Question

1) What is SYSTEMD? What is INIT? How are they different?

2) What is an INTERRUPT?
3) What is the difference between a RUNAWAY process and a ZOMBIE process?

4) What is the difference between ACL and PERMISSION BITS?

Answer 1

1) The SYSTEMD software suite is defined to be a fundamental building block for the Linux operating system which contains the systemd system as well as service manager that is being used for bootstraping the user space as well as user process management. This also aims to unifying the service configuration and the behavior via the Linux distributions

Whereas on the other hand Unix based computer operating system is considered as the first process which started with respect to the booting of the computer system and also it is a daemon process which continues to run until the system is being shut down.

When considering the unix based OS then Init is the first-ever process which gets started while the booting of the computer system and is also the direct or indirect ancestor of the other relevant processes which adopts to the other orphaned processes.

Whereas the systemd is considered as the parent process of all the other processes which is either directly or indirectly the first process which starts at the boot which is being assigned a pid=1 and is also referred to as all the package, or the libraries or the utilities around the daemon which was developed for overcoming the init processes shortcomings.

2) When the digital computer is looked for, an interrupt is the input signal to the processor which indicates the events which would need immediate attention. This is more of a signal alert which the processor, as well as requestor to the process, has which the currently executed code is interrupted.

3) A zombie process gets created while a parent process would not use the wait system call after the child expires or dies for reading the exit status.

While the runaway process is the kind of process which enters the infinite loop as well as spawns the new processes which as a result can cause an overflow in the considered proc table and can cause the other processes to fall with no more process error statement.

4) When the share point or the shared folder is referred then the POSIX permission helps one to allow in setting the permission only for that of the Owner, one individual Group as well as others while the ACL would provide an additional option for setting the permission for multiple individuals and multiple groups for the shared items. ACL contains many types of permission.

POSIX permission bit is much easier to use and also for the home user needs while ACLS are finer degree of control via the access to the files as well as folders and also becomes complicated to manage.