archive data.
Minimum "deadlines" of life (maximum 3 years)
When the mechanical part of the hard disk fails, the data to restore is almost impossible
Not intended to organize off-line storage

Ribbon carriers

Large storage of archival data
High speed recording information on tape carriers
Low power consumption
High cumulative cost of ownership
Minimum "deadlines" of life (on average up to 5 years)
"Closed" format for recording information on tape carriers
Low reading time (minimum 5 min)
Loss of information when exposed to electromagnetic radiation
The possibility of mechanical damage (tape break)

Optical carriers

Non-volatility of optical carriers
Storage time of archival information from 50 years
Support Worm function at the hardware level (unchanged archival data)
Ability to organize off-line storage of archival data
"Open" recording format (UDF) on optical media
Low cumulative cost of ownership
Low electricity consumption

Conclusion

Most specialists in building archival decisions agree that in order to archive storage of information with the possibility of prompt access to it, it is best to apply a multi-level archival storage structure. The main criterion in choosing a solution should not be cheap, and the conservation and protection mechanism of archival data, which is implemented in this decision. Before making the final choice, you need to check all the equipment and software for compatibility.

COURSE WORK

in the discipline "Informatics"

Long-term storage devices

Introduction

1. Basic concepts

2. Classification of long-term storage devices

3. Detailed characteristics of devices of long-term storage of information

3.2 Optical disks

3.3 Flash Memory

4. Practical part

Conclusion

Bibliography

Introduction

In information storage computers allocate the following main types of memory: internal memory, cache memory and external memory. In addition, various specialized types of memory may be present in EUM characteristic of certain computing system devices, such as video memory.

In the theoretical part of this term paper Devices of long-term storage of information will be considered. Such devices relate to the external memory of the computer and allow you to save information for subsequent use regardless of whether the computer is turned on or off.

Modern society is characterized by the intensive development of technical and software. Based on timely replenishment, accumulation, recycling of the information resource, rational management is possible and the adoption of certain solutions. This is especially important for the sector of the economy. Permanent growth of information flows places increased requirements for the application of storage devices. In this regard, the consideration of the issue concerning the means of long-term storage of information is very relevant.

This topic will be disclosed using the following questions:

1. Basic concepts;

2. Classification of devices of long-term storage of information;

3. Detailed characteristics of devices of long-term storage of information.

In the practical part of the course work, the task will be solved:

The organization includes a magazine calculation of income tax with employee wages from the point of view of divisions. Types of divisions are presented in Fig. 1. At the same time, the following rule works:

All deductions are provided according to the table (Fig. 2) Only the employees of the "main" job place, the remaining workers pay tax with the total amount.

This term paper was performed on an IBM standard configuration PC, including a system unit, monitor, keyboard, mouse with the following characteristics: 64-bit microprocessor AMDATHLONIIX3 3.0 GHz, RAM 8192 MB, NVIDIAGEGFORCEGTX 550 TI video card, 1024 MB, WD hard drive with volume 2 TB, DVD-RWNEC, LG 22 monitor with a resolution of 1920x1080. The work was carried out in Windows 7 maximum using text editor Microsoft Office. Word 2010, tabular microsoft processor Office Excel 2010 included in the integrated PPP Microsoft Office 2010 Professional Plus.

Introduction

Information storage devices (external memory) are computer components that allow virtually unlimited time to maintain large amounts of information without electricity consumption (non-volatile).

The first such devices for PCs were floppy drives (FDD) and replaceable floppy disks - at the beginning of the five-year (5.25 ") capacity of 360 KB and 1.2 MB, then three-tie (3.5") capacity of 1, 44 MB. Currently, it is rarely applied due to the wide distribution of flash memory devices with a container of several gigabytes.

A characteristic feature of the external memory is that its devices operate with blocks of information, but not by bytes or words, as whether the RAM allows. These blocks usually have a fixed size, multiple degree of number 2. The block can be rewritten from the internal memory into external or back only entirely, and to perform any external memory exchange operation requires a special procedure (subroutine). Exchange procedures with external memory devices are tied to the device type, its controller and method of connecting the device to the system (interface).

External memory is used to long-term storage of large amounts of information. In modern computer systems as external memory devices, the most commonly applied:

* Storage devices on hard magnetic disks (NGMD)

* Drives on flexible magnetic disks (NGMD)

* Drives on optical disks

* Magneto optical media.

1. Basic concepts

External memory is the memory implemented in the form of external motherboard, devices with different storage principles and media types intended for long-term storage of information. In particular, all computer software is stored in the external memory. The external memory devices can be placed both in the computer's system unit and in separate cases. Physically, the external memory is implemented in the form of drives.

Drives are storage devices intended for long (which does not depend on power) storage of large amounts of information. The capacity of the drives hundreds of times the capacity of RAM or is generally unlimited when it comes to drives with interchangeable media.

The carrier is a physical storage environment, in appearance can be disk or tape. According to the principle of memorization, magnetic, optical and magneto-optical media differ. Ribbon carriers can only be magnetic, in disk carriers use magnetic, magneto-optical and optical methods for recording-reading information.

2. Classification of long-term storage devices

As information storage devices, external memory are used, which are implemented in the form of relevant technical means for storing information. All drives used in PCs are unified in constructive execution. Their sizes are standardized: the width and height of the devices are most rigid, the depth is limited only to the maximum allowable value. Such standardization is necessary for the unification of structural compartments of PC cases.

External memory can be with arbitrary access and consistent access. Random Access Memory Devices allow you to access an arbitrary data block in approximately the same access time. Memory devices with allegant access allow access to data sequentially, i.e. In order to read the desired memory block, you need to consider all previous blocks.

Allocate the following main types of memory devices:

1. Hard magnetic drives (Winchesters, HDD) - non-removable hard magnetic discs. They refer to external memory with direct access to data and are divided into internal, installed in the system block of the computer and external (portable) relative to the system unit.

2. Drives on flexible magnetic disks (floppy drives, NGMD) - devices for recording and reading information from small removable magnetic disks (floppy disks) packed in a plastic envelope (flexible - 5.25 inch diskettes and hard 3.5 inch ). Reference to external memory with direct (arbitrary) access to data stored on a magnetic disk and are intended for long-term storage relative to small amounts of information.

3. Information drives on optical disks are external (arbitrary) access to the data and are intended for long-term storage of relatively large amounts of information (hundreds of megabytes and tens of gigabytes).

4. Flash-memory-based information storage devices refer to external memory with direct (arbitrary) data access and are intended for long-term storage relative to small amounts of information (gigabyte units).

5. Magnetic tape drives (NML) - data reading devices from magnetic ribbons, which belong to external memory with sequential access. Such drives are sufficiently slow, albeit a large tank. Modern devices for working with magnetic ribbons - streamers - have an increased recording speed of 4-5 MB in sec. There are also devices allowing you to record digital information on video tapes, which allows you to store on 1 magazine 2 GB of information. Magnetic ribbons are usually used to create data archives for long-term storage of information.

6. Perfoocards - Dense paper cards and Perflectors - Coils with a paper tape, in which the information is encoded by penetrating (perforation) holes. Sequential access devices are used to read the data.

Currently, devices with sequential access to the NGMD data are morally outdated and do not apply, therefore we will not consider them in detail.

3. Detailed characteristics of devices of long-term storage of information

3.1 Hard magnetic drive drives

Fig. 1 Hard Drive (Winchester)

Drive on hard magnetic disks, or hard drive is an energy-dependent, rewritable computer storage device. The data stored on the hard disk is not lost when the computer is turned off, which makes the hard drive ideal for long-term storage of programs and data files, as well as the most important programs. operating system (OS). This its ability allows you to get a hard drive from one computer and insert to another.

Inside the sealed hard disk there are one or more unbending disks covered with metal particles. Each disk has a head (electromagnet), built into the hinge lever, which moves above the disk during its rotation. The head magnetizes metal particles, forcing them to line up for the appearance of zeros and units of binary numbers (Fig. 1). Motors, moving disk and lever, are usually deposited. Avoid wear manifest only the head, since it never comes into contact with the surface of the disk.

The name "Winchester" received the drive thanks to the company IBM, which in 1973 released a hard disk of the model 3340, which first combined the disc plate and reading heads in one unintended body. When developing it, engineers used the brief internal name "30-30", which meant two modules (in the maximum layout) of 30 MB each. Kenneth Hoton, Project Manager, on Winchester 30-30, with the designation of the popular hunting rifle "Winchester 30-30" suggested calling this drive "Winchester".

Before using new hard drives need to format. This process is in laying magnetic concentric tracks and in their breakdown to small sectors, like pieces in the cake. But if data was recorded on the hard disk, its formatting will result in their full destruction.

Due to the larger number of paths on each side of the disks and a large number of disks, the hard disk information capacity can reach 150-200 GB. The recording speed and reading of information from hard drives is large enough (can reach 133 MB / s) due to speed rotation of the disks (up to 7500 revolutions / min).

Other parameters note:

1) Cache-memory capacity - in all modern disk drives, a cache buffer is installed, accelerating data exchange; The more its capacity, the higher the likelihood that in the cache memory will be the necessary information that does not need to be read from the disk (this process is thousands of times slower); Cache buffer capacitance in different devices It may vary within the borders from 64 KB to 2 MB;

2) The average access time is the time (in milliseconds), during which the head block is shifted from one cylinder to another. Depends on the design of the drive of the heads and is approximately 10-13 ms;

3) the delay time is the time from the moment of positioning the head block to the desired cylinder before positioning the specific head to the specific sector, in other words, is the time of searching for the desired sector;

4) exchange rate - determines the amounts of data that can be transmitted from the drive to the microprocessor and in the opposite direction for certain intervals; The maximum value of this parameter is equal to the bandwidth of the disk interface and depends on which mode is used.

IN hard disks It uses sufficiently fragile and miniature elements (carrier plates, magnetic heads, etc.), therefore, in order to save information and working capacity, hard drives must be protected from shocks and sharp changes in spatial orientation during operation.

Class 7200 / 3.5 Disk Market Leaders, CompaniesSeagate, Maxtor and WWD, also produce external hard drives, made in a separate case with a power supply, USB orIEEEE1394 interface (FireWire).

Hard disk, regardless of the presence or absence of a drive for flexible disks, is always customary called "C".

3.2 Optical disks

In addition to drives for working with flexible discs personal computers Usually include devices for working with optical (laser) discs, which have a diameter of 5.25 inches (133 mm).

CD-ROM drive

Fig. 3. CD

In 1995, the first optical disk drive appeared in the PC basic configuration - CD-ROM (COMPACTDiskReadonlyMemory, a constant storage device of CDs) (Fig. 2). The device used multi-layer CDs with a diameter of 120 mm and a thickness of 1.2 mm, the capacity of the disk 650-700 MB.

The CD consists of 4 layers (top-down):

2) layer for record information;

3) reflective layer;

4) base of polycarbonate.

The process of making a disc consists of operations by spraying silver or gold of a reflective layer to the base, applying a transparent layer to it for recording information and squeezing on it of recesses forming a spiral track, running from the center of the disk to its edge. For disk stamping, the prototype matrix (master disc) of the future disk is used. After that, a protective layer of transparent plastic is applied to the surface of the disk.

CD-ROM reads information from a disk using a laser beam with a wavelength of 780 nm, which is different from the surface of the disk (Land) and recesses on the surface (PIT). The minimum size of the pit is 0.88 microns, the step of the tracks is 1.5 microns.

The main characteristics of CD-ROM:

1) the data transfer rate - is measured in multiple shares of the speed of the audio CD player and characterizes the maximum speed with which the drive forwards data into the computer's operational memory;

2) Access time - the time required to search for information on the disk is measured in milliseconds.

CD-RW Drive

The device is used to record information on CD-R discs (once record) and CD-RW (CD-Rewritable - rewritable disk).

Externally, it looks like a CD-ROM and compatible with it to the size of the disks and recording formats. Data recording is carried out using special software or operating system.

CD-R or CD-RW has 4 layers (top-down):

1) a protective layer of polycarbonate;

2) an active layer for recording information;

3) reflective layer;

4) base of polycarbonate.

DVD-ROM drive

Further development of CD making technologies led to the creation of high-density discs, which were called digital universal disks (DVD - Digital Versatile Disk). In such disks, a spiral track of recording - reading data with reduced gaps between adjacent turns is used. In addition, the depressions and protrusions have a smaller size compared to CDs. This made it possible to increase the amount of information on the disk to 4.7 GB.

According to the DVD data structure, there are:

§ DVD-Video (read-only) - contain movies (video, sound);

§ DVD-AUDIO - contain audio data high quality;

§ DVD-DATA - contain any data.

How do DVD media happen:

§ DVD-ROM drives made by injection molding (casting under pressure from durable polycarbonate plastic);

§ DVD-R - Operating Discs - the format developed by Pioneer. The technology of the record is similar to CD-R and is based on an irreversible change under the influence of the laser of the spectral characteristics of the information layer, covered with a special organic composition. DVD-R discs can be recorded both computer data, multimedia programs and video, audio information;

§ DVD + RW - multiple wheels (RW - Rewritable) entries. On DVD + RW drives, both video and sound and computer data are recorded. DVD + RW discs can be overwritten about 1000 times;

§ DVD-RW - multiple recording format developed by Pioneer. DVD-RW discs contain 4.7 GB to one side, are available in one-sided and double-sided modifications and can be used to store video, audio and other data. DVD-RW discs can be overwritten up to 1000 times and are read on the first generation DVD-ROM drives;

§ DVD-RAM - repeated recording wheels (RAM - RandomaccessMemory) - format developed by Panasonic, Hitachi, Toshiba. First generation dVD disks-Ram accompanied 2.6 GB to the side. Modern - second-generation discs are 4.7 GB on the side or 9.4 GB for bilateral modification. The most important advantages of DVD-RAM disks are overwriting up to 100,000 times, the presence of a recording error correction mechanism.

Blu-ray and HD drives

In 2002, representatives of nine leading high-tech companies Sony, Panasonic, Samsung, LG, Philips, Thomson, Hitachi, SharPioneer at a joint press conference announced the creation and promotion of a new high-capacity optical disk format called Blu-Raydisk - a rewritable disc next generation Standard CD / DVD size 12 cm with maximum capacity records per layer and one side up to 27 GB.

The HDDVD format was proposed by TOSHIBA and NEC at the 2003 DVD Forum session. In February 2008, it became known about the actual victory of Blu-Raynad HDDVD: Toshiba reported on full folding of work in this direction. The production of films and other programs on HDDVD also stopped.

TechnologyBlu-RayyHD was created primarily for recording, storing and playing video and audio information, however, these discs can be recorded and simply data. Blu-ray format involves working with a resolution video stream up to 1080p, sound up to 7.1 and support for HDCP information protection protocol. Video coding algorithms - MPEG-2 HD, VC1 (Video Codec 1, based on Windows Media Video 9) and H.264 / MPEG-4 AVC, sound formats - AC3, MPEG1, MPEG Layer 2. For digital video players of Blu- format Raydecoding will be done hardware for computer drives - software.

Blu-ray devices have high data transfer speeds. According to the specification, the maximum data transfer rate between Blu-ray drive and the target device can reach 36 Mbps.

3.3 Flash Memory

Fig. 3. Flash memory

computer information memory disc

Flash memory has appeared for a long time (the first samples were developed by Toshiba back in 1984), but its mass use began with the wide distribution of digital cameras. Today manufacturers produce flash memory of several types:

§ Flash cards (Fig. 3) Compact Flash (CF), Smart Media (SM), Multi Media Card (MMC), Secure Digital (SD), Memory Stick Pro (MSPRO), Memory Stick (MS) and XD-Picture (XD) - To work with them, you need a flash card reader;

§ USB flash memory self-sufficient and does not require applications additional devices To record and read information, has a connector for connecting to the USB port of the PC.

Flash memory is a type of esappa, its full name Flash Erase Eeprom (Electronically Erasable Programmable ROM) can be translated as "quickly electrically erasable programmable constant memory." In other words, the flash memory is an energy-dependent (not consuming energy when storing data) overwritten memory, the contents of which can be quickly erased.

As a high-speed and universal storage device for transferring a sufficiently large amount of data, it is convenient to use USB flash memory.

4. Practical part

General characteristic of the task

The organization includes a magazine calculation of income tax with employee wages from the point of view of divisions. Types of divisions are presented in Fig. 4. At the same time, the following rule works:

All deductions are provided according to the table (Fig. 5) only employees of the "main" job place, the remaining workers pay tax with the total amount.

1. Build tables according to the data below (Fig. 4-6).

2. Organize interstabilities to automatically fill the graph of the document "Log for calculating income tax individuals (NDFL) "" Name of the division "," NDFL "(Fig. 6).

3. Configure the check in the "Opening Place" field on the entered values \u200b\u200bwith the error message output.

4. Determine the monthly amount of the tax paid by an employee (in a few months).

5. Determine the total amount of personal income PFFs for each subdivision.

6. Determine the overall listed Ndfl amount listed in the month.

7. Build a histogram according to the summary table.

Fig. 4 List of organization divisions

Fig. 5. Betting benefits and taxes

Fig. 6 Table data of the magazine calculation of income from individuals

The solution of the problem

1. Run the MSExcel tabular processor.

2. Sheet 1 Rename into a sheet with the name "Division".

3. On the work sheet of the "division" we create a table of the list of units of the organization (Fig. 7).

Fig. 7. Location of the table "List of units of the organization" on the work sheet "Divisions" Msexcel

4. Sheet 2 rename to a sheet with the name of the bet, on which we create a table of "betting and taxes" table and fill it according to the condition (Fig. 8).

Fig. 8 Location of the table "Betting and taxes" on the work sheet MSEXCEL rates

5. Sheet 3 rename to a sheet with the name of NFFL, on which we create a table "The magazine calculation of income from individuals" and fill it with the source data (Fig. 9).

Fig. 9 Location of the Table "Magazine Calculation of Revenues from Individuals" on the work sheet of the NDFL MSEXCEL

6. We organize interstabilities to automatically fill in the Count of the Magazine Calculation of income from individuals: "Name of the Unit", "NDFL".

To do this, fill the Count the name of the division of the table "The magazine for calculating income tax from individuals", located on a list of NDFL as follows:

We enter the E3 formula:

View ($ D $ 3: $ D $ 22; divisions! $ A $ 3: $ A $ 7; Divisions!

The formula for the remaining cells (s E3 in E22) introduced into the E3 cell is E3.

Thus, a cycle will be performed that controls the parameter of which is the code division code "The magazine calculation of income from individuals" (Fig. 10).

Fig. 10. Filling the graph of the magazine calculation of the tax on income from individuals "Name of the division"

7. Configure the check in the "View of Work" field on the entered values \u200b\u200bwith the error message output. To do this, in MSExcel, select "Data Check". In the Count "Type of Data", choose the "list", "source" - "view of the place of work" (basic / not basic) (Fig. 11).

Fig. 11. Setting up the check in the "Workshop" field on the entered data with the error message output

Split-entered in the cell G3 formula for the remaining cells (with G3 in G22) of this graph. Now, when entering foreign values \u200b\u200bto the cell data, the program will issue an error message (Fig. 12).

Fig. 12 Error message when entering an extraneous value in the cell

We enter the J3 formula:

If (g3 \u003d "not basic"; F3; (F3- (bets! $ B $ 3) - (P * (rates! $ C $ 3)) -

(If (i3 \u003d "disabled"; rates! $ D $ 3)))) * (bets! $ A $ 3)%

The formula entered into the cell introduced into the cell for the remaining cells (with j3 in j22) of this graph.

Thus, a cycle will be performed, the control parameter of which is the graph of the failure of the table of the table "The magazine for calculating income from individuals" and the columns of the "Betting and Tax rates" table on the MSExcel bet worksheet (Fig. 13).

Fig. 13 Filling the chart of the magazine for calculating tax on income from individuals "NDFL"

9. In order to determine the total amount of personal income tax on each unit and the total listed organization, the amount of NDFL in a month must be created a summary table based on the data of the table "The magazine for calculating the income tax from individuals" (Fig. 14).

Fig. 14 Creating a summary table on the workstate "NDFL" MSEXCEL

10. Sheet 4 Rename into a list with the name "Results", on which a consolidated table is built (Fig. 15).

Fig. 15. Summary table on the work sheet "Results" MSEXCEL

11. In order for the results of the calculation results graphically, we construct a histogram according to the summary table (Fig. 16).

Fig. 16. Creation of a histogram according to the summary table on the work list the results of MSExcel

Graphic results of calculations are presented in Fig. 17.

Fig. 17 Works Leaf Results MSExcel

Conclusion

So, in the theoretical part of the course work, devices for long-term storage of data on PC were considered.

To work with the external memory, it is necessary to have a drive (device that provides the record and (or) reading information) and storage devices.

Main types of drives:

* storage devices on flexible magnetic disks (NGMD);

* storage drives on hard magnetic disks (NGMD);

* CD-ROM drives, CD-RW, DVD;

They correspond to the main types of media:

* Flexible magnetic discs (floppydisk) (3.5 "diameter" and a capacity of 1.44 MB; with a diameter of 5.25 "" and a capacity of 1.2 MB (currently outdated and practically not used, the release of drives intended for disks with a diameter 5.25 "", also stopped)), discs for interchangeable carriers;

* Hard Magnetic Disks (harddisk);

* CD-ROM discs, CD-R, CD-RW, DVD;

* Flash memory.

To date, optimal devices for long-term data storage, depending on the timing, volume and storage objectives, are: DVDs, hard drives, flash memory.

List of used literature

1. Groshev A.S. Informatics: Textbook for universities. - Arkhangelsk, Arkhang. State tehn University, 2010.

2. Informatics: laboratory workshop for students of 2 courses of all specialties. - M.: The university tutorial, 2006.

3. Kopras on computer science.

4. Odintsov B.E., Romanov A.N. Informatics in the economy: studies. benefit. - M.: School Textbook, 2008.

5. Yashin V.M. Informatics: PC hardware: studies. benefit. - M.: Infra-M, 2008.

Used for long-term storage of information and transmission. Long archival storage of data, or how to see the selfie of my great-grandmother? Use optical discs

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