Lecture 1 :introduction to computer
- 1. Lecture:Barkhad mohamed omar{suldaan} Book:-Introduction to Computer. Faculty: BA & public administration Lecture hours:2hrs
- 2. Concept of Computers Introduction. Computer is electronic equipment, it is mainly used for automating manual tasks. Using computer you can perform tasks quickly, effectively and in error free manner. Be it any organization, office , factory or institution, you can find people making use of computer there. In offices, computers are used for preparing letters. Documents and reports. The first mechanical computer, created by Charles Babbage in 1822, doesn't really resemble what most would consider a computer today.
- 3. What is computer? Computer is an electronic device used to process data, converting the data into meaningful information that is useful to people. Computer is an electronic device allows inputting data process output and storage device.
- 4. Block diagram of computer. As you know computer is an electronic device it comprises of many units these units work in coordination with each other to perform the given task. Block diagram of computer is show figure 1.1 Rifer this figure and note that computer comprises of following units 1.Input unit. 2.Output unit. 3.input/output unit. 4.Central processing unit{CPU} a)Memory unit b)Arithmetic and logic unit{ALU} c)Control unit.
- 5. How many parts of computer Input unit System unit Output unit 1. Keyboard 2. Mouse 3. Microphone 4. Scanner 1. Processor 2. Motherboard 3. Ram & Rom 1. Monitor 2. Printer 3. speaker
- 6. Input units 1.keyboard:-keyboard consist of many keys.keys have alphabets, numbers, characters or words written on them . Keys Keys of the keyboard are broadly classified into following categories: A)Alphabet keys=A-Z B)Number keys=1-0 C)Special character keys=@${} D)Function keys=f1-f12 E)Cursor keys= F)Action keys= shift, del, ctrl, alt, insert, etc
- 7. 2.mouse:- is an input device it is shown 1.4 figure. It looks like a real mouse with few buttons placed on its back . when mouse is connected to the computer an arrow sign appears on the monitor screen. this sign is called mouse pointer.
- 8. 3.CD-Rom:-CDis acronym for(compact disk)it works as a medium for storing data or instructions it looks like circular plastic disk CD-ROM drive is an input unit that reads data from CD, as the name indicates, CD-ROM (compact disk read only memory)can only read data from CD, it can’t write on it . CD and CD-ROM drive are shown in figure 1.5 Part’s of CD. There are two part’s of the CD. A)CD-R=compact disk read. B)CD-RW=Compact disk Re-writeable. What Is the Difference between CD and DVD? CD, short for Compact Disc, is an optical medium that can store digital data. Usually, a standard CD can store about 700MB of data. Digital Versatile Disc, is also an optical medium to store digital data. A standard DVD can hold 4.7 GB of data. So DVD is widely used to store large files like video and movies. The capacity is the biggest difference between CD and DVD.
- 9. 4.light pen:-looks like an ordinary pen and performs same function in computer world, which an ordinary pen does in physical world you hold the pen and write on a special pad or directly on the screen. 5.Touch screen:-are special screen ,which are touch sensitive ,when you touch a part of the screen they are able generate information that the screen has been touched and that too, on particular location
- 10. 6.Joystrick:-consists of a lever placed vertically in the middle of small board, the lever can be moved in any desired direction, joystick also contains few buttons. When joystick is connected to the computer, many game applications take input through joystick .when you move the lever of the joystick, objects in the game(like ship , bird, car etc)also move. 7.Bar code reader:-is basically an input device it is used for reading bar codes that appear on the wrappers of the objects like toothpasters, soaps, biscuits back over of the books etc. When bar code reader is move over the bar the bar code , pressing a button ,it emits light (laser beam)
- 11. 8.Scanner:- is a device that scans pictures , maps photos, documents etc. 9.OCR:-optical character reader it can be converted into document file , which could either be edited through a text editor(like notepad wordpad etc) or word processing software like ms word, word perfect etc.
- 12. 10.MICR:-magnetic ink character reader is an input device which reads special characters , written using magnetic ink best example of magnetic ink characters is the cheque numbers that are written on modern cheques. 11.OMR:-optical mark readers are special type of input devices that read a document on which an optical mark has been pet to understand the usage and concept .
- 13. 12.Microphone:-is an input device using which speech input is provided to the computer. These days , microphones are being widely used for internet telephony , video conferencing voice mail , voice chat etc. “sound recorder” application of windows provides facility for recording the sound in computer and introducing few special effects in it.
- 14. 13.Web camera:-is an input device which captures live movements and provides them as input to the computer. 14.Digita camera:-is a device which captures high-resolution images and stores them in its memory , in digital form .