1. Data Representation A series of eight bits is called a byte. A byte can be used to represent a number or a character. As you’ll see in the following table, the byte that represents the integer value 0 is 00000000, with all eight bits “off” or set to 0. The byte that represents the integer value 1 is 00000001, and the byte that represents 255 is 11111111.

2. Data Representation

3. Microcomputers commonly use the ASCII code to represent character data. Each byte represents a unique character such as the number 8, the letter A, or the dollar sign symbol $. For example, the phrase “Hi there!” is represented by 9 bytes. Each of the seven letters requires one byte, and the space and the exclamation point also require one byte each. As you’ll see in the following table, the ASCII code for the letter A is the byte 01000001, and the ASCII code for the lowercase letter a is 01100001.

4. Data Representation

5. As a computer user, you don’t have to know the binary representations of numbers, characters, and instructions—the computer handles all the necessary conversions internally. However, because the amount of memory in a computer and its storage capacity are expressed in bytes, you do need to be aware of how data is represented to have an idea of how much data you can store in your computer.

6. Data Representation You will often see the symbols KB, MB, and GB in reference to both processing and storage capacities. A kilobyte (KB) is approximately one thousand bytes, a megabyte (MB) is about one million bytes, and a gigabyte (GB) is approximately one billion bytes. 1 KB = 2 10 bytes = 1,024 bytes 1 MB = 2 20 bytes = 1,048,576 bytes 1 GB = 2 30 bytes = 1,073,741,824 bytes