The relationship between Linux device driver and the whole hardware and software system

In addition to network devices, character devices and block devices are mapped to file system files and directories through the file system's API

Open (), close, write (), read (), and other accessible character devices and block devices.

A block device is more complex than a character device, where a disk/flash file system, such as Ext3, is first created, and these files

The system defines the organization of files and directories on the storage media.

The application can use the Linux system call interface or the C standard library, which is more recommendable for code portability considerations.

The C library function itself is also implemented through the system call interface, such as C library functions, fopen (), fclose (), Fread (), fwrite () will respectively

Invoke the operating system's API, open (), close (), read (), write ().

The relationship between Linux device driver and the whole hardware and software system