Computer overview and its structure

Computer - an electronic device, operating under the control of instructions stored in its own memory that can accept data (input), process the data according to specified rules, produce information (output), and store the information for future use

Functionalities of a computer:

Any digital computer carries out following five functions:

1. Takes data as input
2. Stores the data/instructions in its memory and use when required
3. Processes the data and converts it into useful information
4. Generates the output
5. Controls all the above four steps

Computer components: HARDWARE and SOFTWARE

HARDWARE

Computer hardware is the collection of physical elements that constitutes a computer system.

Computer hardware refers to the physical parts or components of a computer such as: monitor, mouse, keyboard, computer data storage, hard drive disk (HDD), system unit (graphic cards, sound cards, memory, motherboard and chips), etc. all of which are physical objects that can be touched.

Input Devices:

Any peripheral piece of computer hardware equipment to provide data and control signals to an information processing system such as a computer or other information appliance (прибор).

Translate data from form that humans understand to one that the computer can work with.

Most common are keyboard and mouse.

Central Processing Unit (CPU):

Brain of a computer.

Responsible for all functions and processes.

The most important element of a computer system.

The CPU is comprised of three main parts:

Arithmetic Logic Unit (ALU): Executes all arithmetic and logical operations.

Control Unit (CU): Controls and co-ordinates computer components.

1. Read the code for the next instruction to be executed.

2. Increment (увеличение, возрастание) the program counter so it points to the next instruction.

3. Read whatever data the instruction requires from cells in memory.

4. Provide the necessary data to an ALU or register.

5. If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to perform the requested operation.

Registers: Stores the data that is to be executed next, "very fast storage area".

Primary Memory:

RAM (Random Access Memory) data on a temporary basis, so that it can be promptly (сразу же, быстро) accessed by the Permanent form of storage.

- Memory scheme within the computer system responsible for storing processor as and when needed.

- Volatile (изменчивый, непостоянный) in nature, which means that data will be erased once supply to the storage device is turned off.

- Stores data randomly and the processor accesses these data randomly.

- Considered "random access" because you can access any memory cell directly if you know the row and column that intersect at that cell.

Рэм текущая память, используемая при работе с программой. И только нажимая сохранить, мы переносим информацию из временной памяти, временного хранилища, на жёсткий диск.

ROM (Read Only Memory):

- Permanent from of storage

- Stays active regardless of whether power supply to it is turned on or off.

- ROM devices do not allow data stored on them to be modified.

- То, что уже стоит и не меняется, можно только их прочесть (игровые консоли)

Secondary Memory:

- Stores data and programs permanently; it’s retained (удерживает) after the power is turned off. На деле не вторая память, просто другой вид. По большей части используется для хранения информации.

Hard drive (HD): Often called a "disk drive," "hard drive," or "hard disk drive," that store and provides relatively quick access to large amounts of data on an electromagnetically charged surface or set of surfaces.

Optical Disk: Disk drive that uses laser light as part of the process of reading or writing data to or from optical discs. Compact discs, DVDs, and Blu-ray discs are common types of optical media.

Flash Disk: A storage module made of flash memory chips.A Flash disks have no mechanical platters or access arms, but the term "disk" is used because the data are accessed as if they were on a hard drive. Флешки.

Output Devices:

Any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) which converts the electronically generated information into the format human can recognize. (монитор, принтер, мультимедия прицессор)

Software

Software is a generic term for organized collections of computer data and instructions.

Often broken into two major categories: system software that provides the basic non-task-specific functions of the computer, and application software which is used by users to accomplish specific tasks.

Используя компьютер, мы всегда используем софтвэр, но нет нужды точно знать что как и в какой момент работает.

System software

Responsible for controlling, integrating, and managing the individual hardware components of a computer system so that other software and the users of the system see it as a functional unit without having to be concerned with the low-level details such as transferring data from memory to disk, or rendering text onto a display.

Generally, system software consists of an operating system and some fundamental utilities such as disk formatters, file managers, display managers, text editors, user authentication (login) and management tools, and networking and device control software.

Application software

Used to accomplish specific tasks other than just running the computer system.
Application software may consist of:

A single program, such as an image viewer

A small collection of programs (often called a software package) that work closely together to accomplish a task, such as a spreadsheet or text processing system

 

A larger collection (often called a software suite) of related but independent programs and packages that have a common user interface or shared data format, such as Microsoft Office, which consists of closely integrated word processor, spreadsheet, database, etc.

A software system, such as a database management system, which is a collection of fundamental programs that may provide some service to a variety of other independent applications.

Storage

Classification of computer:

Computers can generally be classified by size and power as follows, though there is considerable overlap:

Personal computer: A small, single-user computer based on a microprocessor. In addition to the microprocessor.

Workstation: A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

Minicomputer: A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.

Mainframe: A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.

Supercomputer: An extremely fast computer that can perform hundreds of millions of instructions per second. (Supercomputer Example –Watson Artificial intelligence computer system capable of answering questions posed in natural language
Built by IBM. Can process 500 gigabytes, the equivalent of a million books per second)

Hand-held devices
– Smartphones
– PDA,Tablet
– Game Boy, Nintendo DS, PlayStation Portable (PSP)

Video game consoles – Wii, Xbox, PS3

Pc- для мелких повседневных нужд, сейчас можно использовать и как воркстэйшен

History of Computer

 First Generation (~1940 to ~1956)

- In 1946, ENAIC (Electronic Numerical Integrator and Calculator) was developed by J. Presper Eckert and John Manuchly at University of Pennsylvania.

- 18,000 vacuum tubes; $500,000; 30 tons; 30 by 50 foot; large amount of heat; very slow.

- ENIAC использовали для расчёта ракурса пушек. Всё было сделано в связи со второй мировой

Second generation (~1956 to ~1963)

- Vacuum tubes replaced by transistors

- Speed / performance improved

- Size, price, and heat reduced

- 2 поколение. Для использования транзисторов использовали силикон. И даже поэтому силиконовая аллея называется силиконовой.

Third generation (~1964 to ~1971)

- Transistors replaced by IC’s (Integrated Circuits — fabrication of thousands electronic components on single silicon chip)

- Drastic reduction in the size of computer

- Speed / performance was higher

- Heat reduced

- 3 поколение. Гораздо меньше. Вместо этих огромных шкафов теперь всё помещалась в одну board

Fourth generation (~1972 to present)

- Lower cost, smaller size and higher performance

- The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.

- 4 поколение. Всё в одном маленьком силиконовом чипе — микропроцессор

Fifth generation (present and beyond)

Fifth generation computing devices, based on artificial intelligence, are still in development.

Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come.

The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

2019.4.15

Programming

Programming/coding is the act of instructing computers to carry out tasks So then, what is a computer program? A computer program is a sequence (последовательность) of instructions that the computer executes.