Thursday, June 11, 2015

Types of computer?Classified of computer

What Types of computer?Classified of computer
Types of computer
Computer can be classified through deferment ways. They can be classified on the basis of the way they process data according data, according to their size and model, etc. it is found that many writers have classified computer into Microcomputer, Minicomputer, Workstation, Mainframe & Supercomputer in term of their size but all of these are the types of digital computer so it is better to study them the topic "Type of Digital Computers".
Here we'll classify computer in terms of the way the computer process data. According to the way they process data, computer can be broadly classified into their groups. They are:
1. Digital computer
2. Analog computer
3. Hybrid computer
1. Digital computer
The computer that process discreet data in binary form (i.e. 1&0) is known as digital computer. It required some entity to represent numbers. The representations  is not a simple one-to-one relationship, but is deterred by a kind of algorithm called the  binary number systems, this algorithm transforms a number/ character into a sequence of 0's and 1's internally in the machine (computer).

The accuracy of digital computer I only limited by the size of registers (to be discussed later) and memory. Letters and works are also coded in binary form. Digital computers have almost an unlimited memory and potentially a much higher accuracy, as it doesn't depend on physical quantities for processing.
2. Analog computer
The computer that process continuous date (value/ quantities) is known as analog computer. Computations are carried out with physical quantities such as voltage, current, air pressure, liner distance, temperature; velocities of rotating shift etc. analog computer utilizes some sorts of analogue or analogy, such as Ohm's Law, to affect a solution, and are used most often as controlling device in some continuous process. Since, analog computers use some physical analogue for representing numbers; they can often avoid much time-consuming arithmetic. However, it cannot perform logical operations, it has minimal memory, setting a problem is arduous and even the most sophisticated of them is limited in problem it can accept, furthermore, analog computer can never be extremely accurate, since quantities are always difficult to measure precisely and tend to fluctuate somewhat with change in temperature, humidity, degree of wear, and so on.
3. Hybrid computer
The computer that is especially designed by combining the best features of analog and digital computers is called Hybrid Computer. This computer use both digital and analog Components to process continuous as well discrete (digital data). It can convert data from analog to digital and vice versa with the help of analog to digital converter (ADC) and digital to analog converter (DAC). This computer has speed of analog and accuracy of digital. The use of Hybrid computers has been restricted to the specialized applications like weather forecasting. Hospitals etc. in hospitals, analog part of hybrid computer is responsible for measurement of patient's heartbeat, blood pressure, temperature and other vital signs and them operations is carried out in digital fashion to monitor patient's vital signs.
Different between analog and digital computes
Different between analog and digital computes
Types of digital computers
Digital computers can be classified according to their physical size, speed, processing capacities memory size, disk storage capacities, cost, application areas etc. the various classes of digital computers are explained below:
1. microcomputer
The computer that is based on microchips (microprocessor) such as Intel 8386, 80846 etc is known as microcomputer. It is also known as personal computer or home computer. The word size of microcomputer is 8 to 12 bits. Microcomputer is generally single processor, single user system designed for performing basis operations like education, training, small business applications etc.
It is smaller than microcomputer. IBM PC'S IBM Compatibles, Apple Macintosh etc are its examples.
2. minicomputer
Minicomputer is larger than microcomputer and smaller than mainframe. It is more powerful than microcomputer in terms of processing power and storage capacities. The computer is modified from single user concepts of microcomputer to multi-user concept. The word size is 32 bits or more. It is useful for small business organizations and real-time applications such as processing control system.
IBM 4384, CDC-600, CYBER 170 are its examples.
Furthermore, the new design advancement is computer has evolve and and this advancement in computer is known as Ultra Computer. This advancement will be the new generation of computer.
Characteristics of computers
Irrespective of types and size, all computers have common characteristics. The common characteristics of computer are as follows.
a. speed
Computer can process at extremely fats rate at MIPS (Million Instructions per second). A computer can operate at speed measured in nanoseconds and even in Pico seconds.
The following terms are used to describe the processing capacities.
Millisecond = 10-3 of a second
Microsecond = 10-6 of a second
Nanosecond = 10-9 of a second
Pico second = 10-12 second
b. storage
A computer can store a large amount of data. With more and more auxiliary storages devices, which are capacities of storing huge amount of data. The storage capacity of computer is virtually unlimited. The capacity of secondary memory ranges from 540 MB to multiple of Gigabytes (GB).
c. accuracy
The accuracy of a computer is very high. Errors in computer are often due to human factors rather than the technological flaws. Errors in computer occur if and only if a program is wrongly coded or the data is corrupted or if the program logic is flawed or data is entered wrongly.
d. diligence
Diligence means being constant and earnest in effort and application. Human beings suffer from weakness like tiredness, lacks of concentration etc. humans have feelings, they become sad, depressed, bored and negligent and it will reflect on the work they do. Computer can care all these inabilities of the human begins, as it will not get depressed or losses concentration.
e. versatility
Computers are very versatile machine. They are capable of performing almost any task, provided the task can be reduced to a series of logical steps. They can communication with other computers and can receive and send data in various forms like text, sound, graphics, video etc.
f. automation
The level of automation achieved in a computer is phenomenal. It is not a simple calculator where you have to punch in the number and press the 'equal to ' sign to get the result. One the task is initiated computers can proceed on its own till its completion.
g. reliability
Computer became essential equipment in normal people's day-to day work. The possibility of using the versatile range of devices and durability, its popularity is increasing day by day. Every one performs to use computers as it has more capabilities and it became a reliable machine.
Computer applications(what is Computer Applications)
The computer is truly amazing machine. Today, computers are either directly or indirectly influencing almost every aspect of our lives. Here we'll explain the major application areas of computers.
a. business
In business, computers are used for variety of purposes ranging from decision making to electronic commerce. It is also used to control stock of raw materials and finished product, send bills to customers, calculate employee pay and taxes etc.
b. medicine and health care
Computers are extensively used in medicine. It is used for diagnosing illnesses; monitor the conditions of patients and keeping the necessary records. Many innovative medical application use small, special-purpose computers. For example, pacemakers are computer that operate within the human body help to maintain heartbeat.
At laboratory, computers perform tests such as X-RAY, CT-SCAN etc.
c. education
Computers have brought revolution in the field of education. Now, student, teachers and many others use computers in school and colleges. People use computers in the library to read magazines and journals from the computer terminal rather than searching the shelves for paper originals. Teachers use computer as a presentation tool, to explain difficult topics more clearly and easily to their students use computers to develop their science project, do their mathematical problems.
Student to improve their knowledge of any subject use Computer Assisted Learning (CAL).


Sunday, March 29, 2015

What is the Computers?Introduction of computer

what is Introductions to computers?
Introductions to computers
Key terms
Electronic device
Introductions to computersA device having or using many small parts, such as microchips, that control and d
irect a small electric current. Electronic devices are those, which can operate at low voltage.
Data
It is plural form of 'Datum' meaning fact. It is the representation of facts or observation. Alphabets, numbers and symbols represent data. For example, alphabets (a-z), numbers (0-9) and their combinations, quantity, etc are data.
Information
Data arranged in useful and meaningful from is known as information. In which simple words, we can say that data are raw facts fed as input information is relevant knowledge produced as output of data processing.
Data processing
Data processing is the cycle of input, processing and output.
Volatile
Volatile means "not permanents" it is the process of loosing he (unsaved) data from the memory esp. primary memory when the power is switched off.
Bit
It is the short form of binary digits. It is the smallest unit of memory. It can be either 0 or 1.
Byte
Combination of eight bits is called one byte. One byte represents one character. Character may be A-Z, a-z, numbers or special characters (!, @, #, $, *, <,> etc.)

Unit of memory
1 Bit        = 0 or 1
4 Bits        = 1 nibble
8Bits                = 1Byte
1024 Byte       = 1 kilobyte (KB)
1024 Kilobyte    = 1 Megabyte (MB)
1024 Megabyte = 1 Gigabyte (GB)
1024Gigabyte = 1Terabyte(TB)
1024Terabyte = 1PeraByte(PB)
1024Perabyte = 1EraByte
Units of processing speeds
1 Hz  = one instruction per second
1 KHz = one thousand instructions per second
1MHz = 1000 *1000 instructions per second
1GHz = 1000*1000*1000 instructions per second
Introduction of computer
Computer is a programmable electronic device that can perform mathematical and logical operations at a very high speed.
Generally, computer takes raw data from the user as input and produces the information as output. The principle characteristics of a computer are to respond to a specific set of instructions in a well-defined manner and to execute a pre-seconded list of instruction (a program). Modern computer are electronic and digital. The word "computer" was derived from Latin word "Computer" which means "calculated.
Modern computer generally consists of two basis components. They are:
1. Hardware (what is Computer Hardware?)
The physical components of computer like that wires, transistors, circuit, keyboard, motherboard, Mouse, monitor, power box and etc. which can be touched and felt are known as a hardware device.
General description of different hardware components of a computer systems are explained below:
Front view of system unit
1. Power on/off: this switch is used to switch on (start) or switch off (shut dow
Front view of system unit
n) the computer systems.
2. Reset button: this button is used to restart the computer without disconnecting the power supply. It is very useful when computer hangs.
3. Turbo button: it is generally found in older types of CPU assign. Pressing this button increases the processing speed of the computer.
4. Floppy disk drive: this drive is for inserting a 3.5" floppy disk for transferring data from/to the computer. Every disk requires a drive for its operation.
5. CD-ROM Drive: this drive is for inserting a CD for listening to music (Audio CD) or for viewing movies (Video CD) and program CD to install new programs.

6. Lights: the front side of computer system consists lights for power, turbo, hard disk, floppy disk, CD-ROM etc. the variety of colored lights (red or green) indicates that the computer is busy in processing.
Back view of the systems unit
In the back view of the computer system, there are different types of ports. The ports are connected to the particular device through the cables. So the connector of the cables should be matching with respective ports.
Back view of the systems unit
1. Power in and out socket: the cable plugged into the power in socket brings power from external sources to the system unit and the cable plugged to the power out carries power from system units to the monitor.
2. Serial ports: these ports connects computer to a mouse or modem. Most of the computers found today have two serial ports.
3. Video/monitor port: the cable from the monitor fits into port and carries the information to be displayed on the monitor.
4. Parallel port: it is generally used for connecting computer to the printer.
5. Keyboard port: it is circular in shape. The keyboard cable fits into the keyboard port.
6. USB Port: USB stands for universal serial bus. USB port is very useful for connecting new generation devices such as video camera, Keyboard, Mouse new generation devices such as video camera, pen drive etc.
7. Nic port: Nic stand for network interface card. Nic port provides connection between computer through wires.
8. Fan Housing: the fan placed at the back of the system unit helps to remove the hot air so that systems unit is safe from overheating.
Software (what is software?)
Software is the part of computer, which is responsible for the processing of data. The logical components or set of procedures or routine of instruction are called software. Without software a commuter is just wireless metallic box.
All general process computers require the following hardware components:
1. Input unit: this unit of computer is responsible to feed the data and instructions into the computer. Some common input devices are keyboard, muse, scanner, pen drive port, joystick, etc.
2. Memory Unit: this unit of computer is responsible to store data and programs permanently or temporarily into the computer. The memory can be both interest and external, depending upon its location. The internal memory is generally known as primary or main memory. It is directly accessible to CPU (central processing Unit) and is volatile in nature. The external memory is generally known as secondary memory and is not directly accessible to CPU. It is accessed via I/O controllers. It is non-volatile in nature. It included magnetic disk; magnetic drums etc. whereas primary memory included ROM & RAW.
3. Central processing Unit (CPU): CPU is the heart of computer, which executes instruction stored in the main memory. It performs arithmetic and logical operations in addition to control ad supervision of the entire computer system. The main components of CPU are control Unit. ALU (Arithmetic & Logical Unit), and Resisters.
4. Output unit: the port of computer, which is responsible to display and produce the information processed by the CPU, is known as output unit. Some common output devices are monitor, printer, speakers, etc.
Notes: this is hardware components-input units; output unit, memory unit and CPU are discussed in detail in coming units.







Tuesday, December 9, 2014

What is computer ?

What is computer meaning/ definition

The computer means/meaning: the computer is a electronics device which is capable of receiving information (means data received) in a particular for and of performing a sequence of systems operations in accordance with a predetermined but variable data faltering a set of processing instruction (systems program) to produce a result in the form of information result signal issue for devices.