COMPUTER  HARDWARE 

 A computer is a combination of two terms Hardware and Software. The physical components of a computer are called hardware. Pieces of hardware may be categorized according to the functions each performs: input, process, output, and storage. Your PC (Personal Computer) is a system, consisting of many components. Some of those components, like Windows XP, and all your other programs, are software. Software is the source of interaction between the user and the computer. It represents programs, collection of several sets of instructions, which allow the hardware to run properly. The stuff you can actually see and touch, and would likely break if you threw it out a fifth-story window, is hardware. 

 Computer Hardware Hardware of a computer is made up of complex electronic circuits. For a user the details of the circuitry are not important. However, the hardware units with which a user has to interact must be clearly understood. For convenience, the hardware of a computer can be classified in the following categories:

 1. Input Devices

 2. Output Devices

 3. Central Processing Unit (CPU)

 4. Memory or Storage 

5. Motherboard 

Let us discuss each of these hardware components:

 1. Input Devices: The form in which data is available to a user is not always in the same formas is accepted by computer hardware. Input devices are hardware equipment that receive data and instructions from users, convert the data and instructions into a form that can be processed by the computer and passes the same to the computer. Hence, if you have to enter employees’ names into the computer you do not have to write it on a piece of paper and shove the paper inside the computer. You will need some input device for this. Example: A keyboard is an example of input device.

 2. Output Devices: The result, produced by a computer after processing, is not always in user readable form. An output device is hardware equipment that translates this non-readable result into a form understood by the users. Example: A VDU (Visual Display Unit) or monitor is an example of output device.

 3. Central Processing Unit (CPU): Central processing unit is to computer what brain is to our body. It is the master organ of a computer. No computer can exist without a CPU. It is composed of two simpler hardware units - Arithmetic Logic Unit (ALU) and Control Unit (CU). CU controls all the activities of other hardware units while ALU performs all the calculations. Computer CPUs are very fast in their calculations and swift in control.

 4. Memory or Storage: This hardware is the place where a computer stores all the data and instructions given to it. The results of the processing are also stored here. A computer has many types of memories. Some memories are directly connected to the CPU and are extremely fast as far as storage and retrieval of data is concerned. These memories are called primary memory - RAM (Random Access Memories) and ROM (Read Only Memories) belong to this category of memories. The CPU takes data and instructions stored only in the primary memories. 

 Primary memories are also of various types. The one that looses its contents when power is switched off is known as volatile memory such as RAM. Some memories retain the data and instructions stored on them even after the power is switched off such as ROM. These memories are known as non-volatile memories.

 Secondary storage devices are placed outside the system unit and can be carried from one system to another allowing portability of data and instructions. Floppy disks or diskettes, hard disks and CD-ROM are some of the secondary storage devices. Input devices, output devices and secondary storage devices are not directly connected to the CPU and hence are known as peripheral devices or simply peripherals.

5. Motherboard: Motherboard, also called as System Board, is the most important hardware Notes component of a microcomputer. Motherboard is so called as all the other boards (printed circuit boards having chips or other electronic components) of the computer are connected to this board, hence it is like the mother of all other boards.

 Now we will discuss the components of computer hardware in detail. 

 Central Processing Unit Central Processing Unit (CPU) is the main component or “brain” of a computer, which performs all the processing of input data. Its function is to fetch, examine and then execute the instructions stored in the main memory of a computer. In microcomputers, the CPU is built on a single chip or Integerated Circuit (IC) and is called as a Microprocessor. The part of a computer (a microprocessor chip) that does most of the data processing, the CPU and the memory form the central part of a computer to which the peripherals are attached. The Central Processing Unit (CPU) is the part of a computer that interprets and carries out the instructions contained in the software.

 The CPU consists of the following distinct parts: 

 Arithmetic Logic Unit (ALU): The arithmetic and logic unit of CPU is responsible for all arithmetic operations like addition, subtraction, multiplication and division as well as logical operations such as less than, equal to and greater than. Actually, all calculations and comparisons are performed in the arithmetic logic unit. 

 Control Unit (CU): The control unit is responsible for controlling the transfer of data and instructions among other units of a computer. It is considered as the “Central Nervous System” of computer, as it manages and coordinates all the units of the computer. It obtains the instructions from the memory, interprets them and directs the operation of the computer. It also performs the physical data transfer between memory and the peripheral device. 

 Registers: Registers are small high speed circuits (memory locations) which are used to store data, instructions and memory addresses (memory location numbers), when ALU performs arithmetic and logical operations. Registers can store one word of data (1 word = 2 bytes & 1 byte = 8 bits.) until it is overwritten by another word. Depending on the processor’s capability, the number and type of registers vary from one CPU to another. Registers can be divided into six categories viz. General Purpose Registers, Pointer Registers, Segment Registers, Index Registers, Flags Register and Instruction Pointer Register, depending upon their functions. The detailed functions of each and every register is beyond the scope of this book. 

 Buses: Data is stored as a unit of eight bits (BIT stands for Binary Digit i.e. 0 or 1) in a register. Each bit is transferred from one register to another by means of a separate wire. This group of eight wires, which is used as a common way to transfer data between registers is known as a bus. In general terms, bus is a connection between two components to transmit signal between them. Bus can be of three major types viz. Data Bus, Control Bus and Address Bus. The data bus is used to move data, address bus to move address or memory location and control bus to send control signals between various components of a computer. 

 Clock: Clock is another important component of CPU, which measures and allocates a fixed time slot for processing each and every micro-operation (smallest functional operation). In simple terms, CPU is allocated one or more clock cycles to complete a micro-operation. CPU executes the instructions in synchronization with the clock pulse.The clock speed of CPU is measured in terms of Mega Hertz (MHz) or Millions of Cycles per second. The clock speed of CPU varies from one model to another in the range 4.77 MHz (in 8088 processor) to 266 MHz (in Pentium II). CPU speed is also specified in terms of Millions of Instructions Per Second (MIPS) or Million of Floating Point Operations Per Second  (MFLOPS).

 

 CCTV ( Closed-Circuit Television )

It is a device to use live video capture device. It first used in Germany 1942 and invented by Walter Bruch . Now a days it is used in so many places like road , airports , school , business places and etc. 

                                                          Types of CCTV camera 

Dome camera - Dome Cameras are named after their shape is typically used for indoor security systems. The dome shape of these cameras allows them to be inconspicuous because it is hard to tell the direction the cameras are facing; however, being still visible to the eyes. They are widely used in retail spaces. Since they are installed on the ceiling of the room, they are mostly vandal proof. Some dome cameras are designed with infrared illuminator , which enable them to capture videos in low light conditions.  

Bullet camera - Bullet Cameras have a long and tapered cylinder-like design that resembles an oversized ammo cartridge. They are mostly used outdoors, especially in areas where long viewing is necessary. However, they can be used indoors where the long viewing is required, like backyards and parking lots. They are installed inside protective casings and are typically weatherproof. Most bullet cameras come with a fixed length that allows the angle of view of up to 80 degrees. A bullet camera is usually fitted with a fixed or varifocal lens. 

 Day/Night CCTV Camera

These types of CCTV cameras can be used in both poorly lit and standard environments. Mostly used outdoors, these surveillance units have a wide dynamic range and can function under direct sunlight, glare, or reflections. They are used 24×7, and these cameras do not require an infrared illuminator as they come with an extra sensitive imagining chip, which is used in the dark. 

 Network/IP CCTV Camera

The IP camera can transmit recordings over the internet. It may or may not require a wire connection. Yes, it also works on wireless technology. In comparison to the analog camera, it is easy to install. It is possible to send recording over a far distance without requiring any power boost using a cable. 

What is computer ? 

Computer is a electronics device which can store data and information. Its takes data and instruction from user through input device and process the data and instruction through processing device and final its give answer to the user through output device.   

COMPUTER stand for :- 

C - common 

O - operating

M - machine 

P - particularly

U - used for 

T - technical

E - education 

R - research 

Basic Terms

 – an electronic device that controls the flow of electrons in a vacuum. It used as a switch, amplifier, or display screen in many older model radios, televisions, computers, etc.

 

 – an electronic component that can be used as an amplifier or as a switch. It is used to control the flow of electricity in radios, televisions, computers, etc.

 

 – a small electronic circuit printed on a chip (usually made of silicon) that contains many its own circuit elements (e.g. transistors, diodes, resistors, etc.).

 

 – an electronic component held on an integrated circuit that contains a computer’s central processing unit (CPU) and other associated circuits.

 

 – It is often referred to as the brain or engine of a computer where most of the processing and operations take place (CPU is part of a microprocessor).

 

 – a cylinder coated with magnetic material, on which data and programs can be stored.

 

 – uses arrays of small rings of magnetized material called cores to store information.

 

 – a low-level programming language comprised of a collection of binary digits (ones and zeros) that the computer can read and understand.

 

Assembly language is like the machine language that a computer can understand, except that assembly language uses abbreviated words (e.g. ADD, SUB, DIV…) in place of numbers (0s and 1s).

 

 – a physical device that is used to store data, information and program in a computer.

 

 – an area of computer science that deals with the simulation and creation of intelligent machines or intelligent behave in computers (they think, learn, work, and react like humans).

First Generation of Computers

Classification of generations of computers

The evolution of computer technology is often divided into five generations.

Five Generations of Computers

Generations of computers	Generations timeline	Evolving hardware
First generation	1940s-1950s	Vacuum tube based
Second generation	1950s-1960s	Transistor based
Third generation	1960s-1970s	Integrated circuit based
Fourth generation	1970s-present	Microprocessor based
Fifth generation	The present and the future	Artificial intelligence based

The main characteristics of first generation of computers (1940s-1950s)

• Main electronic component – vacuum tube
• Main memory – magnetic drums and magnetic tapes
• Programming language – machine language
• Power – consume a lot of electricity and generate a lot of heat.
• Speed and size – very slow and very large in size (often taking up entire room).
• Input/output devices – punched cards and paper tape.
• Examples – ENIAC, UNIVAC1, IBM 650, IBM 701, etc.
• Quantity – there were about 100 different vacuum tube computers produced between 1942 and1963.

Second Generation of Computers

The main characteristics of second generation of computers (1950s-1960s)

• 

  Main electronic component – transistor

• Memory – magnetic core and magnetic tape / disk
• Programming language – assembly language
• Power and size – low power consumption, generated less heat, and smaller in size (in comparison with the first generation computers).
• Speed – improvement of speed and reliability (in comparison with the first generation computers).
• Input/output devices – punched cards and magnetic tape.
• Examples – IBM 1401, IBM 7090 and 7094, UNIVAC 1107, etc.

Third Generation of Computers

The main characteristics of third generation of computers (1960s-1970s)

• Main electronic component – integrated circuits (ICs)
• Memory – large magnetic core, magnetic tape / disk
• Programming language – high level language (FORTRAN, BASIC, Pascal, COBOL, C, etc.)
• Size – smaller, cheaper, and more efficient than second generation computers (they were called minicomputers).
• Speed – improvement of speed and reliability (in comparison with the second generation computers).
• Input / output devices – magnetic tape, keyboard, monitor, printer, etc.
• Examples – IBM 360, IBM 370, PDP-11, UNIVAC 1108, etc.

Fourth Generation of Computers

The main characteristics of fourth generation of computers (1970s-present)

• Main electronic component – very large-scale integration (VLSI) and microprocessor.
• VLSI– thousands of transistors on a single microchip.
• Memory – semiconductor memory (such as RAM, ROM, etc.)
  • RAM (random-access memory) – a type of data storage (memory element) used in computers that temporary stores of programs and data (volatile: its contents are lost when the computer is turned off).
  • ROM (read-only memory) – a type of data storage used in computers that permanently stores data and programs (non-volatile: its contents are retained even when the computer is turned off).
• Programming language – high level language (Python, C#, Java, JavaScript, Rust, Kotlin, etc.).
  • A mix of both third- and fourth-generation languages
• Size – smaller, cheaper and more efficient than third generation computers.
• Speed – improvement of speed, accuracy, and reliability (in comparison with the third generation computers).
• Input / output devices – keyboard, pointing devices, optical scanning, monitor, printer, etc.

• Network – a group of two or more computer systems linked together.
• Examples – IBM PC, STAR 1000, APPLE II, Apple Macintosh, etc.

Fifth Generation of Computers

The main characteristics of fifth generation of computers (the present and the future)

• Main electronic component: based on artificial intelligence, uses the Ultra Large-Scale Integration (ULSI) technology and parallel processing method.
  • ULSI – millions of transistors on a single microchip
  • Parallel processing method – use two or more microprocessors to run tasks simultaneously.
• Language – understand natural language (human language).
• Power – consume less power and generate less heat.
• Speed – remarkable improvement of speed, accuracy and reliability (in comparison with the fourth generation computers).
• Size – portable and small in size, and have a huge storage capacity.
• Input / output device – keyboard, monitor, mouse, trackpad (or touchpad), touchscreen, pen, speech input (recognise voice / speech), light scanner, printer, etc.
• Example – desktops, laptops, tablets, smartphones, etc.

The computer – this amazing technology went from a government/business-only technology to being everywhere from people’s homes, work places, to people’s pockets in less than 100 years.