systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system.
The key commands or arguments you will use with systemctl are the following:
list-units [PATTERN...] List loaded units
At first my BIOS said the card may not work right because there is no more option ROM space.
I disabled the Option ROM for both LSI 1068 and 2008 chipsets, Network Boot ROM and most other PCI slots, Serial Port, etc... and the message went away but the card still does not work properly.
But it still cannot initialize the card properly (does not work):
[ 33.943272] NVRM: This PCI I/O region assigned to your NVIDIA device is invalid:........
If you move your hard drive(s) around to other computers/servers, you'll find that your eth0 keeps getting higher, the first time it will become eth1 and then eth2 etc and even higher if your server has dual or quad NICs. The reason is that udevd basically assigns eth0 tot he first NIC it finds and remembers it, if it encounters a NIC with a different MAC, it assigns it one higher (eg. eth1).
See the example below, I have eth2 now so how do I fix it?........