Difference between revisions of "CSC103: DT's Notes 1"
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Here we summarize the important points you should remember from this section. | Here we summarize the important points you should remember from this section. | ||
| − | * All we are going to find inside a computer are numbers. Binary numbers. The reason is that computers | + | * All we are going to find inside a computer are numbers. Binary numbers. The reason is that computers work with electricity, and the only way we have to store information will be using gates wired as flipflops, which allow us to store individual bits, and we can modify binary information using circuits similar to adders, and we saw that they can easily been built using logic gates. |
| − | work with electricity, and the only way we have to store information will be using gates wired as flipflops, which | + | * It is tempting to think that characters such as 'A', 'B', etc are stored in memory at some point. But actually they are not. There is a special code that assigns numbers to letters, and these are the numbers we find in memory. Again, these are binary numbers. You may have heard of the code used to assign numbers to characters. It is called ASCII, or American Standard Code for Information Interchange. It is an old code that was created for English-based languages. The Unicode is now replacing ASCII in many applications, as it allows one to represent many more languages that have different character sets (such as Japanese, Chinese, etc.) |
| − | allow us to store individual bits, and we can modify binary information using circuits similar to adders, | ||
| − | and we saw that they can easily been built using logic gates. | ||
| − | * It is tempting to think that characters such as 'A', 'B', etc are stored in memory at some point. But actually | ||
| − | they are not. There is a special code that assigns numbers to letters, and these are the numbers we | ||
| − | find in memory. Again, these are binary numbers. You may have heard of the code used to assign | ||
| − | numbers to characters. It is called ASCII, or American Standard Code for Information Interchange. It is | ||
| − | an old code that was created for English-based languages. The Unicode is now replacing ASCII in many | ||
| − | applications, as it allows one to represent many more languages that have different character sets (such | ||
| − | as Japanese, Chinese, etc.) | ||
* The processor can execute three basic types of instructions. | * The processor can execute three basic types of instructions. | ||
| − | ** '''data move''' instructions that moves information from one place in the computer to another place. The LOD and | + | ** '''data move''' instructions that moves information from one place in the computer to another place. The LOD and STO instructions are good examples of this group. |
| − | STO instructions are good examples of this group. | + | ** '''arithmetic''' instructions, such as the ADD-C or ADD, which performs the addition of some quantity to the contents of the AC register. |
| − | ** '''arithmetic''' instructions, such as the ADD-C or ADD, which performs the addition of some quantity | + | ** '''control''' instructions, such as JMP, that instructs the processor not to continue at the next memory location when it comes time to fetch a new instruction, but to go to a different address. |
| − | to the contents of the AC register. | + | * Instructions are '''very''' unsophisticated. They are very basic and operates on 1 number at a time, and modify this number using very basic operations: an addition, a subtraction, changing the value. |
| − | ** '''control''' instructions, such as JMP, that instructs the processor not to continue at the next memory | + | * However, the processor is very fast at executing these instructions. a 1 GHz (gigahertz) processor can execute 1 billion such instruction per second. If a human being capable of executing 1 action every second was asked to execute 1 billion such actions, without ever stopping for sleep, this would take that person... (let's ask Wolfram Alpha) |
| − | location when it comes time to fetch a new instruction, but to go to a different address. | ||
| − | * Instructions are '''very''' unsophisticated. They are very basic and operates on 1 number at a time, | ||
| − | and modify this number using very basic operations: an addition, a subtraction, changing the value. | ||
| − | * However, the processor is very fast at executing these instructions. a 1 GHz (gigahertz) processor | ||
| − | can execute 1 billion such instruction per second. If a human being capable of executing 1 action every | ||
| − | second was asked to execute 1 billion such actions, without ever stopping for sleep, this would take that | ||
| − | person... (let's ask Wolfram Alpha) | ||
<br /> | <br /> | ||
<center> | <center> | ||
Revision as of 18:53, 22 September 2013
--© D. Thiebaut 08:10, 30 January 2012 (EST)
