Common ISAs

Understanding instruction set architectures in modern processors

This is an easy multiple-choice question that tests foundational knowledge of processor instruction set architectures (ISAs) in current use. It appears straightforward but requires clarity on which architectures actually power contemporary devices versus those that are historical, niche, or purely theoretical.

To answer questions like this, you need familiarity with the ISAs that dominate consumer, server, and embedded markets today—which ones are actively manufactured and deployed, and which are either obsolete, experimental, or never reached wide adoption. This knowledge forms a baseline for deeper study of how processors execute instructions and how different architectural choices affect performance and power consumption.

• x86 and x86-64 lineage and market penetration
• ARM architecture variants and mobile/embedded dominance
• RISC-V and other emerging open instruction sets
• Historical ISAs and their relevance today