#code #hardware

Computers have different processor architectures, which can be categorized based on their instructions set.

Instruction Set Architectures (ISA) define the communication rules between the software and the hardware, and especially the set of instructions that a particular hardware can handle.

There are two main ISAs : - Clomplex Instruction Set Computers (CISC) include complexe instructions, like multi-step and energy consuming instructions. This is used by most Intel processors. - Reduced Instruction Set Computers (RISC) have a limited instruction Set, that take only 1 clock cycle to complete.

Here are the main processor architectures available today: - ARM processors use the RISC architecture. (ARM = Advanced RISC Machine). It exists in 32bits and 64bits - Intel x86 (or x86-32, or x32) processors use the CISC architecture. It is the 32 bit version of the processor, limited to 4Go of RAM and that is used on older computers - AMD64 (or x86-64, or x64) is the newer, 64bit version of the instructions set. It is retro-compatible with the 32 bit version.