The major activities of an information system are;
(i) Input of data resource:
Data about business transactions and other events must be captured and prepared for processing by the input activity. Input typically takes the form of data entry activities such as recording and editing. End uses typically record data about transactions on some type of physical medium such as paper form, or enter it directly into a computer system. This usually includes a variety of editing activities to ensure that they have recorded data correctly. Once entered, data may be transferred onto a machine-readable medium such as a magnetic disk until needed for processing.
For example, data about sales transactions can be recorded on source documents such as paper sales order forms. (A source document is the original formal record of a transaction). Alternately, salespersons can capture sales data using computer keyboards or optical scanning devices; they are visually prompted to enter data correctly by video displays. This provides them with a more convenient and efficient user interface, that is, methods of end user input and output with a computer system. Methods such as optical scanning and displays of menus, prompts, and fill-in-the-blanks formats make it easier for end users to enter data correctly into an information system.
(ii) Processing of data into information:
Data is typically subjected to processing activities such as calculating, comparing, sorting, classifying, and summarizing. These activities organize, analyze and manipulate data, thus converting them into information for end users. The quality of any data stored in an information system must also be maintained by a continual process of correcting and updating activities.
For example, data received about a purchase can be (1) added to a running total of sales results, (2) compared to a standard to determine eligibility for a sales discount, (3) sorted in numerical order based on product identification numbers, (4) classified into product categories (such as food and nonfood items), (5) summarized to provide a sales manager with information about various product categories, and finally, (6) used to update sales records.
(iii) Output of information products:
Information in various forms is transmitted to end-users and made available to them in the output activity. The goal of information systems is the production of appropriate information products for end users. Common information products messages, reports, forms, and graphic images, which may be provided by video displays, audio responses, paper products, and multimedia. For example, a sales manager may view a video display to check on the performance of a salesperson, accept a computer-produced voice message by telephone, and receive a printout of monthly sales results.
(iv) Storage of data resource:
Storage is a basic system component of information systems. Storage is the information system activity in which data and information are retained in an organized manner for later use. For example, just as written text material is organized into words, sentences, paragraphs, and documents, stored data is commonly organized into fields, records, files, and database. This facilitates its later use in processing or its retrieval as output when needed by users of a system.
(v) Control of system performance:
An important information system activity is the control of its performance. An information system should produce feedback about its input, processing, output, and the system is meeting established performance standards. Then appropriate system activities must be adjusted so that proper information products are produced for end users.
For example, a manager may discover that subtotals of sales amounts in a sales report do not add up to total sales. This might mean that data entry or processing procedures need to be corrected. Then changes would have to be made to ensure that all sales transactions would be properly captured and processed by a sales information system.