The argument is basically that it does too much and as the motto of Unix was basically “make it do 1 thing and that very well”, systemd goes against that idea.
You might think it is silly because what is the issue with it doing many things. Arguably, it harms customization and adaptability, as you can’t run only 2/3 of systemd with 1/3 being replaced with that super specific optimisation for your specific use case. Additional, again arguably, it apparently makes it harder to make it secure as it has a bigger attack surface.
At a high level, microkernels push as much as possible into userspace, and monolithic kernels keep drivers in kernel space
There are arguments for each e.g. a buggy driver can’t write into the memory space of another driver as easily in a micro kernel, however it’s running in the same security level as userspace code. People will make arguments for both sides of which is more secure
Monolithic kernels also tended to be more performant at the time, as you didn’t have to context switch between ring 0 and ring 1 in the CPU to perform driver calls - we also regularly share memory directly between drivers
These days pretty much all kernels have moved to a hybrid kernel, as neither a truly monolithic kernel nor a truly micro kernel works outside of theoretical debates
The argument is basically that it does too much and as the motto of Unix was basically “make it do 1 thing and that very well”, systemd goes against that idea.
You might think it is silly because what is the issue with it doing many things. Arguably, it harms customization and adaptability, as you can’t run only 2/3 of systemd with 1/3 being replaced with that super specific optimisation for your specific use case. Additional, again arguably, it apparently makes it harder to make it secure as it has a bigger attack surface.
Sustemd is modular though, you don’t have to use every subsystem. The base init system and service manager is very comprehensive for sure.
And funnily enough, the kernel doesn’t follow the unix philosophy either as far as I know.
I have heard that before in a joke setting, I would love to hear genuine arguments for and against it.
The debate is as old as Linux itself, and well documented.
It doesn’t seem to be a debate. “Microkernels are better” “yes but I don’t have the time for it” but thanks
At a high level, microkernels push as much as possible into userspace, and monolithic kernels keep drivers in kernel space
There are arguments for each e.g. a buggy driver can’t write into the memory space of another driver as easily in a micro kernel, however it’s running in the same security level as userspace code. People will make arguments for both sides of which is more secure
Monolithic kernels also tended to be more performant at the time, as you didn’t have to context switch between ring 0 and ring 1 in the CPU to perform driver calls - we also regularly share memory directly between drivers
These days pretty much all kernels have moved to a hybrid kernel, as neither a truly monolithic kernel nor a truly micro kernel works outside of theoretical debates