COMPUTER

Computer-Aided Design and Manufacturing

The amount of wind pressure on a car is simulated by computers with Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) programs. Red indicates high wind pressures and blue indicates low pressures.

The Cray-1 Supercomputer (designed by Seymour Cray of Cray Research, Eagan, Minnesota) was the first computer capable of performing over 100 million floating-point calculations per second. Of the many technological problems that had to be solved, one of the most important was how to remove the heat generated by the high-speed logic. This was accomplished by mounting the circuits on vertical plates that were cooled by a freon refrigeration system. Although faster machines have now been built, the Cray-1 continues to be used for mathematical studies of very complex problems, such as speech analysis, weather forecasting, and fundamental questions in physics and chemistry. The Cray-1 also leaves its mark as the informal unit of measure for newer supercomputers, some of which are now projected to equal 1,000 ‘Crays’.

A close-up of a smoke detector’s circuit board reveals its components, which include transistors, resistors, capacitors, diodes, and inductors. Rounded containers house the transistors that make the circuit work. Transistors are capable of serving many functions, such as amplifying and switching. Each transistor consists of a small piece of semiconducting material, such as silicon, that has been "doped", or treated with impurity atoms, to create n-type and p-type regions. Invented in 1948, transistors are a fundamental component in nearly all modern electronic devices.

A typical computer system consists of a central processing unit (CPU), input devices, storage devices, and output devices. The CPU consists of an arithmetic/logic unit, registers, control section, and internal bus. The arithmetic/logic unit carries out arithmetical and logical operations. The registers store data and keep track of operations. The control unit regulates and controls various operations. The internal bus connects the units of the CPU with each other and with external components of the system. For most computers, the principal input device is a keyboard. Storage devices include external floppy disk drives and internal memory boards. Output devices that display data include monitors and printers.