TYPES OF SYSTEM CALLS

System calls can be categorized into several types based on the functionalities they provide. Here are some common types of system calls:

1.Process Control System Calls:

   -Examples:

     -fork(): Create a new process by duplicating the calling process.

     -execve(): Replace the current process image with a new one.

     -exit(): Terminate the calling process.

     -wait(), waitpid(): Wait for child processes to terminate.

2.File Management System Calls:

   -Examples:

     -open(): Open a file or create a new one.

     -read(): Read data from an open file descriptor.

     -write(): Write data to an open file descriptor.

     -close(): Close an open file descriptor.

     -lseek(): Move the read/write file offset.

3.Device Management System Calls:

   -Examples:

     -ioctl(): Perform I/O control operations on devices.

     -read(),write(): Used for device I/O.

4.Information Maintenance System Calls:

   -Examples:

     -getpid(): Get the process ID of the calling process.

     -getuid(), getgid(): Get user and group IDs of the calling process.

     -times(): Get process and system times.

5.Memory Management System Calls:

   -Examples:

     -brk(), sbrk(): Change the data segment size of a process.

     -mmap(), munmap(): Map or unmap files or devices into memory.

6.Communication System Calls:

   -Examples:

     -pipe(): Create an inter-process communication (IPC) pipe.

     -msgsnd(),msgrcv(): Send and receive messages between processes (message queues).

     -socket(): Create a new communication endpoint for networking.

7.Synchronization System Calls:

   -Examples:

     -sem_init(), sem_wait(), sem_post(): Initialize and perform operations on semaphores.

     -mutex_init(), mutex_lock(), mutex_unlock(): Initialize and perform operations on mutexes.

8.Network Communication System Calls:

   -Examples:

     -socket(), bind(), connect(): Create and manage network sockets.

     -send(), recv(): Send and receive data over a network.

9.Security System Calls:

   -Examples:

     -chmod(),chown(): Change file permissions and ownership.

     -setuid(),setgid(): Change user and group IDs for a process.

10. Time System Calls:

    -Examples:

      -time(): Get the current time in seconds.

      -gettimeofday(): Get current time with microsecond precision.

      -alarm(): Set an alarm signal to be delivered after a specified time.

These categories represent the diverse functionalities that system calls provide to user-level processes. The specific system calls available can vary between operating systems, and each system call is identified by a unique number or identifier. Developers use these system calls to perform various tasks and interact with the underlying operating system kernel.