Main characteristics of long-term memory devices. Long-term memory

Long-term (external) memory is a non-volatile memory designed for long-term storage of information.

The processor does not have direct access to the contents of the external memory. In order for the processor to process data from non-volatile memory, it must first be loaded into RAM. Currently, the main non-volatile memory devices include magnetic hard disks, optical disk drives, and flash memory devices. Previously, magnetic tapes, floppy disks, magneto-optical disks were also used for long-term storage of information.

The main external memory device is hard magnetic disk(picture 1). Inside hard disk there are one or more plates mounted on a common spindle. Data is usually recorded on both sides of each platter, although in some hard drives manufacturers can use single-sided platters along with double-sided platters. Writing and reading information is carried out using the read / write heads. A motor is located under the plates, which rotates them at a fairly high speed. The rotational speed of the plates is measured in revolutions per minute (rpm). The first hard drives had a rotational speed of 3600 rpm. In modern hard drives, the rotational speed has increased to 7200, 10,000 and 15,000 rpm.

Figure 1 - Hard disk

During the recording process, the digital information stored in the RAM is converted into an alternating electric current, which is fed to the magnetic head, and then transferred to the magnetic disk, but in the form of a magnetic field. After termination external field zones of remanent magnetization are formed on the surface of the disk. Front using hard the disk needs to be formatted.

Formatting includes three stages.

1. Low-level formatting disk. In this process, physical structures are created on the hard disk: tracks, sectors, control information. This process is carried out by the manufacturer on plates that do not contain any information yet.

2. Partitioning. This process splits the hard drive into logical drives(C :, D :, etc.). This function is performed by the operating system.

3. High-level formatting. This process is also performed by the operating system and depends on its type. High-level formatting creates logical structures responsible for the correct storage of files, as well as, in some cases, system boot files at the beginning of the disc.

Hard drives were originally designed as internal devices and were not designed to be Reserve copy and transferring information from one computer to another. About 20 years ago, the most common device for this purpose was floppy disks (floppy disks). However, their capacity by modern standards was very small (1.44 MB), so they were replaced by optical discs CDs (compact disks), allowing to store large amounts of information (650-800 MB) and much superior to floppy disks in terms of reliability. To work with CDs on your computer, you need a special drive (optical drive).

An overview of the hard drive is presented in video 1:

Hard drive overview MTS

Video 1 - Hard drive overview

A distinction is made between read-only discs (CD-ROMs), industrially produced, write-once (CD-R) and write-rewriteable (CD-RW). Discs of the last two types are intended for recording on special recording optical drives. All types of disks have the same storage structure. The data is written using a red laser beam on a spiral track running from the center of the disc to its periphery. There are depressions called pitas along the path. On recordable discs, pits are imitated by dark spots of a special recording layer, resulting from heating the desired area with a laser. Any information is encoded by alternating grooves and spaces between them.

DVDs have a higher data density than CDs. There are discs on which information is recorded in two layers. DVD discs can be 4.7 GB or 8.5 GB depending on the settings above. All CDs (both CDs and DVDs) have the same storage structure. The read / write speed of optical drives is measured in multiples of the base speed (denoted 16x, 24x, 48x, etc.). For CD drives, the base speed is 150 Kb / s, for DVD drives, 1.385 Mb / s.

Blu-ray (Blu-ray Disc) is the name of the format optical disc next generation. Blu-Ray uses a blue laser to write and read data instead of the red laser used in DVDs and CD-ROMs. The blue laser has a wavelength much shorter than the red laser. This allows the thickness of the data track to be thinned, resulting in a significant increase in the storage capacity of the media. The format was designed to allow video recording, rewriting and playback high resolution(HD-video), as well as for storing large amounts of data. The capacity of the new format is from 25 to 50 GB.

By device flash memory(flash memory) resembles a dynamic volatile memory microcircuit, in which transistors are installed in memory cells instead of capacitors. When voltage is applied, the transistor takes one of the fixed positions - closed or open. It remains in this position until a new one is fed to it. electric charge that changes its state. Thus, a sequence of logical zeros and ones is formed in this type of memory like static memory: closed for passing electric current cells are recognized as logical ones, open cells - as logical zeros.

USB flash drive (flash drive, Figure 2) is a device based on flash memory for storing and transferring data from one computer to another.

Figure 2 - Flash drive

The flash memory is enclosed in a housing that resembles appearance trinket. The interface for connecting to a computer is USB. The capacity of modern flash drives reaches 128-256GB and continues to grow at a rapid pace.

Computer memory is a special device for recording and storing various kinds of data. There are two types of memory in a computer device: operational and permanent (internal and external).

RAM- a fast type of memory that allows you to write and read data at high speed, but at the same time information is stored in it only when it is turned on computer device, that is, when electricity is supplied to it. It is this nuance that makes RAM unsuitable for long-term storage of information. Turn off the computer - and all information from the RAM will be erased. The purpose of RAM is to write-read information at a high speed. installed programs and the operating system. Booting the computer at startup is just loading the programs necessary for the operation into RAM. There are several types of RAM: SDRAM, DDR, DDR2, DDR3. Each subsequent type of memory is an improvement of the previous one and allows new memory work at a higher speed. At the moment in modern computers RAM type DDR3 is used. The choice of RAM depends on the connectors on the motherboard. Permanent memory is a type of memory that allows you to store information even when the computer is turned off. The most common variant of persistent storage is HDD hard disks. They represent one or more magnetic disks rotating at a tremendous speed (from 5 to 12 thousand revolutions per minute), and heads designed for reading and writing information. HDDs are reliable storage media, they allow you to write and read information a huge number of times. Their only drawback is that they are very susceptible to shocks, falls and other mechanical influences, especially at the time of work. Are gaining more and more distribution solid state drives SSD. This view persistent storage evolved from USB flash drives. The main advantages and disadvantages of SSD drives:

have several times higher read and write speed than HDD;
not susceptible to mechanical stress;
the cost of SSD drives is several times higher than the fee for an HDD;
have a finite number of read-write cycles.

CDs and DVDs are also referred to as read-only memory in a computer, and are relatively inexpensive options for storing small amounts of information. The danger of losing information on these media consists in their mechanical damage: scratches, fractures, thermal effects.

Each type of computer memory has its own advantages and disadvantages, but there are some without which the computer will not work. CDs and DVDs, USB flash drive, removable hard drive are optional accessories in system unit, and without RAM and a local hard drive, the device will not function.

The main function of external (long-term) memory is the ability to store a large amount of information for a long time. To work with external memory, you must have storage(disk drive) and storage devices - carrier.

The media include floppy (Floppy Disk) and hard (Hard Disk) magnetic disks, as well as optical disks CD-ROM, CD-RW, DVD, removable disks... Their indicators such as information capacity, time of access to information, reliability of its storage, and uptime are essential.

Hard magnetic disk (HDD - Hard Disk Drive) is a device for permanent storage of information used when working with a PC: programs operating system, frequently used application programs, documents. A magnetic hard disk is a chamber inside which there are several disks on the same axis. The features of hard drives are:

The highest speed of reading and writing information;

Information capacity for modern HDDs up to 100 GB and more.

Protect hard drives from shocks and sudden changes in spatial orientation during operation.

Removable hard disk drives. ... Zip - available as built-in or stand-alone units connected to a parallel port, they can store 100 and 250 MB of data on cartridges resembling a floppy disk. Jaz - the capacity of the used cartridge is 1 or 2 GB. The disadvantage is the high cost of the cartridge. The main application is data backup.

Streamers - These are magnetic tape drives that are currently used mainly as a means of backing up data. Recording is made on mini-cassettes. The capacity of such cassettes is from 40 MB to 13 GB.

Disk drives - devices for working with information carriers (read / write).

I. FDD- Floppy Disk Drive floppy disk drive . The geometric size of the floppy disk is 3.5 inches (89 mm), the information capacity is 1.44 MB. Peculiarities:

Low speed of reading / writing data;

Small information capacity of a floppy disk;

Low reliability of storing data on floppy disks.

Do not store floppy disks near magnetic sources (monitor, mobile phone etc.), keep out dust, dirt and liquids.

II. Laser drives CD-ROM, DVD-ROM - devices for working with laser discs:

- CD-ROM(Compact Disk Read Only Memory- CD-ROM read-only). The information capacity is 650-800 MB. The main disadvantage of standard floppy drives CD-ROM is the impossibility of recording data.

- DVD-ROM (Digital Versatile Disk- universal digital disk) ... DVD capacities range from 4.7GB to 17GB. The variation in capacity is due to the fact that the disc can be recorded from two sides and, moreover, one or two layers of information can be applied on each side. Thus, single-sided single-layer discs have a volume of 4.7 GB, double-sided single-layer discs - 9.4 GB, single-sided double-layer discs - 8.5 GB, double-sided double-layer discs - 17 GB.

III. Recordable laser drives to work with both the listed types of CDs and media such as:

- CD-R, DVD-R (R - recordable - recordable ) – write-once laser discs.

- CD-RW, DVD-RW (RW - R e W ritable) - rewritable laser discs.

Optical disks have high reliability of information storage, durability (service life with high-quality performance is 30-50 years). Discs should be stored vertically in hard cases, protected from sunlight and liquids, protected from magnetic radiation, scratches, cracks, dust.

Flash memory - are a microcircuit placed in a case. The flash memory card is inserted into mobile device(laptop, digital camera) and connects to PC via USB port through dedicated USB cable or directly plugs into the USB port. The information capacity of the card, depending on the type, reaches 1 GB or more.

Flash memory cards should not be stored near magnetic sources, dirt, dust, and liquids should be kept away.

Lesson "Working and long-term memory" in grade 8. The lesson is designed for 1 hour. According to the program of N.D. Ugrinovich (34 hours). Appendix: test on the topic at the end of the lesson for the assimilation of the material plus a presentation.
According to the new federal state educational standards, this topic is seventh grade.

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Slide captions:

RAM and long-term memory of the computer

Operating memory Cell number Information in cell 1 073 741 823 11111111 …… .. …… .. 4 00000000 3 11110000 2 00001111 1 10101010 0 01010101 RAM is a sequence of numbered cells starting from zero. Each cell can store binary code, eight characters long.

Random access memory The amount of computer RAM can be determined by the formula: I op = I cell * N where: I cell - the amount of information stored in the cell N - the number of cells Example: In the computer, the number of memory cells is 1 073 741 824 The amount of information in each cell , I cell = 8 bits = 1 byte Then the information volume of the random access memory this computer is equal to: I op = I cell * N = 1 byte * 1 073 741 824 = 1 073 741 824 bytes / 1024 = 1 048 576 KB / 1024 = 1024 MB = 1 GB

Random access memory Random access memory is manufactured in the form of memory modules are installed in special slots on motherboard computer memory modules

Long-term memory HDD optical disk Memory card (flash memory) Flash disk floppy disk

Non-volatile memory Hard magnetic disk

Non-volatile memory Optical disc The surface of an optical disc has areas of varying reflectivity. The drive's laser beam hits the surface of the disk, is reflected and converted into a digital computer code (reflects - 1, does not reflect - 0).

Long-term memory Non-volatile memory Flash -disk from the inside: 1. USB-connector. 2. Microcontroller. 3. Control points... 4. Chip Flash-memory. 5. Quartz resonator. 6. LED. 7. Switch "write protection". 8. Space for an additional memory chip.

Non-volatile memory Non-volatile memory The flash memory card is a large integrated circuit (LSI) housed in a miniature flat case. To read information from memory cards, special adapters are used.

Homework Textbook, §§ 2.2.4, 2.2.5, control questions orally, assignments 2.1, 2.2 in writing in a notebook.

http://great.az/index.php?newsid=8153 http://lib.rus.ec/b/331980/read http://www.ru.all.biz/g672155/ Resources:

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Lesson on the topic: “Operative and long-term memory. 8th grade"

Lesson type: familiarization with new material.

Lesson type: mixed.

At the time of the lesson, students should
know:

The main components of the computer, the composition of the system unit;

The main-modular principle of building a computer;

Input devices and information output devices;

Purpose and main characteristics of the processor;

Appointment and structure of the motherboard.

be able to :

Determine the characteristics of the main devices of the computer;

Briefly outline the main points of the lesson;

Be clear about your answer.

Lesson objectives:
- repeat the topic "Processor and motherboard";
- to give the concept of operational and long-term memory;

To teach how to use the knowledge gained in practice.

Lesson Objectives:

educational:to acquaint students with the types of computer memory; introduce the concepts of "random access memory", "long-term memory", "non-volatile memory", expand the understanding of computer devices.

educational: the formation of information culture.

developing: development of thinking, memory, attentiveness.

As a result of studying this topic, students should

know:

Purpose of the RAM and long-term memory of the computer;

Peculiarities different types computer memory;

The device of the operative and long-term memory of the computer.

be able to:

Calculate the informational amount of RAM;

Compare the information volume of different media.

During the classes:

1.Organizational moment:
- greeting, report of the attendant about absent.

2. Updating knowledge, checking homework:
- Frontal poll:

1. What is the purpose of the processor in the computer?

(answer: A processor is a device that performs all arithmetic and logical operations and controls other computer devices).

2. What characteristics of the processor affect its performance?

(Answer: Processor performance depends on clock frequency and bit depth).

3. What is the motherboard for?

(Answer: The motherboard is hardware device computer. All major computer systems are located on it.).

4. What is installed on the system board?

(answer: processor, random access memory (RAM) cards, read-only memory (ROM), buses - a set of conductors through which signals are exchanged between the internal devices of the computer)

5. What connectors are available on the system board?

(Answer: connectors for installing the processor and RAM modules, connectors for connecting additional devices(slots), connectors for connecting external devices).

Visual check of homework.

3. Learning new material.

Lesson motto: “Do not be afraid when you don’t know: it’s scary when you don’t want to know”

Guys, today in the lesson we will get acquainted with the types of computer memory(slide 1). The very concept of "memory" is associated with human memory. Indeed, the memory of a computer is similar to the memory of a person. A person is able to remember some events all his life, and he does not remember some information for a long time, only as long as there is a need for it.(you can ask students to give 2-3 examples of information that a person stores in his memory for a long time and information that is needed for a very short time).

The computer also has a long-term memory, where information is stored permanently until the user deletes it as unnecessary. And there is RAM, where information is stored as long as the computer is turned on. When the computer is turned off, all information from the RAM is deleted.

And yet, the difference between human memory and computer memory is colossal - the work of the computer is subordinated to the program embedded in it, and the person himself controls his actions.

So, let's figure out how the computer's RAM works.(slide 2).

RAMis a sequence of cells numbered starting from zero. Each memory cell can store a binary code with a length of eight characters.

(slide 3) Volume I op RAM of a computer can be determined if the amount of information I ball stored in each cell, multiply by N - the number of cells.

I op = I cell * N

The amount of information stored in each cell, I ball = 8 bits = 1 byte. Knowing the number of RAM cells, you can calculate the amount of computer RAM. For example, the number of cells is 1,073,741,824. Then:

I op = I cell * N = 1 byte * 1,073,741,824 = 1,073,741,824 bytes / 1024 = 1,048,576 KB / 1024 = 1024 MB = 1 GB

(slide 4) Random access memory is manufactured in the form of memory modules, which are plates with electrical contacts, on the sides of which large integrated circuits (LSI) are placed. Memory modules are installed in special connectors on the computer's motherboard.

For long-term storage of information is usedlong-term (external) memory.On such media, information is stored in the form of a binary code,those. in the form of sequences of zeros and ones.

Non-volatile memory devices include:(slide 5)

Hard magnetic disk (hard drive);

Optical discs (CD, DVD);

Flash memory, flash disks;

Until recently, floppy disks (floppy disks) were used, but due to their small information volume (1.44 MB), they are a thing of the past.

Let's take a closer look at these devices.

(slide 6)

Hard magnetic disk- several thin metal discs rotating very quickly on one axis are enclosed in a metal case. Information on disks is stored on concentric tracks, on which magnetized and non-magnetized areas alternate. The magnetized section stores the computer unit 1, and the non-magnetized one stores the computer zero 0. To write or read information, the magnetic head of the disk drive is installed on a certain concentric track of the disc and the information is written or read.

(slide 7)

Optical discs.Information on an optical disc is stored on a single spiral-like track running from the center of the disc to the periphery and containing alternating areas of poor and good reflectivity.

In the process of reading information from the optical disc, the laser beam installed in the drive falls on the surface of the rotating disc and is reflected. Since the surface of the optical disc has areas with different reflectivity, the reflected beam also changes its intensity and is converted into a digital computer code (reflects - 1, does not reflect - 0).

There are several types of optical discs:

CD and CD-RW discs. They can store up to 700 MB of information;

DVD and DVD-RW discs. The capacity of such disks is 4.7 GB.

CDs and DVDs are not rewritable. Information is recorded on them once. CD-RW and DVD-RW discs can be recorded multiple times (but a limited number of times).

(slide 8)

Non-volatile memory - cards flash memory and flash disks. They do not require a source connection electrical voltage and have no moving parts, so they provide high data security.

Flash memory card is a large integrated circuit (LSI) housed in a miniature flat case. To write and read information from memory cards, special adapters are used (built-in portable devices or connected to computers using - USB-connector).

(slide 9)

Flash disk is a memory LSI placed in a miniature case and is connected to the USB-connector of a computer.

4. Securing the material.

We got acquainted with the types of computer memory. Now let's consolidate the knowledge that you received in the lesson with the help of the test. We sit down at computers, open "Testing" Sign ", test" Working and long-term memory ".(Taking the test on a computer. Testing in the Znak program saves time and students receive grades immediately. In addition, after completing the test, they see all the correct answers and can check themselves).

Annex 1 .

5. Lesson summary.

Recording homework, assigning marks.

Grades are set based on the results of testing, taking into account the work of individual students in the lesson.

(slide 10) Homework: Textbook by N.D. Ugrinovich. Informatics and ICT. 8th grade. §§ 2.2.4, 2.2.5, control questions orally, tasks 2.1, 2.2 in writing in a notebook.

(slide 11) Thanks for the lesson!

Used literature: ND Ugrinovich. Informatics and ICT. 8th grade

Non-volatile memory - information storage with unlimited storage capacity and duration. Computers are also quite voluminous, long-term storage of information, but they have their strengths and weaknesses in this regard. The problem lies not in the quantity and shelf life, but in the method of obtaining access to information (see table).

There are situations when you are trying to remember something (name, title, etc.), the word literally “spins on the tongue,” but you cannot remember. Facts and names related to what needs to be remembered come to mind, but it is not possible to finally formulate the information. You can "fish out" only part, but not all of the information. Surprisingly, if you stop torturing yourself, a few seconds later it will pop up in your head on its own. Long-term memory is very complex and information is encoded in a complex communication system. Having restored some components of information, you reproduce some connections in the network and after a while you can get all the necessary data.

From a design point of view, two questions are of interest:

■ Under what conditions does information get into the fiberboard?

■ How much does it “cost” to remember?

Both questions are very interesting from the point of view of user training, the second question, moreover, is also interesting from the point of view of improving the ability of users to maintain their skills in working with the system for a long time (and this is one of the main characteristics of a good interface).

Inside the fiberboard. It is now believed (and this opinion is unlikely to be changed in the future) that information gets into the fiberboard in three cases. At first, on repetition, that is, when cramming. Secondly, with deep semantic processing... Thirdly, in the presence of a strong emotional shock... Emotional shock is of little interest to us - do not really stand behind the user's back, shooting from time to time with a gun, so that he gets worried (especially since after the shock, memorization is interrupted). Repetition with processing is enough.

Repetition is simple. The more repetitions and the less time elapses between repetitions, the more likely the information will be remembered. For us, as “simple people,” this is clear and uninteresting, but from the point of view of interface design, this observation causes a very simple heuristic: if the system has to be used often, users will learn it, they have nowhere to go. This is a very comforting observation.

Things are more interesting with semantic processing. The fact is that information is stored in fiberboard in a highly structured form (for example, it seems that visual memories are actually stored not in the form of a picture, but as a list of objects in the image, while the image individual objects stored separately). So, to access memories, the brain does the same job as looking for a book in a library (only more difficult; try using introspection to remember, for example, all your classmates). Accordingly, when a person remembers, he delves into his memory and finds more and more signs of the required information. But the opposite is also true: the more a person thinks about any information, the more he correlates it with other information already in his memory, the better he will remember what he is thinking (i.e., the current stimulus). This is also a very comforting observation: if a user is tormented for a long time trying to understand how the system works, he will remember it for a long time, if not forever.

Somewhat helps to understand the structure of the mechanism of remembering its antipode, namely forgetting. Modern science argues that forgetting is due to one of three factors (or all three), namely fading, interference and difference in situations. The simplest explanation is fading: when information is not used long time, it is forgotten. It's a little trickier with the two remaining factors.

It is assumed that if several fragments of similar information have undergone similar semantic processing, these fragments are mixed in memory, making it almost impossible to reproduce the damaged fragment, i.e., the fragments interfere with each other. The situation is different with the difference of situations. It is assumed that successful recollection requires the matching of features during encoding with features during reproduction. It is impossible to recall “that, I don’t know what” for a reason. It's like losing a book card in the library - the book is safe and sound, but there is no way to find it.

Seriously though, repetition can be characterized as a powerful but unreliable method, since it is difficult to count on repetition if you work with the system infrequently (there are many systems that are used rarely or even once). Semantic processing is a powerful but expensive method: users won't use their minds without a reason, but it's hard to provide them with a reason. An analogy works best as an excuse, no matter how it is presented, as a metaphor for an interface, or as an epithet in documentation.

The price of remembering. It is common that the use of fiberboard is quite expensive. It is impossible to argue with this, since the statement contains the word "enough", which has an extremely vague meaning.

In fact, everything is complicated. Different concepts come to mind with different speed, words, for example, are remembered faster than numbers, and visual images - faster than words. The sample size has a very strong effect, that is, recalling one value out of ten possible is obtained faster than out of a hundred possible. Finally, the frequency of recall affects the speed of recall (i.e., the speed of recall is strongly influenced by training).

When designing an interface, it is convenient to use the following rule. For ordinary users who do not have the skills to extract information from fiberboard inherent in the designed system, the load on the fiberboard should be reduced; for experienced users who have developed these skills, access to fiberboard can be faster than any other way of searching for information.

It is important, however, to be aware that for experienced fiberboard users, being fast is not necessarily preferable. For example, if the task is to reduce the number of errors, the menu will be more efficient than, say, command line, since it will not allow you to give a knowingly wrong command.

There is a strategy for obtaining information from memory, as well as a strategy for helping to retain information in long-term memory. Mnemonics- this is the attachment of semantic meanings to memorized information (example with a phone number). People train themselves to memorize a very large amount of information by creating internal visual "clues" that help remember each piece of information separately. When working with this information, the "clue" helps to recover each "piece" of information and easily navigate between them.

Since accessing long-term memory is difficult, computer interfaces should be designed with this in mind and should be as helpful as possible. There are two main methods for working with information: recognition and memory recovery.

Why force users to remember information if they already know it? Why not give a list or menu of data and allow it to be recognized? Recovery in memory involves trying to recognize information without any help. Recognition implies an attempt to recall information using some kind of relationship (Compare: action through the menu and using a keyboard shortcut).

User interface design is based on the knowledge of how a person perceives and perceives. One of the most important tasks of the interface: to reduce the user's confidence in their own memory and to use the advantages of the computer to support human weaknesses.

	Strengths	Weak sides
People	- pattern recognition - attention switching - infinite long-term memory capacity - rich multi-code long-term memory - learning ability	- short-term memory with low capacity - fast data loss from short-term memory - slow data processing - errors - difficult access to long-term memory
Computers	- memory with large capacity- long-term memory - high processing speed - error-free processing - fault-free memory access	- easy comparison to benchmark - limited learning ability - limited long-term memory capacity - limited data integration