The word 'data' refers to, facts concerning things such as people, objects, events etc. A list of class students, showing students roll numbers, names, marks etc. is an example of student's data. Therefore, data is defined as; collection of raw facts and figures, which is collected for specific purpose. The data may be in the form of text, numbers, sounds, images, video clips etc.
Types of Data
Data may be of different forms that can be processed through computer. These are number, text, images, audio, and video.
1. Numeric
Numeric data consists of digits from 0 to 9, + (positive) or - (negative) signs and decimal points. It can be of integer type or real type data.
- Integer data: It consists of positive or negative whole values including 0. For example, 420, 302, +62, -26 etc.
- Real data: It consists of values that have decimal point. For example, 15.4, .006,4.07, -6.27 etc.
The numeric data is represented by using bit patterns. A number is directly converted to a binary number.
2. Text
A text consists of words,: sentences, paragraphs etc. For example, ‘USA’, “I Live in USA”, and this paragraph written about “Text” etc. The text is stored as ASCII codes. In data processing, text is also represented as a sequence of bits or bit patterns. Different coding schemes have been designed to represent different letters or symbol. The process of representing symbols in binary form is called coding.
3. Image
Image data consists of charts, graphs, pictures and freehand drawings. Image data is also represented by bit patterns, but to represent image data, different mechanism is used. The simplest method to represent image, is to divide the image into matrix of pixels (picture element). A pixel represents a smallest dot of the image. The size of the pixel depends on the resolution of the image. For example, if the image of size 2 x 3” has 5,000 pixels, while another image of the same size has 10,000 pixels. In the second case, the resolution is higher, but more memory is needed to store the images.It must be noted that each pixel is assigned a bit pattern. For black and white image, 1-bit is required to represent a single pixel. In case of color, each colored pixel is decomposed into three primary colors such as red, green, and blue (RGB). The intensity of each color is also measured.
It must be noted that each pixel is assigned a bit pattern. For black and white image, 1-bit is required to represent a single pixel. In case of color, each colored pixel is decomposed into three primary colors such as red, green, and blue (RGB). The intensity of each color is also measured.
Each colored pixel has three bit patterns. These are:
- One to represent intensity of red color.
- One to represent intensity of green color.
- One to represent intensity of blue color.
4. Audio
Audio is a representation of sound. It is continuous and not discrete. The audio data is in the form of continuous signal. It is converted to digital form before to enter into the computer.
5. Video
Video consists of full-motion images that create actions and movements. It can be produced by a video camera.
Categories or Levels of Data Processing
Data is processed to get the required results. Different operations may be performed on data. Therefore, data processing is defined as:
"A sequence of operations on data to convert it into useful information is called data processing". The important operations that can be performed on data are:
- Arithmetic and logical operations on data to get required results.
- To send and receive data from one location to another.
- Classification of data.
- Arranging data into a specific order etc.
The data processing is divided into three categories or levels.
1. Manual Data Processing
In manual data processing, data is processed manually without using any machine or tool to get required result. In manual data processing, all the calculations and logical operations are manually performed on the data. Similarly, data is manually transferred from one place to another. This method of data processing is very slow and errors may occur in the output.
In Pakistan, data is still processed manually in many small business firms as well as government offices & institutions.
2. Mechanical Data Processing
In mechanical data processing, data is processed by using different tools like calculators or other mechanical devices. This method of data processing is faster and more accurate than manual data processing.
3. Electronic Data Processing
It is the modern technique to process data. The data is processed through computer. Data and set of instructions are given to the computer as input and the computer automatically processes the data according to the given set of instructions.
The computer is also known as electronic data processing machine. This method of processing data is very fast and accurate. Now-a-days, the data is processed and analyzed through computers. For example, the results of students are prepared through computer; in banks accounts of customers are processed through computers etc.
Data Processing Cycle
The data processing is very important activity and involves very careful planning. Usually, data processing activity involves three basic activities.
1. Input
2. Processing
3. Output
1. Input
It is the process through which collected data is transformed into a form that computer can understand. It is very important step because correct output result totally depends on the input data. In input step, following activities can be performed.
i) Verification
The collected data is verified to determine whether it is correct as required. For example, the collected data of all B.Sc. students that appeared in final examination of the university is verified. If errors occur in collected data, data is corrected or it is collected again.
ii) Coding
The verified data is coded or converted into machine readable form so that it can be processed through computer.
iii) Storing
The data is stored on the secondary storage into a file. The stored data on the storage media will be given to the program as input for processing.
2. Processing
After completing the processing step, output is generated. The main purpose of data processing is to get the required result. Mostly, the output is stored on the storage media for later use. In output step, following activities can be performed in a systematic manner. Some of the important activities are:
i) Classification
The data is classified into different groups and subgroups, so that each group or sub-group of data can be handled separately.
ii) Storing
The data is arranged into an order so that it can be accessed very quickly as and when required.
iii) Calculations
The arithmetic operations are performed on the numeric data to get the required results. For example, total marks of each student are calculated.
iv) Summarizing
The data is processed to represent it in a summarized form. ft means that the summary of data is prepared for top management. For example, the summary of the data of student is prepared to show the percentage of pass and fail student examination etc.
3. Output
After completing the processing step, output is generated. The main purpose of data processing is to get the required result. Mostly, the output is stored on the storage media for later user. In output step, following activities can be performed.
i) Retrieval
Output stored on the storage media can be retrieved at any time. For example, result of students is prepared and stored on the disk. This result can be retrieved when required for different purposes.
ii) Conversion
The generated output can be converted into different forms. For example, it can be represented into graphical form.
iii) Communication
The generated output is sent to different places. For example, weather forecast is prepared and. sent to different agencies and newspapers etc. where it is required.
iv) Feedback
After generated output and performing all activities on the output, feedback about the generated output is collected. It is very important activity It is used to improve performance of the data processing system, so that better output can be generated in future.
The output phase also involves activity through which output result is tested. If the output result is accurate, the data processing cycle is completed. If output result is not accurate, some of the above-mentioned steps (or all steps) are repeated again and again until the accurate result is achieved.
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