TABLE OF CONTENTS Text does not occupy much space in the computer. An average book, consisting of a million characters, can be stored uncompressed in about 1 Mbyte, because each character of text occupies one byte (the Colophon at the end of the book illustrates this with accurate data from the book itself).
|
| Exercise 7.1: It is a handy rule of thumb that an average book occupies about a million bytes. Explain why this makes sense. |
|
Answers
|
| 7.1: An average book may have 60 characters per line, 45 lines per page, and 400 pages. This comes to 60 45 400 = 1,080,000 characters, requiring one byte of storage each. |
In contrast, images occupy much more space, lending another meaning to the phrase "a picture is worth a thousand words." Depending on the number of colors used in an image, a single pixel occupies between one bit and three bytes. Thus, a 4 Mpixel picture taken by a typical current (2006) digital camera occupies between 512 Kbytes and 12 Mbytes before compression. With the advent of powerful, inexpensive personal computers in the 1980s and 1990s came multimedia applications, where text, images, movies, and sound are stored in the computer, and can be uploaded, downloaded, displayed, edited, and played back. The storage requirements of sound are smaller than those of images or movies, but bigger than those of text. This is why audio compression has become important and has been the subject of much research and experimentation...
