Source data entry devices refer to the many forms of data entry devices that are not keyboards, including pointing devices, scanning devices, magnetic stripes, smart cards, voice recognition devices, audio input, video input, and digital camera. Data source is usually on magnetic media or paper or fed directly into the processor. Pointing devices include mouse, trackball, touchpad, joystick, pen input, touch screen, light pen, and digitizer. Scanning devices include image scanners, optical readers, bar code readers, optical mark recognition, optical character recognition, magnetic ink character recognition, and fax machines. If the printed questionnaires are multiple choice questions answered using pencil marks, optical mark recognition is the best method. Optical mark recognition technology scans the printed questionnaire, detects the presence of marks, and transfers this information to the processor. In the case of telephone surveys, audio boards work best because such devices recognize the human voice and transform it into digital signals to be processed by the computer processor. An audio board is an add-on circuit board that converts analog sound to digital sound and stores it for further processing. To capture the check number at the bottom of the check, magnetic ink character recognition, a type of optical reader, is the best method because the check numbers on checks are printed with magnetic ink. (Williams, Sawyer, & Hutchinson, 1997). As for retail tags, bar code readers
capture data most accurately because most retail stores use bar codes on retail tags. A bar code consists of a set of vertical lines and spaces of different widths. The code can be translated into a 10-digit number that identifies the product manufacturer and the product number (Williams, Sawyer, & Hutchinson, 1997). Lastly, as for long documents, the best method of data input that would ensure accuracy is the image scanner. The image scanner converts the long document into digital format usable by the computer processor (Williams, Sawyer, & Hutchinson, 1997).
There are six main methods of data output. They are display screens, printers, audio-output devices, video-output devices, virtual reality devices, and microfilm (Carthy, n.d.). Display screens include monitors, cathode ray tubes, and flat panel displays. Printers could be either impact printers or non-impact printers (Williams, Sawyer, & Hutchinson, 1997).
The best method of output for handheld computers is flat panel displays because they are thin, light, and power saving (Williams, Sawyer, & Hutchinson, 1997). The best method of output for color photograph is thermal printers because they produce very high quality color printing. Alternatively, it is the trend to use softcopy output nowadays. Web sites for photo storage abound (see for example Flickr, 2006; Microsoft, 2006). A black and white inkjet printer will do for resumes since resumes do not contain colorful graphics and the quality, though lower than that of a thermal and laser printer, should suffice. As for memorandum, handwritten messages on post-it notes are convenient. Statistical reports contain graphs, tables, charts, and words. Hence, color laser printers are the best method of output. Lastly, company reports are often stored on microfilms to save space. However, for the convenience of the audience, that is, the investors, companies might publish them on the Internet in the form of soft copy.
Primary storage is random access memory that the central processing unit can access directly without the use of input and output devices. Secondary storage is memory that the