Quantum mechanics

Multi-core processor

Computer hardware

Algorithm

Linguistics

Philosophy

Ephemeral key

Embedded system

Server

Operating system

Computation

Power (physics)

Set (abstract data type)

Parallel computing

Computer science

Code (set theory)

Distributed computing

Microcode

Very-large-scale integration

Software

Physics

Optics

Instruction set

Feature (linguistics)

Computer engineering

Focus (optics)

Reliability (semiconductor)

Programming language

We are accustomed to thinking of computers as fail-stop, especially the cores that execute instructions, and most system software implicitly relies on that assumption. During most of the VLSI era, processors that passed manufacturing tests and were operated within specifications have insulated us from this fiction. As fabrication pushes towards smaller feature sizes and more elaborate computational structures, and as increasingly specialized instruction-silicon pairings are introduced to improve performance, we have observed ephemeral computational errors that were not detected during manufacturing tests. These defects cannot always be mitigated by techniques such as microcode updates, and may be correlated to specific components within the processor, allowing small code changes to effect large shifts in reliability. Worse, these failures are often "silent" - the only symptom is an erroneous computation.

Cores that don't count