Dictionary of Computer and Internet Terms phần 5

3. một mô tả của bất kỳ hình ảnh có chứa các sắc thái của màu xám là màu đen và trắng. Hy Lạp bảng chữ cái được sử dụng trong Hy Lạp cổ đại và hiện đại, alpha beta g delta . Ω và delta alpha b '. ω. Các chữ cái Hy Lạp thường được sử dụng như những biểu tượng toán học. Đối với γ bảng chữ cái Hy Lạp hoàn thành, xem trang | 219 Green PC FIGURE 122. Graphics tablet Photo courtesy of Wacom Technology grayscale 1. a series of boxes filled with a range of black tints from pure white to 100 black. A grayscale is used to test a printer monitor scanner or printing press. 2. scanner terminology the range of grays in an image as measured by the scanner. 3. a description of any image that contains shades of gray as well as black and white. Greek the alphabet used in ancient and modern Greece A Br A . Q and a p Ys . ro. Greek letters are often used as mathematical symbols. For the complete Greek alphabet see page 6. Contrast CYRILLIC LATIN. greeking the use of random letters or marks to show the overall appearance of a printed page without showing the actual text. With computers greeking is used when the page is displayed too small for the text to be readable on the screen. FIGURE 123. Greeking Green Book the Philips Sony standard for multimedia interactive compact discs not including personal computer software . Green PC a personal computer that draws little electrical power when idle even though still turned on. A Green PC typically stops spinning its hard Gregorian calendar 220 disk and shuts down power to the monitor if several minutes elapse with no keyboard activity. See also ENERGY STAR. Gregorian calendar the calendar system presently in use introduced by Pope Gregory in 1582 and adopted in England in 1752 and in Russia in 1918. It is exactly like the Julian calendar except that years divisible by 100 are not leap years unless they are also divisible by 400. The Gregorian calendar thus follows the earth s revolution around the sun more accurately than the Julian calendar did. See LEAP YEAR. grep the UNIX command that reads a text file and outputs all the lines that contain a particular series of characters. For example the command grep abc myfile reads the file myfile and outputs every line that contains abc. Instead of specifying the exact characters to be searched for you can give a .