järjestelmäkut

Järjestelmäkut is a Finnish term that translates to "system call" in English. It refers to a programmatic way in which a computer program requests a service from the operating system's kernel. These services can include a wide range of operations such as reading or writing files, creating or terminating processes, managing memory, and communicating with other programs.

When a program needs to perform an operation that requires privileged access or interaction with hardware, it cannot do so directly. Instead, it must issue a system call. The operating system's kernel, which has the necessary privileges, then handles the request. This mechanism ensures that user programs operate in a controlled and secure environment, preventing them from interfering with the system's integrity or accessing data they are not authorized to.

System calls are a fundamental concept in operating systems. They act as an interface between user-level applications and the kernel, providing a standardized way for software to interact with the underlying hardware and system resources. Different operating systems have their own distinct sets of system calls, though many common functionalities are provided across various platforms. The specific implementation and invocation of system calls can vary between different operating systems and programming languages.