Examples of external storage media. Abstract: Storage media

Media and drives The information that will be discussed in this book for recovery exists in binary form on various devices storage, or media. From the point of view of an ordinary user, a medium is a device capable of storing information and displaying it

12.2. Writing information to files and reading information from files Problem statement You want to save information on disk (for example, text, data, images, etc.)

External damage External damage is something that you need to pay attention to even before you pay money. First of all, inspect the laptop case for cracks. By and large, you should be told about such defects right away. Moreover, if they

Educational:

· Contribute to the formation of a system of knowledge, skills and abilities in the field of information and communication technologies used in education.

· Introduce modern digital media.

· Consider ways of interaction between a teacher and subjects of the pedagogical process and representatives of the professional community in a network information environment.

Educational:

·Develop and stimulate research activities students.

· Develop the ability to evaluate the benefits, limitations and selection of hardware to solve professional and educational problems.

· Contribute to the improvement of professional knowledge and skills by using the capabilities of the information environment.

Educational:

· Form motivation for information pedagogical activities.

IV. Hard disks.

V. SDRAM chips.

I. Modern digital media.

As a rule, multimedia fragments occupy a large amount of computer memory. And while storing large amounts of information on a computer, in particular on a Web server, does not cause any particular problems, transferring large amounts of information can take a very long time. For example, transferring information with a volume of 20 megabytes through a modem operating at a speed of 56 kilobits per second over Internet networks, will take almost an hour. Of course, information can be compressed and thereby reduce transmission time. However, they are best suited for storing and transporting multimedia curricula laser discs, which are widely used today and are known as CD-ROMs.

The most common memory devices at present:

§ Flash memory: USB drives, memory cards in phones and cameras, SSD

§ Optical discs: CD, DVD, Blu-Ray, etc.

§ Hard drives (HDD)

§ SDRAM chips (DDR and XDR)

The main parameters of the memory include information capacity (bits), power consumption, information storage time, and performance.

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

Specific external conditions can catastrophically reduce the storage life of data. For example, elevated temperatures or radiation (gamma ray and high-energy particle) exposure.

The erase speed varies from units to hundreds of milliseconds depending on the size of the erased block. The recording speed is tens to hundreds of microseconds.

Typically, the read speed for NOR chips is rated at tens of nanoseconds. For NAND chips, the read speed is tens of microseconds.

There are two main uses of flash memory: as a mobile storage medium and as software (“firmware”) storage. digital devices. Often these two applications are combined in one device.

Flash memory allows you to update the firmware of devices during operation.

Graduation writing assignment

Examination paper

Issued to student of group 35 Andrey Alekseevich Romanov

Profession: “Master of Digital Information Processing”

Topic: “Writing information to removable media”

I. Descriptive part

Introduction.

1. Basic terms and concepts

2. Review of storage media, their advantages and disadvantages, principles of operation, characteristics.

4. Selecting a program for recording information to media

Conclusion.

Bibliography.

Applications.

II. Practical task

1. Create instructions for recording information on the selected removable storage medium

2. Create a job test

3. Create a presentation about your work

The task was issued by the foreman O.S. Crack

The assignment was given to student A.A. Romanov

Ministry of Education and Science of the Udmurt Republic

Autonomous professional educational institution

Udmurt Republic

"College of Radio Electronics and information technologies»

Graduation written qualifying work

by profession "Master of processing" digital information»

student of group No. 35

Subject : “Writing information to removable media”

Izhevsk, 2015

Introduction

Storage medium(information carrier) - any material object or environment containing (carrying) information that can retain information entered into/on it in its structure for a sufficiently long time. Initially, the amount of information placed on the media was small (from 128 MB to 5.2 GB). Gradually, much more information began to be placed on the media (up to 3Tb).

The main storage media: floppy disks (floppy disks), hard disk drives (hard drives), CD, DVD (including Blu-ray), flash-memory (flash drives, memory cards).

CDs and DVDs have become a part of our lives. It’s hard to imagine where we would store gigabytes of music, movies and photographs if someone had not come up with these round records with a mirror surface.

On this moment this topic is relevant because modern man unable to live without information. But information has this peculiarity - it must be stored somewhere. There are quite a lot of information storage systems now. It can be stored on magnetic media, it can be stored on optical and magneto-optical media. But in our time, a person also faces quite important problem- transfer of information from one place to another, as well as the equally important problem of storing information, and as a consequence, the reliability of the media. This is why technologies related to information storage have developed so quickly.

The purpose of this graduation qualification written work is:

1. Create instructions for recording information onto the selected removable storage medium.

Based on this goal, the following tasks are set:

1. Review removable media, identify their advantages and disadvantages

2. Select a program for recording to removable media

Basic terms and definitions

Information- information perceived by a person or special devices as a reflection of the facts of the material world in the process of communication.

Recording information is a way of recording information on a tangible medium.

Removable storage media- a storage medium intended for its autonomous storage and use independent of the place of recording.

Media overview

FMD (Floppy Disk Media) or Floppy Disk(eng. Floppy Disk Drive) - a portable storage medium used for repeated recording and storage of data, which is placed in a protective plastic case a flexible magnetic disk (a 3.5″ disk has a more rigid case than a 5.25″ disk, while an 8″ disk has a very flexible case) coated with a ferromagnetic layer. Floppy disks typically have a write-protect feature that allows read-only access to the data. Floppy disks were widely used from the 1970s until the end of the 1990s, giving way to more capacious and convenient CDs and flash drives at the beginning of the 21st century.

Advantages:

1. Huge recording density with small media sizes.

2. Low power consumption compared to similar high-capacity media.

3. High reliability and stability.

Flaws:

1. Small recording capacity (in fact, even one song cannot be recorded on a disc).

2. Unreliability of information storage; the floppy disk is demagnetized under the influence of large magnetic fields.

HDD (Hard Magnetic Disk Media) or Winchester or Hard Disk(English HDD - Hard Disc Drive) is an information storage device based on the principle of magnetic recording. It is the main data storage device in most computers. It is combined with a storage device, a drive and an electronics unit and (in personal computers in the vast majority of cases) is usually installed inside the computer system unit, but there are also those connected externally.

Information is recorded on hard (aluminum or glass) plates coated with a layer of ferromagnetic material, most often chromium dioxide. HDD uses one or more plates on one axis. In operating mode, the reading heads do not touch the surface of the plates due to the layer of incoming air flow that forms near the surface during rapid rotation. The distance between the head and the disk is several nanometers (about 10 nm in modern disks), and the absence of mechanical contact ensures a long service life of the device. When the disks do not rotate, the heads are located at the spindle or outside the disk in a safe area, where their abnormal contact with the surface of the disks is excluded.

The principle of operation of hard drives is similar to the operation of tape recorders. The working surface of the disk moves relative to the read head (for example, in the form of an inductor with a gap in the magnetic circuit). When an alternating electric current is supplied (during recording) to the head coil, the resulting alternating magnetic field from the head gap affects the ferromagnet of the disk surface and changes the direction of the domain magnetization vector depending on the signal strength. When reading, the movement of domains at the head gap leads to a change in the magnetic flux in the head magnetic circuit, which leads to the appearance of an alternating electrical signal in the coil due to the effect of electromagnetic induction.

Recently, the magnetoresistive effect has been used for reading and magnetoresistive heads are used in disks. In them, a change in the magnetic field leads to a change in resistance, depending on the change in the magnetic field strength. Such heads make it possible to increase the likelihood of reliable information reading (especially at high information recording densities).

Advantages:

1. Allow you to write and read information many times.

2. When you turn off the computer, the information left on the hard drive is saved.

3. Large amount of stored information.

4. High reliability of data storage. The mean time between failures is about 300,000 hours, i.e. about 30 years.

Flaws:

1. It is impossible to carry it, since it is permanently attached to the system unit.

2. Relatively low performance, especially compared to RAM.

Recording methods

There are currently several recording methods:

· Longitudinal recording method.

· Perpendicular recording method.

· Thermal magnetic recording method.

Compact disc or CD(eng. Compact Disc) - optical media information in the form of a plastic disk with a hole in the center, the process of recording and reading information is carried out using a laser. Further development CDs became DVDs (more on them later).

The CD was originally created to store audio recordings in digital form, however, later it became widely used as a medium for storing any data in binary form.

CD-ROM(English: Compact Disc Read-Only Memory, read: “sidi-rom”) - a type of CD with data recorded on them that is read-only (read-only memory - read-only memory). CD-ROM is a modified version of CD-DA (disk for storing audio recordings), allowing you to store other digital data on it (physically it is no different from the first one, only the format of the recorded data has been changed). Later, versions were developed with the ability to both write once (CD-R) and rewrite multiple times (CD-RW) information on a disk. A further development of CD-ROM drives was DVD-ROM drives.

CD-ROMs- popular and most cheap remedy for software distribution, computer games, multimedia and other data. CD-ROM (and later DVD-ROM) became the main medium for transferring information between computers, displacing the floppy disk from this role (it is now giving way to more promising solid-state media).

The CD-ROM recording format also provides for recording mixed content information on one disc - simultaneously both computer data (files, software, readable only on a computer), and audio recordings (played on a regular audio CD player), video, texts and pictures. Such discs, depending on the order of the data, are called Enhanced CDs or Mixed-Mode CDs.

CD-R(Compact Disc-Recordable) is a type of compact disc (CD) developed by Philips and Sony for recording information once. CD-R supports all the features of the Red Book standard and, in addition, allows you to record data.

A regular CD-R is a thin disk made of transparent plastic (polycarbonate) 1.2 mm thick, 120 mm in diameter (standard), weight 16-18 g. or 80mm (mini). The capacity of a standard CD-R is 74 minutes of audio or 650MB of data. However, at the moment the standard CD-R capacity you can read 702MB of data or 79 minutes 59 seconds and 74 frames.

The polycarbonate disk has a spiral track to guide the laser beam when writing and reading information. On the spiral track side, the disc is covered with a recording layer consisting of a very thin layer of organic dye, then a reflective layer of silver, its alloy or gold. This layer is already covered with a protective photopolymerizable varnish and cured with ultraviolet radiation. And already on this protective layer various inscriptions are applied with paint.

A CD-R always has a service track with servo marks ATIP - Absolute Time In Pregroove - absolute time in the service track. This service track is needed for the tracking system, which keeps the laser beam while recording on the track and monitors the recording speed. In addition to synchronization functions, the service track also contains information about the manufacturer of this disc, information about the material of the recording layer, the length of the track to be recorded, etc. The service track is not destroyed when data is written to the disk, and many copy protection systems use it to to distinguish the original from the copy.

CD-RW(English Compact Disc-ReWritable, Rewritable CD) - a type of compact disc (CD), developed in 1997 for repeated recording of information

CD-RW is a logical development of CD-R, however, unlike it, it allows data to be rewritten many times. This format was introduced in 1997 and during its development was called CD-Erasable (CD-E, Compact Disc Erasable). CD-RW is similar in many ways to CD-R, but its recording layer is made of a special chalcogenide alloy, which, when heated above its melting point, transforms from a crystalline state of aggregation to an amorphous one.

DVD(eng. Digital Versatile (Video) Disc - digital multi-purpose (video) disk) - an information carrier made in the form of a disk, the size of a CD, but with a denser working surface structure, which allows you to store and read a larger amount of information in due to the use of a laser with a shorter wavelength and a lens with a larger numerical aperture.

The first discs and DVD players appeared in November 1996 in Japan and March 1997 in the USA.

In the early 1990s, two standards were being developed for high-density optical media. One of them was called Multimedia Compact Disc (MMCD) and was developed by Philips and Sony, the second - Super Disc - supported 8 large corporations, which included Toshiba and Time Warner. Later, the efforts of the standards setters were united under the leadership of IBM, which did not want a repeat of the format war, as was the case with the VHS and Betamax cassette standards in the 1970s. The DVD was officially announced in September 1995, when the first version of the DVD specifications was published. Changes and additions to the specifications are made by the DVD Forum (formerly called the DVD Consortium), whose members are 10 founding companies and more than 220 individuals.

The DVD-R(W) recording standard was developed in 1997 by the Japanese company Pioneer and a group of companies that joined it and were included in the DVD Forum as the official specification for recordable (and subsequently rewritable) discs.

In magnetic tape drives (most often such devices are streamers), recording is done on mini-cassettes. The capacity of such cassettes is from 40 MB to 13 GB, the data transfer speed is from 2 to 9 MB per minute, the tape length is from 63.5 to 230 m, the number of tracks is from 20 to 144.

CD-ROM is a read-only optical storage medium that can store up to 650 MB of data. Accessing data on a CD-ROM is faster than data on floppy disks, but slower than on hard drives. CD-ROM is a one-way storage medium. More popular are CD-RW drives, which allow you to write and rewrite CD-RW discs, write CD-R discs, read CD-ROM discs, i.e. are in a certain sense universal.

The abbreviation DVD stands for Digital Versatile Disk, i.e. universal digital disk. Having the same dimensions as a regular CD and a very similar operating principle, it holds an extremely large amount of information - from 4.7 to 17 GB. Perhaps it is precisely because of its large capacity that it is called universal. True, today the DVD disc is actually used in only two areas: for storing video films (DVD-Video or simply DVD) and ultra-large databases (DVD-ROM, DVD-R).

26-27.input/output device- component standard architecture A computer that provides a computer with the ability to interact with the outside world and, in particular, with users and other computers.

Divided into:

---Input device:-Graphic input devices Scanner, Video and Web camera, Digital camera, Video capture card, Microphone, Digital voice recorder

Text input devices: Keyboard

Pointing devices: Mouse, Trackball, Trackpoint, Touchpad, Joystick, Roller Mouse, Graphics tablet, Light pen, Analog joystick, Touchscreen

Gaming input devices: Joystick, Pedal, Gamepad, Steering wheel, Flight simulator lever (wheel, Airplane control stick), Dance platform

---Output device-Devices for displaying visual information: Monitor (display), Projector, Printer, Plotter, Optical drive with disc marking function, LEDs (on a system unit or laptop, for example, informing about disc reading/writing)

Audio output devices: Built-in speaker, Speakers, Headphones

---I/O devices: Magnetic drum , Streamer , Drive , HDD , Various ports , Various network interfaces.

Channels input-output channel (English IOC - input-output channel), hereinafter referred to as IOC, and interfaces provide interaction central devices machines and peripherals.

KVVs are logically independent devices that operate under the control of their own programs located in memory.

KVV and interfaces perform the following functions

Allows you to have machines with a variable composition of peripheral devices.

Ensure parallel operation of peripheral devices both among themselves and in relation to the processor.

Provide automatic recognition and response of the processor to various situations, arising in peripheral devices.

Multiplex channel

The channel itself is fast, but serves a slow peripheral device. At the same time, having connected to one device, it sends one machine word, and after that connects to another.

Selector channel

The channel is fast and serves fast devices. At the same time, having connected to one device, it transmits all the information, and after that it connects to another device.

28. Keyboard, key assignments - computer device, which is located in front of the display screen and is used for typing text and controlling the computer using the keys on the keyboard.

All keys can be divided into several groups:

alphanumeric keys; function keys; control keys; cursor keys;

number keys. In the center are alphanumeric keys, very similar to the keys of a regular typewriter. They contain numbers, special characters (“!”, “:”, “*”, etc.), letters of the Russian alphabet, Latin letters. Using these keys you will type all kinds of texts, arithmetic expressions, and write down your programs. At the bottom of the keyboard is big key without symbols on it - “Space”. "Space" is used to separate words and expressions from each other. Russian keyboards are bilingual, so their keys have characters from both the Russian and English alphabets. In the Russian language mode, texts are typed in Russian, English - in English. The alphanumeric keyboard is the main part of the keyboard with the alphanumeric keys on which the characters are drawn, along with all the closely adjacent control keys. The function keys F1 – F12, located at the top of the keyboard, are programmed to perform certain actions (functions). So, very often the F1 key is used to call up help.

To move the cursor, use the cursor keys; they have arrows pointing up, down, left, and right. These keys move the cursor one position in the corresponding direction. The PageUp and PageDown keys allow you to “scroll” the document up and down, and the Home and End keys move the cursor to the beginning and end of the line.

The Esc key is located in top corner keyboards. Usually serves to abandon an action just performed.

Shift keys, Ctrl, alt correct the actions of other keys.

Numeric keys - when the indicator is on Num Lock convenient keypad with numbers and symbols arithmetic operations. Arranged like a calculator. If the Num Lock indicator is off, then cursor control mode works

29, Memory devices, computer classification, principle of operation, basic characteristics. storage device - a storage medium intended for recording and storing data. The operation of a storage device can be based on any physical effect that brings the system to two or more stable states.

Classification storage devices

Based on the stability of recording and the possibility of rewriting, memories are divided into: - Permanent storage (ROM), the contents of which cannot be changed by the end user (for example, BIOS). ROM in operating mode allows only reading information. ---Writable memory (PROM), in which end user can write information only once (for example, CD-R). ---Multiple rewritable memory (PROM) (for example, CD-RW).--Running memory (RAM) provides a mode for recording, storing and reading information during its processing . Fast but expensive RAM (SRAM) is built on flip-flops, while slower but cheaper types of RAM - dynamic memory (DRAM) are built on capacitors. In both types of memory, information disappears after disconnection from the power source (for example, current).

By type of access, storage devices are divided into: - Sequential access devices (for example, magnetic tapes). - Random access (RAM) devices (for example, random access memory). - Direct access devices (for example, hard magnetic disks). .---Devices with associative access (special devices to increase database performance) By geometric design:--disk (magnetic disks, optical, magneto-optical);---tape (magnetic tapes, punched paper tape);--drum (magnetic drums );--card (magnetic cards, punched cards, flash cards, etc.)---printed circuit boards (DRAM cards, cartridges).

According to the physical principle: - perforated (with holes or cutouts) – punched card ===punched tape==with magnetic recording ==ferrite cores==magnetic disks ==Hard magnetic disk==Floppy magnetic disk==magnetic tapes==magnetic cards =optical ==CD==DVD==HD-DVD==Blu-ray Disc

Main characteristics of the memory

The most important characteristics Memory is information capacity and speed.

The information capacity of a memory is determined by the number of units of information that can be stored in it. As a rule, information capacity refers only to the useful volume of stored information; it does not include the size of memory occupied by service information, for example, reserve areas, sync tracks, engineering cylinders, etc. The performance of the memory is characterized by its timing characteristics, which include:

The access time (cycle time) characterizes the maximum frequency of access to a given memory when reading or writing information. The time for reading (sampling) information is the time interval for accessing the memory from the submission of the read signal to the receipt of the output signal. Information recording time is the time interval from the moment the signal is sent to access the memory until the moment the memory is ready to receive the next piece of information. Important characteristics of the charger are also reliability, device weight, dimensions, power consumption and cost.

30, Microprocessors,their characteristics, controllers. Microprocessor - processor (device responsible for performing arithmetic, logical operations and control operations written in machine code), implemented as a single chip or a set of several specialized chips (as opposed to implementing a processor in the form electrical diagram on an elemental basis general purpose or in the form program model). The first microprocessors appeared in the 1970s and were used in electronic calculators. Soon they began to be built into other devices, such as terminals, printers and various automation systems. Affordable 8-bit microprocessors with 16-bit addressing enabled the creation of the first consumer microcomputers in the mid-1970s. Microprocessors are characterized by: 1) clock frequency, which determines the maximum execution time for switching elements in a computer;

2) bit depth, i.e. the maximum number of simultaneously processed binary bits. 3) architecture. The concept of microprocessor architecture includes a system of commands and addressing methods, the ability to combine the execution of commands in time, the presence of additional devices in the microprocessor, principles and modes of its operation .Microcontroller(eng. Micro Controller Unit, MCU) - a microcircuit designed to control electronic devices. A typical microcontroller combines the functions of a processor and peripheral devices and contains RAM or ROM. Essentially, it is a single-chip computer capable of performing simple tasks. The most important characteristics of a microprocessor are:

31. Microcomputers and their classes. Computers of this class are available to many enterprises. Organizations using microcomputers usually do not create computer centers. To maintain such a computer, they only need a small computing laboratory consisting of several people. The staff of a computing laboratory necessarily includes programmers, although they are not directly involved in program development. The necessary system programs are usually purchased together with the microcomputer, and the development of the necessary application programs ordered by larger computing centers or specialized organizations. The following classification of microcomputers can be given: -- Universal -- Multi-user microcomputers are powerful microcomputers equipped with several video terminals and operating in time-sharing mode, which allows several users to work effectively on them at once. -- Personal computers (PCs) are single-user microcomputers that meet the requirements of general accessibility and versatility of use, designed for one user and controlled by one person - Laptop computers are usually needed by business leaders, managers, scientists, journalists who have to work outside the office - at home, at presentations or in business trip time.

Main varieties laptop computers:

Laptop. It is close in size to a regular briefcase. In terms of basic characteristics (speed, memory) it is approximately the same as a desktop PC. Now computers of this type are giving way to even smaller ones.

Notebook. It is closer in size to a large format book. It weighs about 3 kg. Fits in a briefcase. To communicate with the office, it is usually equipped with a modem. Laptops often come with CD-ROM drives. Many modern laptops include interchangeable blocks with standard connectors. You can insert a CD drive, a magnetic disk drive, a spare battery, or a removable hard drive into the same slot as needed. The laptop is resistant to power failures. Even if it receives energy from a regular power supply, in case of any failure it instantly switches to battery power.

Palmtop (handheld) - the smallest modern personal computers. Fits in the palm of your hand. Magnetic disks are replaced by non-volatile electronic memory. There are no disk drives either - the exchange of information with ordinary computers goes through communication lines.

Despite the relatively low performance compared to large computers, microcomputers are also used in large computer centers. There they are entrusted with auxiliary operations for which there is no point in using expensive supercomputers. Such tasks, for example, include preliminary preparation data.

Servers are multi-user powerful microcomputers in computer networks, dedicated to processing requests from all network stations. Servers are usually classified as microcomputers. Server is a computer dedicated to processing requests from all stations of a computer network, providing these stations with access to common system resources(computing power, databases, program libraries, printers, faxes, etc.) and distributing these resources.

Information carriers – material that is intended for recording, storage and subsequent reproduction of information.

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

Storage medium - This physical environment, in which it is fixed.

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

IN modern society There are three main types of storage media:

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

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

3) optical.

Information carriers include:

Magnetic disks;

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

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

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

- optical discs- an information carrier in the form of a disk with a hole in the center, information from which is read using a laser. The compact disc was originally created for digital audio storage, but is now widely used as a general-purpose storage device;

- flash memory- a type of solid-state semiconductor non-volatile rewritable memory. Flash memory can be read as many times as you like, but it can only be written to a limited number of times (usually about 10 thousand times). Erasing occurs in sections, so you cannot change one bit or byte without overwriting the entire section.

All media can be divided into:

1. Human readable (documents).

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

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

However fast development funds computer technology erased the line between the 1st and 3rd groups - a scanner appeared that allows you to enter information from documents into the computer’s memory.

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

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

1. by type of record:

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

– magnetic-optical systems, also called MO;

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

2. by construction methods:

– a rotating plate or disk (like a hard drive, floppy disk, removable disk, CD, DVD or MO);

– tape media of various formats;

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

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

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

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

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

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

For long-term storage For information on a computer, removable media are widely used, such as optical disks, flash memory, and an external hard drive.

Optical discs

Data can be stored on optical discs in CD format (from the English Compact Disc), with a capacity of up to 700 MB and DVD format discs (from the English Digital Versatile Disc - digital multi-purpose disk), with a capacity of up to 4.7 GB for single-layer discs (SL - Single Layer) and 7.9 GB for double-layer (DL – Double Layer).

In turn, optical discs are divided into disposable discs, which can be written only once - CD-R (or DVD-R) discs, and reusable discs, which can be rewritten multiple times - CD-RW (or DVD-RW) discs.

In computer jargon, blank discs without recording are called “blanks,” and the recording process is called “burning.” To read and write discs, a special device called CD drive - DVD-ROM, which is installed in, the receiving tray of the device goes to the front panel of the system unit. DVD-ROM is universal device, allowing you to both read and write discs of both formats (CD and DVD). In order to place a disc in the drive, you need to press a button on its panel; a tray will slide out of the drive, onto which you need to place the disc, shiny side down. Then press the button again or lightly push the tray itself so that it closes.

Flash memory

Flash memory (USB Flash drive). Now even the most distant person from computers has probably heard the word. This is flash memory. Today, flash drives are rapidly replacing optical disks due to ease of handling, memory capacity, writing and reading speed.

At the time of writing, flash drives with capacities from 4 GB to 128 GB are available for sale. How more capacity, the more expensive the flash drive. In addition, flash drives have different speed recording and reading, but in any case it is several times higher than that of optical disks.

To connect a flash drive to a computer, you just need to insert it into the USB connector (port) on the front or rear panel of the system unit.

Memory cards, familiar to us as storage media in smartphones and digital cameras, also belong to flash memory and can serve removable media in computer. In this case, reading and writing data is performed by a card reader, which can be built into system unit or connected to it via USB port. The capacity of memory cards varies from 4 GB to 128 GB.