Basics of Computers Long Answer Type Questions Part 2
Define Computer? Explain different types of Computer
Computer is an Electronic Device, Which stores data, process it and gives the result consistently, accurately at very high speed according to our instruction. The word computer is derived from the word “Compute”. It means perform or calculate. That’s way, the computer is also called as calculating device. The computers can be broadly classified into three types namely a) Analog Computers, b) Digital Computers, and c) Hybrid computers.
a) Anglos Computers: The analog computer operate by measuring instead of counting. The analog computer works on the supply on continuous electrical signals. The display is also continuous and its output is in the form of graphs.
In Analog Computer, the input data is a continuously changing electrical or non-electrical information. Computations are carried out with physical quantities such as Voltage, Length, Current, Temperature etc. The device measuring such quantities are called analog devices. The advantage of analog computer is that all calculation take place in parallel and hence it is very fast. It is used for engineering and scientific application. But their accuracy is poor as compared to digital computer.
- It operates by measuring
- It requires by measuring.
- It function on continuously varying quantity
- The output is usually represented in the form of graph.
- The calculations are first converted into equations and later converted into electrical signals.
- The accuracy of the output is poor
- It has limited memory space
- It is not versatile i.e. it has limited applications
- Speed is very low
- These computers are-not suitable for business and industry.
- Examples, Electronic weighing scale, patients heart beat, blood pressure, temperature.
b) Digital Computers: As the name implies, the digital computer with quantities represented as digits. In digital computer, both numeric and non-numeric informations are represented as string of digits.
In Digital Computer, the input data is discrete in nature. It is represented by binary notation in the form of 0’s and l’s. Digital computers are much faster than analog computers and are more accurate. Digital computers are largely used for business and scientific applications.
The basic operation performed by a digital computer is addition. Hence, the other operations such as multiplication, division, subtraction and exponentiation are first changed into “Addition and then compute”.
- It operates by Counting
- It functions on discrete numbers
- The calculations are converted into binary numbers
- The output is represented in the form of discrete values.
- Its accuracy is good
- It has large memory space
- It is versatile in nature
- It is suitable for a number of applications
- Its Processing speed is high
- It is highly suitable for business applications.
c) Hybrid Computers: The Hybrid Computers combines the features of both the analog and digital computers. These are used for special analytical applications. Weather-monitoring systems and devices used in Intensive Care Units (ICU) of the hospitals are examples of hybrid computers.
Further more, computers are classified depending on the application as: Special Purpose Computers and General Purpose Computers.
As the name implies the special purpose computers are designed to perform a specific task or a special application.’ The computers used in mining or mineral exploration or those used in ships or aircrafts fall under this category. It does not possess unnecessary options and thus costs less.
The general purpose computers are designed to cater to a wide variety of users or in other words it is capable of meeting the needs of different users. It is capable of storing different programs and performs a variety of operations.
Write about Classification of Computers?
Earlier, Computers are also classified based on the sizes, they are a) Micro Computers, b) Mini Computers, c) Mainframe Computers and d) Super Computers.
a) Micro Computers: Microcomputers, commonly known as PCs. There are very small and cheap. The first microcomputer was designed by IBM in 1981 and was named IBM PC. Later on, many computer hardware companies copied this design and termed their microcomputers as IBM-PC compatible.
Another type of popular PC is designed by Apple. PCs designed by IBM and other PC-compatible computers have a different architecture from that of Apple computers. Moreover, PCs and PC-compatible computers commonly use the Windows Operating system (MacOS). However IBM and IBM compatible PCs are more popular than their Apple counterparts.
- They are small and portable
- They are relatively inexpensive
- They work as soon as they are switched on.
- They do not occupy much space.
- The do not consume much power.
- They are relatively slow.
- Its storage capacity is low.
b) Mini Computers: Mini computer are larger than the micro computers and are more powerful in terms of processing power. Mini computers are mainly multiprocessor systems where many users simultaneously work on the system.
Mini computer possess greater storage capacity and larger memories as compared to microcomputer. These are even capable of handling more input-output device. Their word length is 32 bits. Most minicomputer use Motorola 68030 or 68040 CPU. The processing speed lies in the range 10 to 30 MIPS, memory (RAM) capacity lies in the range 8 MB to 256 MB. The hard disk capacity lies in the range 380 to 3 GB, it can support up to 64 or even hundred terminals. It is used for payroll preparation, accounting and scientific computation. High performance workstations with graphics input/output capability use minicomputer.
- They are small and portable
- They are relatively inexpensive
- They work as soon as they are switched on.
- They do not occupy much space.
- The do not consume much power.
1) They are relatively slow.
c) Mainframe Computers: Mainframe computer are larger, faster and more expensive than other general purpose computers. These are used to handle huge volumes of data. Their word length may be 48 to 64 bit memory capacity, the hard disk capacity 1000 MB to 10 GB or more and processing speed 30 to 100MIPS. These computer even possess and work with more than one processor at the same time. Thus one can see these as multi-user, multiprocessor systems. For mainframe computer highly sophisticated operating systems are needed to control and supervise their operations. They are used where large amount of data are to be processed or very complex calculations are to be made and these tasks are beyond the computing capacity of minicomputer. It is used in research organizations, large industries, large business and government organizations, banks and airline reservation where large database is required. Mainframe computer are IBM 4300 series (small to medium size models), IBM 308X series(large models), the latest model IBM 3090 series (IBM 3090/6000 was first installed in 1988), IBM Enterprise system 9000 series, HP 9000 model 870s/400, HP 9000 model 870s/300, etc.
- They are capable of handling all tasks.
- They require large room space.
- Consumption of electricity is very high.
- Maintenance cost is also very high.
Present days Classification:
Today computers are classified as notebook computers (laptop computers), Personal Digital Assistant (PDA, also known as* palmtop computer), desktop computers (PCs) Workstations, servers, and Super Computers. Laptop or notebook computers are personal portable computers. They are used for word processing and spreadsheet computing while a person is traveling. Their power supply is from batteries. They consume less power. They use hard disks, floppy disks and flat LCD (Liquid Crystal Display) Screen. They can be connected to computer networks.
Desktop Computers: The most common type of personal computer is the desktop computer – a PC that is designed to sit on a desk or table. These are the systems you see all around you, in schools, homes, and offices.
Today’s desktop computers are far more powerful than those of just a few years ago, and are used for an amazing array of tasks.
Workstations: A workstation is a specialized, single-user computer that typically has more powerful than a standard desktop PC. These machines are popular among scientists, engineers, and animators who need a system with greater-than- average speed and the power to perform sophisticated tasks. Workstations often have large, high-resolution monitors and accelerated graphics handling capabilities, making them suitable for advanced architectural or engineering design, modeling, animation and video editing.
Servers: Servers are power computers. A number of PCs and terminals are connected to a server through a communicating network. Server has large disk and RAM capacity. A low-end server contains one microprocessor whereas a high-end server may contain more than one microprocessor. Microprocessor within the computer operate in parallel. A person working on a PC connected to server, makes simple computation on the PC.
d) Super Computers: Super computer is the most powerful of all computers. They have a high processing speed. Their processing speed lies in the range of 400 to 10,000 MIPS, word length 64 to 96 bit, Memory capacity 256 MB, Hard disk capacity 1000 MB and more, and machine cycle time 4 to 6 ns. It is specially designed to maximize the number of FLOPS. Their FLOPS rating is usually more than I gigaflops per second. Supercomputers are mainly used for purposes requiring enormous amounts of data to be processed within a very short time, Whether Forecasting, Space Research, Weapons Research, Atomic Research, Design of Aircrafts etc., are some of the applications. The best known super computers are PARAM series (developed in India) CRAY series, CYBER series and FUJITSU series. .
Super computer can perform billions of instructions per second. Some of the today’s super computer have the computing capability equal to that of 40,000 Micro Computer. A Japanese super-computer has calculated the value of Pi (n) to 16 million decimal places.
- They use several processors working simultaneously.
- They process at a rapid speed.
- They have more main memory.
- They have operations done in parallel, rather than sequentially.
Explain various Computer Generations in detail.
The Computer Generation means step-by-step growth in the technology. Originally, the term generation was used to distinguish between varying hardware technologies. But nowadays, it has been extended to include both the hardware and the software, which together make up an entire computer system.
There are totally five generations of computers till today. Each generation will be discussed in detail. The following table illustrates the Generations of computer hardware:
|S.No||Generation of Computers||Components used||Operating speed|
|1.||First Generation||Vacuum Tubes||Milli Seconds|
|2.||Second Generation||Transisters||Micro Seconds|
|3.||Third Generation||Integrated Circuits (IC) (or) SSI (or) MSI||Nano Seconds|
|4.||Fourth Generation||Micro Processors (or) LSI (or) VLSI||1 to 10 Nano Seconds|
|5.||Fifth Generation||Ultra LSI||1 to 100 Nano Seconds|
a) Ist Generation Computers (1942-1955):- The magnetic relays of the very first computer were replaced by vacuum tubes. The computers which were made of these vacuum tubes came to be known as the first generation computers. The ENIAC computer made use of 18,000 vacuum tubes and relays. It was capable of performing 5,000 additions in one second. It was bulky in size and needed heavy air conditioning.
- Vacuum tubes were the only electronic components available at that time.
- This technology made possible the advent of electronic digital computers.
- These computers were the fastest calculating device of their time.
- These computers could perform computations in milli seconds.
- Very big in Size
- Occupies large space
- High heat production
- High power consumption
- High cost
- NO reliability
- Vulnerable to frequent hardware failure.
- Limited Commercial use
- Need Constant Maintenance.
b) IInd Generation Computers (1955-1964): The transistor was invented in 1948 at the Bell laboratories and was capable of performing all the functions of a vacuum tube at a much faster rate. It consumed little power and generated less heat. The computers which were working with transistors came to be known as the second generation computers. These computers were much smaller, consumed less power and generated little heat and were more reliable. These had capability of performing 20,000 to 50,000 additions per second.
- Small in size
- Better reliability
- Computational time is Micro Seconds
- Less heat generated
- Better Speed
- Better Portability
- Less prone to hardware failure.
- Frequent Maintenance required
- Need Air-conditioning
- Manual Assembly of individual components into a functioning unit was required.
- High Cost
- Commercial production was difficult.
c) IIIrd Generation Computers (1964-1975): The new techniques of Small Scale Integration (SSI) and Medium Scale Integration(MSI) led to the evolution of Integrated Circuit (IC). As many as few hundred transistors can be housed on a single Integrated Circuit. This chip can be as small as 4 to 8 square centimeters in the area and weights few grams. It consumes very little power and its cost is very low. The computers using the Integrated Circuits came to be known as third generation computers. The first computer came from IBM and is called as IBM 360. These computers were small in size and greater in
capacity and performed as many as ten million additions per second.
- Small in size
- More reliability
- Less heat generated
- Computational time is Nano Seconds.
- Less hardware failure.
- Low Maintenance Cost
- Easily portable.
- General purpose computers.
- Less power required
- Commercial production was easier and cheaper.
- Need Air conditioning
- Highly sophisticated Technology required for the manufacture of IC chips.
d) IVth Generation Computers (1975-1989):- The beginning of 1970s saw a totally new face in the computer industry with the introduction of microprocessors. These microprocessors comprised of many LSI (Large Scale Integration) and VLSI (Very Large Scale Integration) circuits having all elements to process the data. These microprocessors have thousands of transistors in them. The computers making use of these microprocessors are known as fourth generation computers.
- These computers were much more small in size.
- Very cheap as compared with previous generation computers.
- Consumed less power
- Mainframes and super computers fall in this generation.
- Having more reliability
- Having less Hardware failures.
- They had large and faster primary and secondary storage.
- These are the general purpose computers.
- Object oriented languages are supported.
- Highly sophisticated Technology required for the manufacture of LSI chips.
e) Vth Generation Computers (1989-Present):- The fifth generation computers have a new technology called Artificial Intelligence incorporated in them. The computers which were made of these Ultra Large Scale Integration (ULSI). came to be known as the fifth generation computers. These computers require new architecture, new memory organizations and new programming languages. These will be the computers that can learn and make decisions.
- The super computers fall under this generation.
- Portable PC’s also fall under this generation.
- These computers consumes less power than the predecessors.
- More user friendly.
- Supports wide operating system environments,
- Supports newer and powerful applications.
- Having much faster and large primary storage capacity.
- The prices range are affordable and very close to human being.
- Supports parallel programming.
Describe about Input / Output Devices
Input and output devices act as an interface between the user and the computer. A device sends information to a computer system for processing is called as an input device and a device that receives and then reproduces or displays the results of that processing is called an output device. Most devices are either input devices or output devices because they can only accept data input from a user and forward the same to the computer system or receive the output data from the computer. There are some devices which are capable of both accepting input and handling output, these types of devices are called I/O devices (input/output devices). Input-output devices are also called as peripherals.
1. Keyboard: Keyboard is the most common and very popular input device which helps to input data to the computer. The layout of the keyboard is like that of traditional typewriter, although there are some additional keys provided for performing additional functions.
2. Mouse: Mouse is the most popular pointing device. It is a very famous cursor-control device having a small palm size box with a round ball at its base, which senses the movement of the mouse and sends corresponding signals to the CPU when, the mouse buttons are pressed.
Generally, it has two buttons called the left and the right button and a wheel is present between the buttons. A mouse can be used to control the position of the cursor on the screen, but it cannot be used to enter text into the computer.
3. Joystick: Joystick is also a pointing device, which is used to move the cursor position on a monitor screen. It is a stick having a spherical ball at its both lower and upper ends. The lower spherical ball moves in a . socket. The joystick can be moved in all four directions. The function of the joystick is similar to that of a mouse. It is mainly used in Computer Aided Designing (CAD) and playing computer games.
4. Light Pen: Light pen is a pointing device similar to a pen. It is used to select a displayed menu item or draw pictures on the monitor screen. It consists of a photocell and an optical system placed in a small tube.
When the tip of a light pen is moved over the monitor screen and the pen button is pressed, its photocell sensing element detects the screen location and sends the corresponding signal to the CPU.
5. Track Ball: Track ball is an input device that is mostly used in notebook or laptop computer, instead of a mouse. This is a ball which is half inserted and by moving fingers on the ball, the pointer can be moved.
Since the whole device is not moved, a track ball requires less space than a mouse. A track ball comes in various shapes like a ball, a button, or a square.
6. Scanner: Scanner is an input device, which works more like a photocopy machine. It is used when some information is available on paper and it is to be transferred to the hard disk of the computer for further manipulation.
Scanner captures images from the source which are then converted into a digital form that can be stored on the disk. These images can be edited before they are printed.
7. Digitizer: Digitizer is an input device which converts analog information into digital form. Digitizer can convert a signal from the television or camera into a series of numbers that could be stored in a computer. They can be used by the computer to create a picture of whatever the camera had been pointed at.
Digitizer is also known as Tablet or Graphics Tablet as it converts graphics and pictorial data into binary inputs. A graphic tablet as digitizer is used for fine works of drawing and image manipulation applications.
8. Microphone: Microphone is an input device to input sound that is then stored in a digital form. The microphone is used for various applications such as adding sound to a multimedia presentation or for mixing music.
9. Optical Character Reader (OCR): OCR is an input device used to read a printed text. OCR scans the text optically, character by character, converts them into a machine readable code, and stores the text on the system memory.
10. Optical Mark Reader (OMR): OMR is a special type of optical scanner used to recognize the type of mark made by pen or pencil. It is used where one out of a few alternatives is to be selected and marked. It is specially used for checking the answer sheets of examinations having multiple choice questions.
A device that can receive data from a computer or another device and create output with that data is called an output device. Examples of various output devices are as:
1. Monitor: A monitor is an output device that is responsible for receiving data from a computer and displaying that information as text or images for users to see.
2. Printer: A printer is an output device that generates, a hard copy of the electronic data stored on a computer or any other device.
3. Projector: Gets data from a computer and displays or projects the same information onto a screen or a wall. A projector cannot directly accept data from a user and send that data to another device.
4. Speakers: Receives sound signal from a computer and then plays that sound signal and thus we hear songs or music or any other audio.
5. Sound Card: The sound card, also known as an audio adapter is the .expansion card or integrated circuit to receive and produce sound. The sound cards operate with the help of a software application and a device driver.
Microphones are the input device that receives the audio signals, and speakers or headphones are the output devices to send audio data.
6. Video Card: A video card is also an expansion card that is attached to the motherboard. It processes the images and video and enhances their display quality.
Most computers have basic video and graphics capabilities, but a video card is required for getting faster and more detailed graphics.
7. Braille Reader: A Braille Reader is an electronic device that allows a blind person to read the text displayed on the monitor screen.
The computer sends a text to the Braille Reader, where it translated into Braille format and displayed by raising rounded pins through a flat surface.
8. GPS (Global Positioning System): Global Positioning System or GPS is a network of satellites to know the exact location of an object on earth. The GPS is composed of a sender and a receiver computer. The GPS comprises 24 satellites, expanded in space about 12000 miles above the earth’s surface.
The GPS and satellite interact using microwave signals to give information regarding location, vehicle speed, etc. GPS is nowadays used in smartphones, vehicles, and many other tracking devices.
Both Input / Output Devices
An input/output device is capable of receiving data from users or another device and also sending data to other devices or computers. That means devices which can be used as both input device and output device are called Input / Output (I/O) devices. Some examples of input/output devices are:
1. USB drive: Also known as a pen drive or flash stick works as both an input device to the computer and as an output device. USB drives receive or save data from a computer as an input and it can also send data to a computer or another device.
2. Modems: It is used to transmit and receive data from one computer to another computer or other devices using telephone lines
3. CD-RW drives and DVD-RW drives: Receives data from a computer as input to copy onto and save into writable CD or DVD. We also use CDs or DVDs to transfer data to a computer.
4. Touch Screen: Touch screen is both an input and output device. By touching the screen input is provided and is a screen, it is used as an output device.