How can a computer represent words and letters using bits?

Answer 1

Using a character code (e.g. ASCII, EBCDIC, UNICODE). Different character codes use different bit patterns for the same character.

Bytes are collections of zeros and ones (known as bits). Group in eight together to form one 8 bit byte. Basically variations of these zeros and ones can represent large numbers, if a one is in a certain spot on a byte: 128, 64, 32, 16, 8, 4, 2, and 1. One byte can represent any number from 0 to 255 depending on the placement of the zeros and ones. 00000001 = 1 (i.e. one 1), 00000011 = 3 (i.e. a one place and a two place = 3), 00000101 = 5 (i.e. a one place and a four place equals 5), etc. 11111111 = 255. Add zero as a number (00000000) and you a have 256 possibilities, which you can see is exponential of 2.

Each character is given a number. The computer has a 'look up' table that correlates the number with the character. Another part of the system controls the graphics with the character and describes how to build it on the screen.

This part can be controlled by the user by installing different Fonts.

The ability to represent large numbers allows languages to be created that ultimately tell the computer to display letters and words. As far as your screen is concerned, it is made up of rows and columns of dots called pixels and the process of drawing is just as you would do on a piece of graph paper filling in the individual blocks.

Obviously going from zeros and ones to high level languages involves a lot of programming that would take an expert to explain as well as an educated student of computers to understand.

Answer 2

Computers are digital machines which simply means they only understand numeric data. This means that everything we can store in a computer (numbers, text, images, videos, music, etc) must be represented by some numeric value. This is a process known as "digitising". All real-world data must be digitised before it can be stored in a computer's memory.

The computer doesn't actually understand numbers (it is a machine -- it doesn't actually "think"), but it can represent them simply by converting the number to its binary form. For instance, the decimal value 42 is represented by the 8-bit binary value 00101010. As far as the computer is concerned this is simply an array of "switches" where 3 are "on" and 5 are "off". What that particular sequence of switches actually represents depends on its interpretation. It could mean the decimal value 42, but it could also mean character 42 in the ASCII character table, which is the asterisk symbol (*).

Even the symbol itself must be digitised, and this is achieved by creating a bitmap, known as a glyph, which is a two-dimensional matrix of bits, each representing a pixel which is either on or off (the colour is not important, but we can think of the pixels being black and white where white is the background colour).

Each glyph maps to an index value (a number) thus to store a letter we simply need to store its index. Collections of glyphs are stored in ASCII code pages of 256 characters each, where the first 128 characters are the same (only differing in style). UNICODE encodings are similar to ASCII but use more bytes per character, thus allowing many more character encodings. The first 128 encodings are the same as those in ASCII code pages, however UNICODE also supports variable length encodings such that the first 128 ASCII characters can be encoded in 1 byte without any translation.

Answer 3

The computer doesn't understand letters, numbers and symbols, which is human readable. The computer only understands binary 1's and 0's (1 is on, 0 is off).