NOTESNOTES

INTRODUCTION TO COMPUTERINTRODUCTION TO COMPUTER103103

BASIC OPERATIONBASIC OPERATION Some basic operation for converting data into useful

information are as follows:1. Inputting: 1. Inputting: Process of entering data and instructions in to

computer system.2. Storing: 2. Storing: Saving data & instructions to make them readily

available for initial or additional processing as & when required.

3. Processing: 3. Processing: Performing arithmetic operations, or logical operations on data to convert them into useful information.

4. Outputting: 4. Outputting: Process of producing useful information or results for a user.

5. Controlling: 5. Controlling: Directing the manner & sequence in which the above operations are performed.

MEMORYMEMORY In computing, memory refers to the physical devices used to

store programs or data on a temporary or permanent basis for use in a computer or other digital electronic device. The term primary memory is used for the information in physical systems which function at high-speed (i.e. RAM).

There are two main types of memory: volatile and non-volatile. Examples of non-volatile memory are flash memory and ROM/PROM/EPROM/ EEPROM memory. Examples of volatile memory are primary memory (RAM), and fast CPU cache memory.

Volatile memory is computer memory that requires power to maintain the stored information. Non-volatile memory: Non-Volatile memory is computer memory that can retain the stored information even when not powered.

PRIMARY/MAIN MEMORY:- PRIMARY/MAIN MEMORY:- RAM is known as Random Access Memory and also known as internal or main memory. It is a read and write memory of a computer. The user can write information into RAM and read information from it. It is called Random Access Memory because any of the locations on a chip can be randomly selected and used to directly store and retrieve data and instructions stored in it is vanished as soon as power is turned off.

SECONDARY STORAGE UNITSECONDARY STORAGE UNIT• ROM- ROM- ROM is read only memory. This is non-volatile memory. Its contents are

retained even if the power supply goes off. ROM is used for permanent storage of information. The stored information can only be read from ROM at the time of operation. Data stored in a ROM can only be read and used- they cannot be changed. This is the reason why it is called Read only Memory.

• PROM-PROM- This is Programmable Read Only Memory. User can program it according to their needs. The disadvantages of PROM is that it can be programmed only once. Thus the user cannot change its contents after it is programmed once.

• EPROM- EPROM- This is Erasable Programmable Read only memory. EPROM overcomes the problem of ROM and PROM. It is possible to erase information stored in an EPROM and the EPROM can be reprogrammed to store new information. But there are some limitations- (i) The EPROM chip is removed from the computer's board to erase its contents. (ii) The computer data is erased in this process. User can not erase only some particular data stored in EPROM.

• EEPROM- EEPROM- This is Electronically Erasable Program Read only memory. It can be both programmed and erased. The disadvantage of EPROM are removed in it. The chip need not to be removed from the computer for erasing. It is also known as Flash Memory.

CACHE MEMORYCACHE MEMORY Cache (pronounced cash) memory is extremely fast memory that is

built into a computer's Central Processing Unit, or located next to it on a separate chip. The cache memory is placed in between the main memory and the CPU. It is much faster than main memory. The cache memory is not accessible to users. It is used to speed up the execution. It is used to temporarily store very active data and instruction s during processing. Cache memory is random access memory. As the microprocessor processes data, it looks first in the Cache memory and if it finds the data there, it does not have to do the more time-consuming reading of data from larger memory.

The CPU uses cache memory to store instructions that are repeatedly required to run programs, improving overall system speed. The advantage of cache memory is that the CPU does not have to use the motherboard's system bus for data transfer. Whenever data must be passed through the system bus, the data transfer speed slows to the motherboard's capability. The CPU can process data much faster with the help of cache memory.

SECONDARY STORAGE SECONDARY STORAGE DEVICESDEVICES

Secondary Storage devices those are used for storing the data in a permanent manner means all the data will remain stored whether the power is switched on or switched off means the power will never effect on the system. For storing the data in a permanent manner we uses the Secondary Storage Devices.

SOME SECONDARY STORAGE SOME SECONDARY STORAGE DEVICESDEVICES

• Magnetic Tapes: Magnetic Tapes: The Magnetic Tapes is the type of Secondary Storage Device. The Magnetic Tapes are used accessing the data into the sequential form and the tape also contains a ribbon which is coated on the single side of the tape. They can store huge amount of data into the tape drive. But the main limitation of the tape drive is that we cant access the data from the disks directly means if we wants to 100th record from the tape then we must have to move all the previous i.e. 99th records first. And the tapes are also easily damaged due to the human errors.

• Floppy Diskette: Floppy Diskette: The Floppy Disk is also a Secondary Storage device which is used for storing the data in a permanent manner. The Floppy Disk also stores all the data into the form of tracks and sectors and the floppy disk provides both reading and writing the data into the disk. The Floppy Disk is also called as reusable disk means the Floppy Disk provides us the facility to read and writes the data into disk as and when necessary and also many times. We can read and write the data from the disk. The main advantage of the Floppy Disk is that the data can be stored many times but the main limitation of the floppy disk is that floppy disk have a small capacity and the Floppy Disk also doesn't have reliability means the data stored into the disk may not be used for long time because the floppy disk is very sensitive thing when we move the head of the disk again and again then the floppy disk gets damaged. So that we can say that Floppy Disk is not a reliable thing.

• Optical Disks: Optical Disks: The Optical Disks are also called as the CD-ROM's means Compact Disk Read Only Memory which is also used for storing the data into the disk. CD-ROM contains the data which is truly readable means we cant edit the contents of the CD-ROM means once data has been written into the CD, we can be able to change the contents of the disk and the data which is stored on the disk can be any time read by the user. The CD-ROM provides us the large capacity in compare to the Floppy Disks.

• HardDisk: HardDisk: A hard disk is part of a unit, often called a "disk drive," "hard drive," or "hard disk drive," that stores and provides relatively quick access to large amounts of data. Today's computers typically come with a hard disk that contains several billion bytes (gigabytes) of storage. A hard disk drive is a data storage device used for storing and retrieving information from non-volatile memory(retaining its data even when powered off) in a random access manner (data can be retrieved in any order rather than just sequentially).

DIFERENCE BETWEEN DATA & INFORMATION-DIFERENCE BETWEEN DATA & INFORMATION-Data is raw material for data processing. data relates to fact, event and transactions. Data refers to unprocessed

information. Information is data that has been processed in such a way as to be meaningful to the person who receives it. it is any thing that is communicated. The words Data and Information may look similar and many people use these words very frequently, But both have lots of differences between them.

DATA-DATA-• The word 'Data' is derived from the plural form of latin word 'Datum', which means 'to give'.• Data is a collection of raw facts.• May or may not be meaningful.• Input to any system may be treated as Data.• Understanding is difficult.• Data must be processed to understand.• Data may not be in the order.• Example: Statistics, numbers, characters, images.INFORMATION-INFORMATION-• The word 'Information' is derived from latin word 'Informare', which means 'to instruct'.• Information is the outcome derived after processing the data.• Information is always meaningful.• Output after processing the system is Information.• Understanding is easy.• Information is already in understandable form, it may be processed further to make it more understandable.• Information should be in the order.• Example Reports, Knowledge.

DATA PROCESSING SYSTEMSDATA PROCESSING SYSTEMS Data processing is any process that a computer program does

to enter data and summarize, analyses or otherwise convert data into usable information. It involves recording, analyzing, sorting, summarizing, calculating, and storing data. Because data are most useful when well-presented and actually informative, data-processing systems are often referred to as information systems.

ELEMENTS OF DATA PROCESSINGELEMENTS OF DATA PROCESSING In order to be processed by a computer, data needs first be converted into a machine

readable format. Once data are in digital format, various procedures can be applied on the data to get useful information. Data processing may involve various processes, including:

• DATA SUMMARIZATION: DATA SUMMARIZATION: Since the data in the data warehouse is of very high volume, there needs to be a mechanism in order to get only the relevant and meaningful information in a less messy format. Data summarization provides the capacity to give data consumers generalize view of disparate bulks of data.

• DATA AGGREGATION: DATA AGGREGATION: Data aggregation is any process in which information is gathered and expressed in a summary form, for purposes such as statistical analysis. A common aggregation purpose is to get more information about particular groups based on specific variables such as age, profession, or income. For example, a site that sells music CDs might advertise certain CDs based on the age of the user and the data aggregate for their age group.

• DATA VALIDATION: DATA VALIDATION: In computer science, data validation is the process of ensuring that a program operates on clean, correct and useful data. It uses routines, often called "validation rules" or "check routines", that check for correctness, meaningfulness, and security of data that are input to the system.

• DATA TABULATION: DATA TABULATION: The process of placing classified data into tabular form is known as tabulation. A table is a symmetric arrangement of statistical data in rows and columns. Rows are horizontal arrangements whereas columns are vertical arrangements.

• STATISTICAL ANALYSIS: STATISTICAL ANALYSIS: Statistics is the study of the collection, organization, analysis, and presentation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments.

DATA TYPEDATA TYPE In computer science and computer programming, a data type or simply

type is a classification identifying one of various types of data, that determines the possible values for that type; the operations that can be done on values of that type; the meaning of the data; and the way values of that type can be stored. Data types are used within type systems, which offer various ways of defining, implementing and using them. Basically, there are three types of data type- alphanumeric, alphabetic and numeric data type. In alphanumeric data type, alphabets, numeric values and special symbols includes. In alphabets data type, character values includes and In numeric data type, numeric values like integers, float, real numbers includes. Common data types may include:

• Integers• Booleans• Characters• Floating point numbers• Alphanumeric strings

AUDIO & VIDEO AND THEIR PRESENTATION-AUDIO & VIDEO AND THEIR PRESENTATION-In computers, audio is the sound system that comes with or can be added to a

computer. Video refers to recording, manipulating, and

displaying moving images, especially in a format that can be presented on a television. It refers to displaying images and text on a computer monitor.

A video and audio presentation is a great way to capture the attention of an

audience, whether in a business meeting or in a classroom. When audio and video are combined in a presentation, the end result is very much like a movie. If user need to create their own video and audio presentation for an audience, they can do so using any standard video-editing software, such as Windows Movie Maker.

GRAPHIC & IT'S PRESENTATION-GRAPHIC & IT'S PRESENTATION-Refers to any computer device or program that makes a computer capable of displaying and manipulating pictures. The term also refers to the images themselves. For example, laser printers and plotters are graphics devices because they permit the computer to output pictures.

A type of business software that enables users to create highly stylized images for slide shows and reports. The software includes functions for creating various types of charts and graphs and for inserting text in a variety of fonts. Presentation graphics is often called business graphics.

DISK OPERATING SYSTEM(DOS)-DISK OPERATING SYSTEM(DOS)-DOS (Disk Operating System) was the first widely-installed operating system for personal computers. DOS was/is a non-graphical line-oriented command- or menu-driven operating system, with a relatively simple interface but not overly "friendly" user interface. The term DOS can refer to any operating system, but it is most often used as a shorthand for MS-DOS (Microsoft Disk Operating System). Originally developed by Microsoft.

TEN COMMANDS OF DOS-TEN COMMANDS OF DOS-• To display Directories-

Syntax- C:\> DIRSyntax- C:\> DIRo To display directories in page wise-

Syntax- C:\> DIR/pSyntax- C:\> DIR/po To display directories in width wise-

Syntax- C:\> DIR/wSyntax- C:\> DIR/wo To display directories as well as sub directories-

Syntax- C:\> DIR/sSyntax- C:\> DIR/s• To make directory-

Syntax- C:\> MKDIR [DIRECTORY NAME]Syntax- C:\> MKDIR [DIRECTORY NAME]• To remove directory-

Syntax- C:\> RMDIR [DIRECTORY NAME]Syntax- C:\> RMDIR [DIRECTORY NAME]• To make file-

Syntax- C:\> COPY CON [FILE NAME]Syntax- C:\> COPY CON [FILE NAME]{{

FILE CONTENTSFILE CONTENTS}}Ctrl+zCtrl+z

• To view file-Syntax- C:\> TYPE [FILE NAME]Syntax- C:\> TYPE [FILE NAME]

• To edit file-Syntax- C:\> EDIT [FILE NAME]Syntax- C:\> EDIT [FILE NAME]

• To copy a file from one drive to another drive-Syntax- C:\> COPY [PATH1] [PATH2]Syntax- C:\> COPY [PATH1] [PATH2]

• To open a control panel-Syntax- C:\> CONTROLSyntax- C:\> CONTROL

• To delete a file-Syntax- C:\> DEL [FILE NAME]Syntax- C:\> DEL [FILE NAME]

• To change the current drive-Syntax- C:\> [DRIVE NAME]Syntax- C:\> [DRIVE NAME]