Mastering Linux Kernel Development

Real-time clock (RTC)

Keeping track of the current time and date is very crucial, not just to let the user know about it but to use it as a timestamp for various resources in the system, specifically, files present in secondary storage. Every file has metadata information such as the date of creation and last modification date, and every time a file is created or modified, these two fields are updated with the current time in the system. These fields are used by several apps to manage files such as to sort, group, or even delete them (if the file hasn't been accessed a for long time). The make tool uses this timestamp to determine whether a source file has been edited since the last time it accessed it; only then is it compiled, otherwise ...