A modular operating system is built with its various functions broken up into distinct processes, each with its own interface. By contrast, a traditional monolithic operating system uses one static-compiled image and runs in an “all or nothing” mode. If any one element or application within a monolithic operating system fails or needs an update, the entire system must be shut down and restarted, interrupting all packet flows. The primary benefit of the modular approach is that each process operates independently, and if one of them fails or needs an update, it won’t affect any of the other functions. A modular operating system significantly improves a company’s infrastructure uptime to levels approaching the desired 99.999% (five nines) and maximizes the availability of all its business-critical applications.
The main elements of a modular operating system are a kernel and a set of dynamically loadable applications with their own discrete memory spaces. The kernel is protected from service and application failures. Each process can be monitored to determine if it is operating properly, and if necessary a faulty process can be restarted dynamically. The overall system can continue to operate throughout the fix. This maintains the uptime of the underlying infrastructure, system applications and overall operating system. This ability to start and stop an application gracefully, without impacting the entire system, enables a quick response to emerging threats and security vulnerabilities, and makes it easy to manage applications with frequent refresh cycles.
The Linux kernel is modular, which means it can extend its capabilities through dynamically-loaded kernel modules. Leading Linux enterprise distributions such as SUSE Linux Enterprise Server build on this modular Linux kernel and offer many additional modules that contain software packages which add functionality to the operating system with all the advantages of easy management and high availability.