I have never dug into low level things like cpu architectures etc. and decided to give it a try when I learned about cpu.land.
I already was aware of the existence of user and kernel mode but while I was reading site it came to me that “I still can harm my system with userland programs so what does it mean to switch user mode for almost everything other than kernel and drivers?” also we still can do many things with syscalls, what is that stopping us(assuming we want to harm system of course) from damaging our system.
[edit1]: grammar mistakes
Well hopefully you can’t harm your computer with userland programs. Windows is perhaps a bit messy at this, generally, but Unix-like systems have pretty good protections against non-superusers interfering with either the system itself, or other users on the system.
Having drivers run in the kernel and applications run in userland also means unintentional application errors generally won’t crash your entire system. Which is pretty important…
dd if=/dev/zero of=/dev/sdais a userland program, which I would say causes harm./dev/sdaaccess requires superuser/root permissions from the kernel, which means asking the kernel to lift many of the protections.Windows 7 and later, have even better anti-non-superuser protections than Unix-like systems. It’s taken a while for Linux to add a capabilities permission system to limit superusers, something that’s been available on Windows all the time.