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The six elements of a computer and communications systemProcedures are descriptions of how things are done, steps for accomplishing a result. Sometimes procedures are unstated, the result of tradition or common practice. You may find this out when you join a club or are a guest in someone’s house for the first time. Sometimes procedures are laid out in great detail in manuals, as is true, say, of tax laws. When you use a bank ATM – a form of computer system- the procedures for making a withdrawal or a deposit are given in on-screen messages. In other computer systems, procedures are spelled out in manuals. Manuals, called documentation, contain instructions, rules, or guidelines to follow when using hardware or software. When you buy a microcomputer or a software package, it comes with documentation, or procedures. Nowadays, in fact, many such procedures come not only in a book or pamphlet but also on a computer disk, which presents directions on your display screen. Many companies also offer documentation online. System element 3: Data/Information The distinction is made between raw data, which is unprocessed, and information, which is processed data. Units of measurements of data/ information capacity include kilobytes, megabytes, gigabytes, and terabytes. Though used loosely all the time, the word data has some precise and distinct meanings. “Raw data” Versus Information Data can be considered the raw material – whether in paper, electronic, or other form – that is processed by the computer. In other words, data consists of the raw facts and figures that are processed into information. Information is summarized data or otherwise manipulated data that is useful for decision making. Thus, the raw data of employees’ hours worked and wage rates is processed by a computer into the information of paychecks and payrolls. Some characteristics of useful information may be another person’s data. Some characteristics of useful information are that is relevant, timely, accurate, concise, and complete. Actually, in ordinary usage the words data and information are often used synonymously. After all, one person’s information may be another person’s data. The “information” of paychecks and payrolls may become the “data” that goes into someone’s yearly financial projections or tax returns.
4. Output Hardware Output hardware consists of devices that translate information processed by the computer into a form that humans can understand. We are now so exposed to products output by some sort of computer that we don't consider them unusual. Examples are grocery receipts, bank statements, and grade reports. More recent forms are digital recordings and even digital radio As a personal computer user, you will be dealing with three principal types îf output hardware—screens, printers, and sound output devices. Two sizes of diskettes are used for microcomputers. The older and larger size is 5J/4 inches in diameter. The smaller size, now by far the most common, is 31/2 inches. The smaller disk, which can fit in a shirt pocket, has a compact and rigid case and actually does not feel "floppy" at all. To use a diskette, you need a disk drive. A disk drive is a device that holds and spins the diskette inside its case; it "reads" data from and "writes" data to the disk. The words read and write are used a great deal in computing. Read means that the data represented in magnetized spots on the disk (or tape) are converted to electronic signals and transmitted to the memory in the computer. Write means that the electronic information processed by the computer is recorded onto disk (or tape). The diskette drive may be a separate unit attached to the computer, particularly on older models. Usually, however, it is built into the system cabinet. Most newer PCs have one or two 3l/2-inch drives and perhaps one 5'/4-inch drive.
Date: 2015-04-20; view: 1270
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