As its name implies, the kernel is at the core of each UNIX system and is loaded in whenever the system is started up -referred to as a boot of the system.
It manages the entire resources of the system, presenting them to you and every other user as a coherent system. You do not need to know anything about the kernel in order to use a UNIX system. This information is provided for your information only.
Amongst the functions performed by the kernel are:
- managing the machine's memory and allocating it to each process. - scheduling the work done by the CPU so that the work of each user is carried out as efficiently as is possible. - organising the transfer of data from one part of the machine to another. - accepting instructions from the shell and carrying them out. - enforcing the access permissions that are in force on the file system.