Syllabus:
- General Computer topics: Introduction to computers, information technology.
- Generations of computers, mainframe, mini, micro, super computers and its applications.
- Components of computers: Input devices , Output devices Computer hardware, computer software
- General block diagram of computer, processor, memory.
- Application programming software’s MS-Word, MS-Excel etc.,
6. Operating system, different types of operating systems and its advantages.
Introduction to computers
What isinformation technology?
Using technology for data processing and do arithmetic and logical operations is known as information technology.
What is a computer?
An electronic device that performs storage and processing of data, have set of input and output devices connected to it.
Types of computers:
According to the purpose there are two types of computers:
1. General purpose computers
general-purpose computer
Refers to computers that follow instructions, thus virtually all computers from micro to mainframe are general purpose. Even computers in toys, games and single-function devices follow instructions in their built-in program. In contrast, computational devices can be designed from scratch for special purposes (seeASIC).
2. Special purpose computers
A digital computer designed to solve a narrow range of problems. Special-purpose computers are simpler and cheaper than general-purpose computers but have more limited logical and computational capabilities.
In special-purpose computers, the logical structure, instruction repertory, and data input-output devices are adapted to solve strictly defined problems as efficiently as possible. The instruction repertory is most often of the one-address type and involves a limited number of operations. Numbers are usually represented in fixed-point form; the number of binary digits used is comparatively small: up to 20–25. Special-purpose computers are generally designed to solve problems repeatedly in accordance with previously prepared programs while periodic or continuous changes occur in the input data. In order to ensure high computer speed and reliability, the programs are stored in nonvolatile memory units.
Special-purpose computers are often equipped with analogue-to-digital converters, state locks, timers, switches for signals from external sources, display units, lighted panel indicators, and plotters. The design of a particular special-purpose computer depends on the conditions in which the computer is to be used. For example, computers on board spacecraft and aircraft should combine high efficiency and reliability with small size and weight. Such computers should consume a minimum of energy and be capable of operating under sharply variable climatic and mechanical conditions.
The principal area of application of special-purpose computers is automatic control systems. Special-purpose computers can be effectively used in combination with general-purpose computers—for example, to solve special problems in the preparation and processing of information and to solve problems in the simulation of various processes.
According to work there are two types of computers:
1. Digital computers
2. Analog computers
Generations of computers
Mainframe computers
Were appeared in 1950’s.
Capacity: had low size of memory.
Speed: small speed
Size: Large in size because they were using vacuum tubes.
And these types developed and became
Capacity: high, speed: more and more,
Cost: very expensive
Used In very large companies.
Mini computers
These were in 1960
Capacity : Larger than first generation of mainframe computers.
Size :smaller than first generation mainframe computers using silicon slides.
Memory : the size of memory is larger than the mainframe computers.
Speed : higher speed than first mainframe computers.
Micro computers:
These were present in 1980’s.
Capacity, memory ,speed are higher than the mainframe and mini computers.
Size of micro computer is smaller than the mainframe and mini computers.
Micro computers are of two types.
1.Desktop computers
2.laptops
Generally computers have two parts:
1. Hardware: physical parts of the computer system and
2. Software: programs or instructions that tell the computer hardware how to transfer input data into necessary output.
Input /output devices
Input devices: allow you to input information to the computer.
- Keyboard
- Mouse
- Scanner
- Webcam
- Joystick
- Touch screen
- Digital camera.
- Microphone
- Light pens
Output devices:
Allows you to view the data or information in different forms.
Like information on screen ,print out or like images etc.
- Screen or monitor
- Flat screen monitors
- Printers
Different types of printers are:
Laser printers:A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper.
Inkjet printers:An inkjet printer is a type of computer printer that creates a digital image by placing variable-sized droplets of ink onto paper.
Dot matrix printers: A dot matrix printer or impact matrix printer is a type of computer printer with a print head that runs back and forth, or in an up and down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like the print mechanism on a typewriter.
Thermal printers:A thermal printer (or direct thermal printer) produces a printed image by selectively heating coated thermo chromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head.
Plotters: A plotter is a computer printing device for printing vector graphics.
In the past, plotters were widely used in applications such as computer-aided design.
General block diagram of computer
General block diagram of computer consists of the following peripherals.
Processor: Micro processor acts as human brain in computer system. Its size is only 5* 5cm in width and height but capable of doing all the arithmetic and logic problems very quickly.
Also called as the central processing unit and it has two parts namely:
1.ALU(Arithmetic Logic Unit):performs calculations such as additions, subtractions, multiplications etc and logical problems like Boolean values, true or false etc.
2.CU(control unit):control unit controls the flow of data from processor to storage devices and storage devices to processor.
The speed of processor is measured in MegaHertzMHz)
Memory: Internal storage areas in the computer. The term memory identifies data storage that comes in the form of chips, and the word storage is used for memory that exists on tapes or disks.
RAM: Random Access Memory, can read and write data.
for random access memory, a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.
RAM is volatile, meaning that they lose their contents when the power is turned off.
ROM: In contrast, ROM (read-only memory) refers to special memory used to store programs that boot the computer and perform diagnostics.
Cont add or remove data.
The size of memory is measured in bytes or mega bytes.
We can increase the size of memory by adding the extra chips of memory in mother board.
1 byte = 8 bits
1 Kilo byte= 1024 bits
1 mega bytes= 1024 kilo bytes
1giga byte = 1024 mega bytes.
Storage devices: A device capable of storingdata. The term usually refers to mass storage devices, such as disk and tape drives
Different storage devices are:
Floppy disks, hard disks, zip disks, CD’s, flash memory etc.
Ports and slots:
- Serial port can send and receive one bit at a time.
- Parallel port send and receive bits in group.
- Keyboard, mouse, video and micro phone, audio ports are there for all other devices working for the system.
Transformer:
Transfers the suitable power supply for the system, and built in the CPU.
Mother board:In personal computers, a motherboard is the central printed circuit board (PCB) in many modern computers and holds many of the crucial components of the system, while providing connectors for other peripherals.
Contains :
Mother board contains place for RAM, chips, processor, expansion cards, battery etc.
How we can control the performance of the computer?
Ans: speed of the processor must high, i.e., the number of operations per second must be high, size of memory must be large, and size of the hard disk must be high.
Software
Software: Programs or the instruction that tells the computer hardware, how to transfer the input data into necessary output.
There are two types of software’s :
- Operating system software’s
- Application programming software.
Operating system software:
Number of programs that controls and organize the computer works.
An operating system (OS) is software, consisting of programs and data, that runs on computers and manages computer hardware resource and provides common services for efficient execution of various application software.
Disk Operating System:An Operating System is a set of programs that help in controlling and managing the Hardware and the Software resources of a computer system.
Microsoft Windows:
Microsoft windows comes in different version starting from
Window’s 95, 98, 2000, xp, vista, widows7.
It has following features that:
- Icons that represents the applications.
- Documents (different files.)
- Folders (collection of files.)
Microsoft windows have the following advantages:
- Easier for people to understand and learn than typed commands.
- There are some commands like undo redo copy paste
- etc that easy handling of data.
- Easy to use mouse and keyboard for most commands.
UNIX (Multiple user operating systems):
Operating system is widely used for multiuser systems as servers, mainframes, super computers.
UNIX operating system provides most commands for internet services.
Application software Programs:Application software, also known as an application or an "app", is computer software designed to help the user to perform singular or multiple related specific tasks.
Application software is a complete and self contained program that perform an useful task.
Most popular application programs are Microsoft office, Microsoft paint etc.
Microsoft office contains the following packages like
MS-word— facilitates to create documents, letters, lectures etc.
MS-access— The Application software to create data base for keeping data in tables. Provides information to the user requirements.
MS-PowerPoint— the application software to create presentations for business, academic and informative areas. Provides great features of graphical presentations.
MS-excel— this application software is to create excel worksheet to manage financial and statistical information. provides with various mathematical and statistical calculation very easily.
MS-outlook—this application software is used creates email groups to communicate multiple user and send and receive any sort of information thorough outlook emails.
MS-publisher—
Microsoft Office Publisher is the business publishing program that helps you create, design, and publish professional-looking marketing and communication materials. You can create materials for print, e-mail, and the Web with an intuitive, task-based environment that guides you from initial concept to final delivery in-house without professional design and production expertise.
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