Inner memory includes all kinds of storage devices located on the motherboard. Part internal memory includes the following devices.
RAM or RAM (RAM) serves to store instructions and data needed by the processor to perform operations. This memory allows you to access any cell, therefore it is also called memory. Withrandom access ( RAM - memory) . Differs in high speed. The main disadvantage is the disappearance of data after turning off the power.
Cache memory or scratchpad memory – a very fast storage device that stores current data and provides it to the processor when needed. Differs in considerable speed. The disadvantages include a more complex manufacturing process, and, accordingly, a high cost.
Special Memory has several components:
read-only memory or read-only memory (ROM) read-only( ROM -memory ), non-volatile, the content of the memory is "sewn up" during manufacture and does not change during operation;
reprogrammable constant memory is rewritable, non-volatile, contains a basic input / output system (BIOS), which is necessary for automatic testing and loading of the operating system when the computer is turned on;
battery powered memory is a type of permanent memory and is used to store time, date and system configuration data;
video memory is designed to store video data that is available simultaneously to the processor and monitor.
External memory includes devices (drives) located off the motherboard and having media with different principle actions.
Carrier - it is a physical medium or a material object whose structure is used to store data in a disk magnetic drive, for example, it is a ferromagnetic layer on the surface of a disk.
Drives - are storage devices for long-term storage large amounts of data without power. Depending on the fundamental basis of the carrier, magnetic, optical and semiconductor type drives are distinguished.
Magnetic disk drive (hard disk, hard drive) is the main device for long-term storage of data and programs based on the magnetic principle of recording. The magnetic drive is assembled in a sealed case, inside which several disks are coaxially located. Each disk is covered with a ferromagnetic layer on both sides, the disk surface is divided into tracks and sectors (formatted). The disk rotates relative to the magnetic heads that store and read data. Data is stored in the form of a track of microscopic magnetized areas - domains, the magnetization of which is recorded as a sequence of logical units.
Optical drive ( CD - ROM ) – this is a device for long-term storage of large amounts of data recorded at a higher density than on a magnetic disk. The principle of operation is based on reading data using a laser beam that is reflected from the surface of the disk. The metallized surface of a compact disc (CD), on which a spiral track is applied, acts as a data carrier. A digital recording on a CD track is stored as a sequence of sections called pit (point, depression) and land (surface). The logical unit is encoded by the transition between the recess and the surface. The sequence of recesses in which the record is encoded is applied either by stamping from a matrix or by cauterizing sections of the track with a laser beam.
Compact discs are made of polypropylene, on the surface of which a multi-layer coating is applied, including the so-called active layer. Depending on the ratio of coatings, active layer material, track width, CDs are distinguished different device and appointments:
CD-R - disks that allow you to perform a single write and an unlimited number of reads;
CD-RW – disks for reusable recording, rewriting and reading data;
DVD – discs for re-recording with increased data density.
The main disadvantage of disk drives is expressed in the presence of an electromechanical drive, which limits the reliability, resource, weight and size of devices.
Flash-card - device semiconductor type for long-term non-volatile data storage, which is implemented on the basis of a memory chip. An array of semiconductor cells located inside the microcircuit acts as a data carrier. The principle of operation of a semiconductor storage device is based on the recording and erasing of an electric charge in a cell of a semiconductor structure. Due to its compactness, low cost, mechanical strength and low power consumption, the flash drive is increasingly used in computer technology and successfully replaces memory devices of previous generations.
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| Purpose and device of the computer. computer memory
Lesson 6
Purpose and device of the computer. Principles of organization of internal and external memory
§5. Purpose and device of the computer
§6. computer memory
Purpose and device of the computer
Main topics, paragraph:
What is common between a computer and a person;
- what devices are included in the computer;
- what is data and program;
- Von Neumann principles.
Issues under study:
What do computers and humans have in common?
With this lesson, we begin our acquaintance with the computer. For computer science, a computer is not only a tool for working with information, but also an object of study. You will learn how a computer works, what kind of work you can do with it, which ones exist for this. software.
Since ancient times, people have sought to make their work easier. For this purpose, various machines and mechanisms were created that enhance the physical capabilities of a person. An electronic computer (in modern terminology - a computer) (Fig. 2.1) was invented in the middle of the 20th century to enhance the capabilities of a person's mental work, that is, work with information.
It is known from the history of science and technology that man “peeped” the ideas of many of his inventions in nature.
For example, back in the 15th century, the great Italian scientist and artist Leonardo da Vinci studied the structure of the bodies of birds and used this knowledge to design aircraft.
The Russian scientist N. E. Zhukovsky, the founder of aerodynamics, also studied the mechanism of bird flight. The results of these studies are used in the calculations of aircraft structures.
Does a computer have a prototype in nature? Yes! Man himself is such a prototype. Only the inventors sought to transfer to the computer not the physical, but the intellectual capabilities of a person.
According to its purpose, the computer is universal technical means for the work of a person with information.
According to the principles of the device, a computer is a model of a person working with information..
What devices are included in the computer
Human information activity is divided into components:
Reception (input) of information;
memorization of information (storage in memory);
thinking process (information processing);
transmission (output) of information.
The computer includes devices that perform similar functions:
Input Devices;
memory devices - memory;
processing device - processor;
output devices.
In the course of computer operation, information enters memory through input devices; the processor extracts the processed information from the memory, works with it and places the processing results in the memory; the results obtained through the output devices are reported to the person.
Most often, the keyboard is used as the input device, and the monitor or printer (printing device) is used as the output device.
What is data and program
And yet, one cannot identify the "mind of a computer" with the mind of a person. The most important difference is that the work of the computer is strictly subordinated to the program embedded in it, while the person himself controls his actions.
Computer memory stores data and programs.
Data- this is the processed information presented in the computer memory in a special form.
Program is a description of the sequence of actions that a computer must perform to solve a given data processing task.
If information for a person is the knowledge that he possesses, then information for a computer is data and programs stored in memory. Data is the "declarative knowledge", programs are the "procedural knowledge" of the computer.
Von Neumann's principles
In 1946, the American scientist John von Neumann formulated the basic principles of the design and operation of computers. The composition of computer devices described above and the interaction between them is called the von Neumann architecture. The Neumann architecture is characterized by the presence of a single processor that controls the operation of all other devices. You have yet to become familiar with other von Neumann principles.
Briefly about the main
Computer is a software-controlled device for performing any kind of work with information.
The computer includes: processor, memory, input devices, output devices.
Stored in computer memory data and programs.
Computer works on programs created by man.
Questions and tasks
1. What human capabilities does a computer reproduce?
2. List the main devices that make up the computer. What is the purpose of each of them?
3. Describe the process of information exchange between computer devices.
4. What is a computer program?
5. What is the difference between data and program?
6. Prepare a report on the principles formulated by von Neumann.
computer memory
Main topics, paragraph:
Internal and external memory;
- the structure of the internal memory of the computer;
- program in computer memory;
- media and external memory devices.
Issues under study:
Computer as a model of a person working with information.
- Scheme of information exchange in a computer.
- Difference between program and data.
- The difference between internal and external computer memory.
- The principle of binary encoding of information.
- The structure of the internal memory of the computer, its properties.
- Media and external memory devices.
Internal and external memory
Working with information, a person uses not only his knowledge, but also books, reference books and other external sources. In Chapter I "Man and Information" it was noted that information can be stored in a person's memory and on external media. A person can forget the memorized information, and the records are stored more reliably.
The computer also has two types of memory: internal (operative) and external (long-term) memory.
Inner memory- This electronic device, which stores information while powered by electricity. When the computer is disconnected from the network, information from random access memory disappears. The program during its execution is stored in the internal memory of the computer.
The formulated rule refers to the Neumann principles. This rule is called the stored program principle.
External memory- these are various magnetic media (tapes, disks), optical discs, flash memory cards. Saving information on external media does not require constant power supply.
IN modern computers there is another type of internal memory called Read Only Memory - ROM. This is a non-volatile memory, information from which can only be read.
Figure 2.2 shows the composition of the computer devices. The arrows indicate the directions of information exchange.
The structure of the computer's internal memory
Computer devices perform certain work with information (data and programs). But how is the information itself represented in a computer? To answer this question, let's look inside the machine memory. The structure of the internal memory of a computer can be conditionally depicted as shown in Fig. 2.3.
The smallest unit of computer memory is called a bit of memory. In Figure 2.3, each cell represents a bit. You see that the word "bit" has two meanings: a unit of measurement for the amount of information and a particle of computer memory. Let us show how these concepts are related.
Each bit of memory can be stored in this moment one of two values: zero or one. The use of two characters to represent information is called a binary encoding.
Data and programs in computer memory are stored in binary form.
One character of a two-character alphabet carries 1 bit of information.
One bit of memory contains one bit of information.
The bit structure defines the first property of a computer's internal memory - discreteness. Discrete objects are made up of individual particles. For example, sand is discrete, as it consists of grains of sand. Bits are the grains of computer memory.
The second property of the computer's internal memory is addressability. Eight consecutive bits of memory form a byte. You know that this word also denotes a unit of quantity of information, equal to eight bits. Therefore, one byte of information is stored in one byte of memory.
In the internal memory of a computer, all bytes are numbered. The numbering starts from zero.
The sequence number of a byte is called its address.
The principle of addressability means that:
Writing information to memory, as well as reading it from memory, is performed at addresses.
Program in computer memory
Several consecutive bytes of memory form a memory cell whose address is the address of the least significant byte, that is, the byte with the smallest number. Figure 2.4 shows the principle of addressing using 4-byte memory cells as an example.
One memory cell can store one program instruction or data element processed by the program (for example, a number). A machine program is a set of instructions located in successive memory cells (Fig. 2.5).
Program team consists of the operational part - the operation code and the address part - the addresses of the location of the processed data in the memory. The opcode specifies the action the processor takes on command. The processor's job is to automatically execute a sequence of program commands until it ends (stop commands).
Media and external storage devices
External memory devices- These are devices for reading and writing information to external media. Information on external media is stored as files. You will learn more about files later.
The most important external memory devices in modern computers are magnetic disk drives(NMD), or disk drives.
The principle of magnetic recording was invented in the 1920s. Then acoustic tape recorders appeared, which made it possible to record speech, music on a magnetic tape, and then play the recorded sounds. The first type of external memory devices on computers were magnetic tape drives - analogues of acoustic tape recorders.
A modern NMD works similarly to a tape recorder. On the surface of the disk, covered with a thin ferromagnetic layer, is written binary code: magnetized area - one, non-magnetized - zero. When read from disk, this entry is converted to zeros and ones in internal memory bits.
A recording head is brought to the magnetic surface of the disk (Fig. 2.6), which can move along the radius. During NMD operation, the disk rotates. In each fixed position, the head interacts with the circular track. Binary information is recorded on these concentric tracks.
Another type of external media are optical discs (their other name is laser discs). They use not a magnetic, but an optical-mechanical method of recording and reading information.
First, laser discs appeared, on which information is recorded only once. It cannot be erased or overwritten. Such disks are called CD-ROM - Compact Disk-Read Only Memory, which means "compact disk - read only". Later, rewritable laser discs, CD-RWs, were invented. On them, as well as on magnetic media, stored information can be erased and recorded again.
Media that a user can remove from a drive is called removable media.
Of the removable media, laser discs of the DVD type (Digital Versatile Disk - a universal digital disk) have the largest information capacity. They are sometimes called videodiscs. The amount of information stored on a DVD is measured in gigabytes. Movies recorded on DVD can be viewed on a computer, just like on TV.
A relatively new type of external memory device is flash memory. The flash memory device is connected to the computer via a universal USB connector.
Briefly about the main
The computer consists of internal and external memory.
The executable program is stored in the internal memory (stored program principle).
Information in computer memory is in binary form.
The smallest unit of a computer's internal memory is a bit. One bit of memory stores one bit of information: the value 0 or 1.
Eight consecutive bits form a byte of memory. The bytes are numbered starting from zero. The sequence number of a byte is called its address.
In the internal memory, information is written and read at addresses.
A machine program is a set of instructions located in consecutive memory cells.
External memory: magnetic disks; optical (laser) disks - CD, DVD; flash memory.
Questions and tasks
1. Try to explain why a computer needs two types of memory: internal and external. Prepare a message.
2. What is the stored program principle?
3. What is the property of discreteness of the internal memory of a computer?
4. What are the two meanings of the word "bit"? How are they related?
5. What is the addressability property of the computer's internal memory?
6. What is a machine program? What information is contained in a program command?
7. Name your computer's external storage devices and take photos of them.
8. What types optical discs You know?
Electronic application for the lesson
Download lesson materials
Description of the presentation on individual slides:
1 slide
Description of the slide:
Purpose and device of the computer. Principles of organization of internal and external memory.
2 slide
Description of the slide:
3 slide
Description of the slide:
MEMORY CHARACTERISTICS: Capacity - the maximum amount of information that "fits" in various devices memory; The speed of access to information; Method of access to information - direct or sequential; The principle of writing-reading - magnetic or optical
4 slide
Description of the slide:
MEMORY TYPES External Internal VZU (external storage devices) is designed for long-term storage of user information. It can be updated, deleted unnecessary. This type of memory is not designed to store user information. It is used by the system itself and ensures its functioning. Floppy disks Hard disks Compact discs Flash-based devices Random access memory (RAM) Cache memory Read-only memory
5 slide
Description of the slide:
EXTERNAL MEMORY The main function of the computer's external memory is the ability to store a large amount of information (programs, documents, audio and video clips, etc.) for a long time. A device that provides writing / reading information is called a drive or a disk drive, and information is stored on media (for example, floppy disks). Information on external media has a file organization. A file is information stored on an external medium and has its own name.
6 slide
Description of the slide:
Floppy disks A floppy disk, also known as a floppy disk or floppy disk, is a round flexible plate with a magnetized layer inserted into a plastic case. The floppy disk rotates in a plastic case, protected by two spacers to reduce friction. The principle of recording on diskettes is magnetic. Access to information is direct. In floppy disks (3.5 inches) there is a mode for protecting information from erasure and writing, which is carried out by switching the corresponding switch on a plastic envelope. A standard floppy disk contains 1.44 MB of information. Floppy disks need very careful storage. They cannot be wetted, beaten, treated carelessly.
7 slide
Description of the slide:
HARD MAGNETIC DISKS HDD(HDD - Hard Disk Drive) refers to non-replaceable disk magnetic drives. Hard magnetic disks are several dozens of disks placed on the same axis, enclosed in a metal case and rotating at a high angular speed. The speed of writing and reading information from hard drives quite large (about 133 MB / s) due to the fast rotation of the disks (7200 rpm). Hard disks use rather fragile and miniature elements. To preserve the information and performance of hard drives, it is necessary to protect them from shocks and sudden changes in spatial orientation during operation.
8 slide
Description of the slide:
LASER DRIVES AND DISKS Laser disk drives use the optical principle of reading information. On laser discs CD (CD - Compact Disk, compact disc) and DVD (DVD - Digital Video Disk, digital video disc) information is recorded on one spiral track (like on a phonograph record), containing alternating sections with different reflectivity. The laser beam falls on the surface of the rotating disk, and the intensity of the reflected beam depends on the reflectivity of the track section and takes on the values 0 or 1.
9 slide
Description of the slide:
FLASH-MEMORY DEVICES Flash-memory is a non-volatile type of memory that allows you to write and store data in microcircuits. Devices based on flash-memory do not have moving parts, which ensures high data safety when used in mobile devices. Flash memory is a microchip placed in a miniature package. To write or read information, the drives are connected to a computer via a USB port. The information capacity of memory cards reaches 16 GB. Memory cards
10 slide
Description of the slide:
INTERNAL MEMORY The devices that make up the internal memory are located on the "motherboard" in system unit. This type of memory is not designed to store user information. She's used computer system. Properties of internal memory: Discreteness; Discrete objects are made up of individual particles. Memory is made up of individual cells called bits. Addressability. Entering information into memory, as well as retrieving it from memory, is carried out at addresses.
11 slide
Description of the slide:
RAM large volume, directly connected to the processor and intended for writing, reading and storing executable programs and data processed by these programs.
Lesson 6 Principles of organization of internal and external memory.
Issues under study:
Computer as a model of a person working with information.
Scheme of information exchange in a computer.
Difference between program and data.
The difference between internal and external computer memory.
The principle of binary encoding of information.
The structure of the internal memory of the computer, its properties.
Media and external memory devices.
Analogy between man and computer.
According to its purpose, a computer is a universal technical tool for a person to work with information. Computer memory stores data and programs.
Composition of computer devices
Data and programs are stored in the general memory of the computer
Data and programs are stored in the computer memory in the form of a binary code.
Writing information to memory, as well as reading it from memory, is performed at addresses
Von Neumann principles
The internal memory of the computer.
Internal memory consists of particles - bits. One bit of memory stores one bit of information.
Byte of memory - the smallest addressable part of the internal memory (1 byte = 8 bits)
All bytes are numbered starting from 0
Byte number - memory byte address
The processor accesses memory by addresses
Media and external storage devices
Magnetic memory - streamers and disk drives;
Optical memory - CD, DVD (ROM, R, RW);
Electronic memory - memory cards, flash drives.
Verification work.
1. Which of the following characteristics apply to operational, and which - to external memory?
a) It is volatile.
b) Its volume is measured in tens and hundreds of gigabytes.
c) Used for long-term storage of information.
d) Its volume is measured in hundreds of megabytes or several gigabytes.
e) Faster access.
f) Used for temporary storage of information.
g) Slower access.
Which Memory V bytes will take the next binary code: ? Explain your answer.
Text in volume 1024 bits located in random access memory, starting from byte number 10 . What will be the address last byte, which is occupied by the given text?
List at least five devices you know external memory.
What difference disks CD- ROM, CD- RW And CD- R?
Homework. P. 5.6
Lesson Objectives: Learning new material on the topic “Principles of organizing internal and external computer memory.”
Lesson objectives:
Educational:
- to acquaint students with the information structure of internal and external memory;
- introduce the basic concepts of the topic, the classification and purpose of external memory devices.
Developing:
- to carry out propaedeutics of the formation of intellectual and informational skills;
- develop independence in thinking and learning activities.
Educational:
- develop interest in the subject;
- educate the culture of working at a computer - “user culture”;
- to cultivate responsibility, independence, respect for each other.
Lesson type: combined - a lesson explaining new material
Forms, educational work, students: frontal work, work in pairs, individual work at the computer.
Means of education:
textbooks: Semakin I. G., Zalogova L. A., Rusakov S. V., Shestakova L. V. Informatics: Basic course for 7 - 9 cells. - M.: Laboratory Basic Knowledge, 1998.
Semakin I. G., Varaksin G. S. Structured abstract of the basic course. - M.: Basic Knowledge Laboratory, 2001.
CDs: Computer Anatomy - 2
hardware and software:
Personal computers;
MS Windows OS application - PowerPoint program;
presentation on the topic of the lesson “Internal and external memory of a computer”;
projector.
Lesson steps:
I. Organizational part.
II. Presentation of the topic and objectives of the lesson. Explanation of work on the score sheet.
III. Checking homework. Programmed control of the studied material (test).
IV. Updating of basic knowledge.
V. Explanation of new material.
- Problematic situation. "Computer Message".
- information structure of internal memory.
- information structure of external memory.
- external memory devices.
VI. Checking students' understanding of new material.
VII. Summing up the lesson.
DURING THE CLASSES
I. Organizational part.
The teacher greets the students, notes the absence in the journal, checks the readiness of the students for the lesson.
II. Presentation of the topic and objectives of the lesson.
