Data is defined as any collection of facts. Thus, sales reports, inventory figures, test scores, customers’ names and addresses, and weather reports are all examples of data. Note that data may be numerical (e.g, inventory figures and test scores) or they may be numerical (e.g. , names of students and addresses, drawings).
Data processing is the manipulation of data into a more useful form. It is the modern name for paperwork and involves the collecting, processing, and distributing of facts and figures to achieve a desired result. Data processing includes not only numerical calculations but also operations such as the classification of data and the transmission of data from one place to another. In general, we assume that these operations are performed by some type of machine or computer, although some of them could also be carried out manually. Data processing system refers to the equipment or devices and procedures by which the result is achieved.
Modern data processing employing machines and other devices falls into two basic categories, mechanical data processing and electronic data processing. In some data processing operations, all works is still done using manual procedures. These system employs tools and materials such as pencils, pens, multiple-copy forms, carbon paper and filling cabinets. Mechanical processing system use a combination of manual procedures and mechanical equipment. The system uses various devices such as typewriters, sorters, calculators, collators, tabulators, duplicators, and verifiers. Most of these system operate on punched cards. In electronic data processing different types of input, output, and storage devices may be interconnected to an electronic computer to process data. A major difference between the two categories is that the mechanical systems usually require constant manual intervention between the different data processing operations, whereas in an electronic system the different operations are performed automatically with a minimum of manual intervention. The types of machine employed in either system usually vary from one user to another. However, most of the general concepts in data processing still remain applicable.
Data Processing Cycle
- INPUT: In this step the initial data, or output data, are prepared in some convenient form for processing. The form will depend on the processing machine. For example, when electromechanical devices are used, the input data are punched on cards; but if electronic computers are used, the input data could be recorded on any of several types of input medium, such as cards, tapes, disks, and so on.
- PROCESSING: In this step the input data are changed, and usually combined with other information, to produce data in more useful form. Thus, paychecks may be calculated from the time cards, or summary of sales for the month may be calculated from the sales orders. The processing step usually involves a sequence of certain basic processing operations.
- OUTPUT: Here the results of the preceding processing steps are collected. The particular form of the output data depends on the use of data. For example, output data may be paychecks for employees, a printed summary of monthly sales for management, or simply data to be stored for further processing at a later date.
To examine further what these terms mean, let’s consider a familiar situation. During the semester an instructor give five unit examinations. At the end of the semester the grades must be processed and the final grade sheet for the class submitted to the department. The input data are the students names and the five scores. This input is usually recorded in the instructor’s record book, with the names in alphabetical order. The instructor processes the input data by averaging the five examinations and then determining the equivalent letter grade of each student. The output data will consist of the students names and their letter grades, with the names in alphabetical order on the final grade sheet.
Expanded Data Processing Cycle
- Origination. Origination is a steps which refers to the process of collecting the original data. An original recording of the data is called a source document. For example, the source documents for the determination of student grades are the graded test papers of the students. Note that if there were any questions concerning the students final letter grade, one could go back to the sources documents, the students test papers, to see if any error had been made during the processing step.
- Distribution. This step refers to the distribution of the output data. Recordings of the output data are often called report documents. For example, the report document in the case of student grades is the class grade sheet which is forwarded to the registrar. The flow line which goes from the distribution box back to the originating box indicates that report documents may become the source documents for data processing.
- Storage. Storage is crucial in many data processing procedures. Data processing results are frequently placed in the storage to be used as input data for further processing at a later date. The two flow lines between the processing box and storage box indicate the interaction of these two steps. A unified set of data in storage is called a file. Usually a file consists of a collection of records, where each record contains similar data items, and a collection of related files is called a data base.