Three Key Concepts

1. PURPOSE OF A COMPUTER: TURNING DATA INTO INFORMATION Very simply, the purpose of a computer is to process data into information. • Data: Data consists of the raw facts and figures that are processed into information—for example, the votes for different candidates being elected to student-government office. • Information: Information is data that has been summarized or otherwise manipulated for use in decision making—for example, the total votes for each candidate, which are used to decide who won.

2. DIFFERENCE BETWEEN HARDWARE & SOFTWARE You should know the difference between hardware and software. • Hardware: Hardware consists of all the machinery and equipment in a computer system. The hardware includes, among other devices, the keyboard, the screen, the printer, and the “box”—the computer or processing device itself. Hardware is useless without software. • Software: Software, or programs, consists of all the electronic instructions that tell the computer how to perform a task. These instructions come from a software developer in a form (such as a CD, or compact disk) that will be accepted by the computer. Examples are Microsoft Windows and Office XP/Vista.

3. THE BASIC OPERATIONS OF A COMPUTER Regardless of type and size, all computers use the same four basic operations: (1) input, (2) processing, (3) storage, and (4) output. To this we add (5) communications. • Input operation: Input is whatever is put in (“input”) to a computer system. Input can be nearly any kind of data—letters, numbers, symbols, shapes, colors, temperatures, sounds, pressure, light beams, or whatever raw material needs processing. When you type some words or numbers on a keyboard, those words are considered input data. • Processing operation: Processing is the manipulation a computer does to transform data into information. When the computer adds 2 2 to get 4, that is the act of processing. The processing is done by the central processing unit—frequently called just the CPU—a device consisting of electronic circuitry that executes instructions to process data. • Storage operation: Storage is of two types—temporary storage and permanent storage, or primary storage and secondary storage. Primary storage, or memory, is the internal computer circuitry that temporarily holds data waiting to be processed. Secondary storage, simply called storage, refers to the devices and media that store data or information permanently. A hard disk or CD/DVD is an example of this kind of storage. (Storage also holds the software—the computer programs.) • Output operation: Output is whatever is output from (“put out of”) the computer system—the results of processing, usually information. Examples of output are numbers or pictures displayed on a screen, words printed out on paper by a printer, or music piped over some loudspeakers. • Communications operation: These days, most (though not all) computers have communications ability, which offers an extension capability— in other words, it extends the power of the computer. With wired or wireless communications connections, data may be input from afar, processed in a remote area, stored in several different locations, and output in yet other places. However, you don’t need communications ability to write letters, do calculations, or perform many other computer tasks.