Modern Technology

Personal computer

Personal computers (PCs) fall into two main types: IBM-compatible PCs, known simply as PCs, and Apple Macintosh PCs, known as “Macs”. They differ in the way files and programs, and the user’s access to them, are organized, and programs must be tailored for each type. However, in most other respects PCs and Macs have much in common. Both contain microchips, or integrated circuits, that store and process data. The “brain” of any PC is chip known as central processing unit (CPU), which performs mathematical operations in order to run program instructions and receive, store, and output data. The most powerful personal computer CPUs today can perform more than a billion calculations a second. Data can be input via CDs, USB memory sticks, and other storage media. Highly portable laptop and network PCs are also in widespread use. Most PCs are able to communicate with many other devices , including digital cameras and smart phones.

Tablet computer

By the early 1990s electronic circuitry had been miniaturized to such an extent that it was possible to make small handheld computing devices. The first of these was the Personal Digital Assistant (PDA), which offered features including an address book, calendar, and notepad. In recent years, PDAs have been overtaken by smart phones with Internet and email access. A related product is the e-book reader, which stores book in digital form and uses “electronic paper” to mimic the appearance of ink on real paper. An e-book reader no bigger than an thin paperback can store several thousand digital books in its memory. The most recent handheld computing device is the tablet computer. This looks like a thin flat display, but it is actually a complete computer. Tablet computers are typically controlled by touch-sensitive screen and have a wireless link to other computers and the Internet. They run software applications, or apps, downloaded from the Internet. The most popular tablet computer currently is the Apple iPad. It has multi-touch interface that enables its screen to detect the movements of fingertips. As well as selecting options and apps by touching the screen, images can be enlarged or shrunk by moving fingertips apart or together on the screen.

Flatbed scanner

Scanners convert physical images into electronic form, allowing them to be sent over the Internet, displayed on a website, stored on a computer, and manipulated using specialized software. Scanners work by detecting and analysing light reflected from an opaque image, such as photographic print. Some can also scan photographic transparencies by analysing light that has passed through the image. Flatbed scanners contain a unit, called the scan head that contains a lamp, mirrors, a lens, and an array of CCDs (Charged-Coupled Devices). The carriage passes beneath the image;