System Call কি?
System call হল একটি programmatic পদ্ধতি যার মাধ্যমে একটি computer program, operating system এর kernel এর কাছে কোন service execute করার অনুরধ পাঠায়। System call হল process এবং operating system মধ্যের interface।
System Call যে Services গুলি দিয়ে থাকে তা হল
1. Process creation এবং management
2. Main memory management
3. File Access, Directory এবং File system management করা
4. Device এর I/O পরিচালনা করা
5. Protection
6. Networking, ইত্যাদি
System Call এর ধরন
মূলত পাঁচ ধরনের system call আছে –
- Process control
• End and Abort
• Load and Execute
• Create Process and Terminate Process
• Wait and Signed Event
• Allocate and free memory - File management
• Create a file
• Delete file
• Open and close file
• Read, write, and reposition
• Get and set file attributes - Device management
• Request and release device
• Logically attach/ detach devices
• Get and Set device attributes - Information maintenance
• Get or set time and date
• Get process and device attributes - Communication
• Create, delete communications connections
• Send, receive message
• Help OS to transfer status information
• Attach or detach remote devices
| Types of System Calls | Windows | Linux |
|---|---|---|
| Process Control | CreateProcess() ExitProcess() WaitForSingleObject() | fork() exit() wait() |
| File Management | CreateFile() ReadFile() WriteFile() CloseHandle() | open() read() write() close() |
| Device Management | SetConsoleMode() ReadConsole() WriteConsole() | ioctl() read() write() |
| Information Maintenance | GetCurrentProcessID() SetTimer() Sleep() | getpid() alarm() sleep() |
| Communication | CreatePipe() CreateFileMapping() MapViewOfFile() | pipe() shmget() mmap() |