Copyright Goodheart-Willcox Co., Inc. 8 Introduction to Microsoft Offi ce it to commit fraud, which is a form of theft. Computer viruses and other malware can also be transmitted by Internet-based communication. Categories of Computers Historically, computers were grouped in one of three categories based on size: mainframes, minicomputers, or microcomputers. A mainframe is a very large high-processing computer that is used for big computing needs. A minicomputer is a computer of midrange size and performance between a microcomputer and a mainframe. A microcomputer is a computer based on a microchip for the CPU. The distinctions between the historical categories have become blurred so much that the term “minicomputer” is rarely used today. This is because the capability of microcomputers, smallest of the three, has signifi cantly expanded. Today, computers are usually categorized based on usage and cost as well as size: • supercomputers • mainframes • servers • personal computers and mobile devices Note that these are the categories of computers, which should not be confused with the four phases of the digital revolution. Supercomputers Supercomputers have processing power that can handle complex jobs beyond the scope of other computer systems. Supercomputers are the fastest computers. Examples of projects undertaken by supercomputers include breaking codes, molecular modeling, atmospheric modeling, and climate predicting. The tasks analyze enormous amounts of data. Supercomputers can be used to simulate global weather patterns, results from earthquakes, and consequences from nuclear explosions. Scientists and engineers are the primary users of supercomputers. The speed of supercomputers is usually measured in fl oating point operations per second (FLOPS). Floating point means numbers containing decimal point fractions. Figure 1-5 shows the constantly increased capability of supercomputers over the years. Mainframes Mainframe computers provide centralized storage, processing, and overall management of large amounts of data. While supercomputers are used for crunching data and numbers, mainframes are used to process and store business transactions. The speed of mainframes is measured in millions of instructions per second (MIPS). Servers A server is a special type of computer found on a network. A server stores data and responds when requested by other computers in the network. It allows other computers on the network to share programs and FYI There are many ways to classify computers. Other classifi cations or applications include the SETI project, ROCKS clusters and cluster computing, and the DWave quantum computer. Computer Ethics While you are at work or school, it is important to be respectful in your use of computer equipment. The computer is available for your use as a tool for research or to accomplish a task. It is unethical to use the computer to download copyrighted material or harass others. Ethics