File system handling of kernel

The kernel's file-system management provides a uniform way to store, name, organise, retrieve and protect data on storage devices (flash, SD card, disk), hiding device details from the application.

Functions:

• File operations: system calls to create, open, read, write, seek, close and delete files.
• Directory management: organises files in a hierarchical directory tree, with names and paths.
• Space allocation: tracks free and used blocks (e.g. FAT table, inodes) and allocates storage to files.
• Access control: permissions and protection for each file, and file locking to avoid conflicts between tasks.
• Mapping to devices: the file-system layer translates file requests into block reads and writes via the device driver, using buffering and caching for speed.
• Reliability: consistency checks and journaling, plus wear-levelling for flash.

Embedded kernels often use a small FAT or flash file system; a simple RTOS may have none and use raw flash instead.