SystemD is the startup and service manager on most, but not all, linux distros.
I like this answer: short and accurate enough.
systemd handles a lot more than starting/stopping things, but that’s the core of it. It is used by many (most?) up to date linux distros, but some stick to the older and simpler initd.
Yes, but with a caveat: systemd is included, but by default something else is used instead (don’t remember what). Systemd can be enabled if you so wish.
Source: I used mx a few years back. I may not be up to date on this.
Probably yes. The mx iso used to come with an unused but available systemd that you could boot into instead of the default sysvinit, but now they have 2 different isos for the 2 different systems. If the iso is recently downloaded, you would have had to pick which to use.
@mmcintyre thanks for sharing this. So, I can directly download a systemd format of mx linux and work on either xfce or fluxbox.
It manages your services at boot and allows you to start and restart them. If the HAL is the buffer between the kernel and the hardware, then systemd provides a layer between the kernel and the user/services. It’s a super generic answer full of holes, but it’s easy to start with
The https://systemd.io/ main page has a pretty succinct answer to this:
systemd is a suite of basic building blocks for a Linux system. It provides a system and service manager that runs as PID 1 and starts the rest of the system.
systemd provides aggressive parallelization capabilities, uses socket and D-Bus activation for starting services, offers on-demand starting of daemons, keeps track of processes using Linux control groups, maintains mount and automount points, and implements an elaborate transactional dependency-based service control logic.
Other parts include a logging daemon, utilities to control basic system configuration like the hostname, date, locale, maintain a list of logged-in users and running containers and virtual machines, system accounts, runtime directories and settings, and daemons to manage simple network configuration, network time synchronization, log forwarding, and name resolution.
If someone has to ask what systemd is, do you expect him / her to understand this answer?
Not every term, certainly. But the first paragraph is a good at describing the primary purpose. And the last paragraph shows the breadth of services provided. I shared it thinking it could be the basis for further learning, or exploration of the project website to go and read more about it.
The first and last program that your Linux system runs, unless you replace it with a different program that will effectively do the exact same thing.
