Definition

Noun: 1. A request made by a program to the operating system's kernel for a service or resource. It is a fundamental mechanism that allows a user-level process to request a privileged operation, such as file access, process creation, or communication, which only the operating system's kernel is permitted to perform. 2. The specific point of interaction where a program invokes a kernel function. This action typically involves a controlled switch from user mode to a more privileged kernel mode, ensuring system security and stability.

Usage

• A is the primary interface between an application and the operating system.
• Programs use to perform operations they cannot execute directly due to hardware protection.
• Common examples include calls to open a file, allocate memory, or create a new process.

Examples

• Noun:
  • The write() system call is used to send data to a file descriptor.
  • When a program needs more memory, it makes a system call to the kernel.
  • Debugging the application revealed a failure in the open() system call.

Advanced Usage

• "to invoke a system call": to trigger or execute a system call.
  • The library function printf() eventually invokes a write system call to display text on the screen.
• "system call interface": the defined set of all system calls provided by an operating system, acting as its API (Application Programming Interface).
  • The Linux system call interface is well-documented for developers.

Variants and Related Words

• Syscall (n): A common abbreviation for "system call".
  • The program's performance was analyzed by counting the number of syscalls it made.
• Trap (n): In computer architecture, a mechanism, often involving an interrupt or exception, that switches the processor to kernel mode to handle a system call or other event.
• Kernel (n): The core part of an operating system that handles system calls, manages hardware, and provides essential services.

Synonyms

• Supervisor call: A synonym, especially in older or mainframe contexts, emphasizing the transfer of control to the supervisory part of the operating system.
• Software interrupt: A related mechanism for requesting kernel services, though the terms are not always perfectly interchangeable.

Related Phrases

• Make a system call: The act of executing a system call.
  • The application must make a system call to request network access.
• System call overhead: The performance cost associated with the context switch between user mode and kernel mode during a system call.
  • Minimizing system call overhead is crucial for high-performance computing.

Noun

1. an instruction that interrupts the program being executed and passes control to the supervisor