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| projects:archevo:isa [2021/04/20 14:43] – [IPLOC] Owen Mellema | projects:archevo:isa [2021/04/21 00:03] (current) – [ISAs in ArchEvo] Owen Mellema |
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| ===== What is an ISA? ===== | ===== What is an ISA? ===== |
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| An //ISA//, short for Instruction Set Architecture, is the convention that allows programmers to talk to computers. The programmer can write a string of bits, give it to a CPU, and the CPU will do something. It is the most basic form of programming language. In fact, all programming languages are eventually turned into a series of bits based off of the ISA. 9The series of bits is sometimes called Assembly Language, but that isn't important here.) | An //ISA//, short for Instruction Set Architecture, is the convention that allows programmers to talk to computers. The programmer can write a string of bits, give it to a CPU, and the CPU will do something. It is the most basic form of programming language. In fact, all programming languages are eventually turned into a series of bits based off of the ISA. (The series of bits is sometimes called Assembly Language, but that isn't important here.) |
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| ===== Brittleness ===== | ===== Brittleness ===== |
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| ISAs that are practically used are generally //brittle//. This means that if a random bit flips in an instruction, the results will likely be catastrophic (for the execution of the program, that is). Although this isn't a purposeful choice on the parts of the designers of these ISAs, it isn't necessarily a bad thing. Consider, for example, an ATM. if a "cosmic ray" hits the CPU, and an instruction has a bit flip, we (or, at least, the bankers) don't want it to continue running as if nothing had happened, as this could lead to a loss of money. Instead, they would rather the program fail, and just be rebooted. | ISAs that are practically used are generally //brittle//. This means that if a random bit flips in an instruction, the results will likely be catastrophic (for the execution of the program, that is). Although this isn't a purposeful choice on the parts of the designers of these ISAs, it isn't necessarily a bad thing. Consider, for example, an ATM. If a "cosmic ray" hits the CPU, and an instruction has a bit flip, we (or, at least, the bankers) don't want it to continue running as if nothing had happened, as this could lead to a loss of money. Instead, they would rather the program fail, and just be rebooted. |
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| Brittleness is caused by two main factors. | Brittleness is caused by two main factors. |
| 00000000 => ( 0, 0) | 00000000 => ( 0, 0) |
| </code> | </code> |
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| | ===== ISAs in ArchEvo ===== |
| | The following is a list of the ISAs in ArchEvo: |
| | * [[projects:archevo:asia|ASIA]] |
