System Call

  • A system call is a mechanism using which a user program can request a service from the kernel for which it does not have permission to perform.
  • System calls are the only way a process can go into kernel mode from user mode.

System Calls

How do apps interact with Kernel?

Apps interact with Kernel using System Calls
    Eg. Mkdir FolderName
  1.  Mkdir indirectly calls the kernel and asks the file management module to create a new directory. 
  2.  Mkdir is just a wrapper of actual system calls. 
  3.  Mkdir interacts with the kernel using system calls.

Types of System Calls

  1. Process Control
  2. File Management
  3. Device Management
  4. Information Maintenance
  5. Communication Management