|
|
|
|
|
|
|
power or not enough power). Rather than saying enough or not enough, they simplify it to yes or no. Yes or no, or true or false, can be represented as 1 or 0. By convention, 1 means true or yes, but that is just a convention; it could just as easily have meant false or no. |
|
|
|
|
|
|
|
|
Once you make this great leap of intuition, the power of binary becomes clear: With 1s and 0s you can represent the fundamental truth of every circuit (there is power or there isn't). All a computer ever knows is, Is you is, or is you ain't? Is you is = 1; is you ain't = 0. |
|
|
|
|
|
|
|
|
Once the decision is made to represent truth and falsehood with 1s and 0s, binary digits (or bits) become very important. Since early computers could send 8 bits at a time, it was natural to start writing code using 8-bit numberscalled bytes. |
|
|
|
|
|
|
|
|
Half a byte (4 bits) is called a nybble! |
|
|
|
|
|
|
|
|
|
With 8 binary digits you can represent up to 256 different values. Why? Examine the columns: If all 8 bits are set (1), the value is 255. If none is set (all the bits are clear or zero the value is 0. 0255 is 256 possible states. |
|
|
|
|
|
|
|
|
It turns out that 210 (1,024) is roughly equal to 103 (1,000). This coincidence was too good to miss, so computer scientists started referring to 210 bytes as 1KB or 1 kilobyte, based on the scientific prefix of kilo for thousand. |
|
|
|
|
|
|
|
|
Similarly, 1024 * 1024 (1,048,576) is close enough to one million to receive the designation 1MB or 1 megabyte, and 1,024 megabytes is called 1 gigabyte (giga implies thousand-million or billion). |
|
|
|
|
|
|
|
|
Computers use patterns of 1s and 0s to encode everything they do. Machine instructions are encoded as a series of 1s and 0s and interpreted by the fundamental circuitry. Arbitrary sets of 1s and 0s can be translated back into numbers by computer scientists, but it would be a mistake to think that these numbers have intrinsic meaning. |
|
|
|
|
|