xLow

Xlow is a term used in computing to refer to a low-overhead abstraction layer intended to simplify cross-platform access to hardware resources while preserving low latency and determinism. The exact definition of xlow varies by project, but common threads describe a minimal runtime, a compact memory model, and interfaces that permit direct control of processors, memory, interrupts, and I/O devices without imposing heavy abstractions.

Design goals typically emphasize portability across embedded, desktop, and server environments, predictability of timing, and ease of verification. A typical xlow stack may include a small kernel or microkernel, a lean scheduler, a deterministic memory allocator, and an I/O subsystem that provides device access through a uniform interface. Implementations are often written in C or Rust to maximize control and safety.

Xlow-related projects are usually experimental or niche, with diverse licensing and governance. There is no single standardized specification, and features may differ significantly between implementations. The term is sometimes used in academic papers, hobbyist blogs, and vendor demonstrations to describe approaches that avoid heavyweight runtime layers while maintaining portability and performance.

Because xlow denotes a design approach rather than a single product, practitioners refer to specific projects for details on APIs, tooling, and platform support. The concept continues to influence discussions on real-time systems, embedded development, and performance-oriented software architecture.