Definition of kernel

The word "kernel" has multiple uses in different contexts, but in the world of computers, it refers to the essential component of an operating system that manages hardware resources, handles input and output requests, and schedules tasks for execution. The term "kernel" comes from the agricultural industry, where a kernel is a seed enclosed in a fruit or nut. This usage stems from the fact that, in much the same way that a kernel is hidden inside a larger structure, the OS kernel is hidden inside the larger operating system. The first computer OS kernels were developed in the 1960s and were called "monolithic" kernels because they included all necessary OS functions as a single large unit. As the demand for more advanced features and services grew, operating system designers started breaking down the kernels into smaller components called "microkernel" architectures in the early 1980s. These microkernels contained just enough hardware abstraction to run peripheral device drivers, and all other OS functions were moved into user-space processes known as servers. Though initially thought to be more scalable, flexible, and secure, it is now commonly believed that as multiple interactions between the servers and the kernel would incur significant overheads, making a unified kernel design better suited for modern OS needs. Nonetheless, the term kernel has now become an established term in computer science and has different related terms such as the "kernel thread" for the low-level threads that manage hardware and scheduling, and "kernel panic" for when the kernel fails and shuts down the system. In summary, the origin of the term "kernel" in computing can be traced back to the agricultural industry, where it refers to the essential components hidden within larger structures, and its application in computing has expanded over time as technological needs have evolved.