You don't mention what you are looking for in terms of a "running configuration file". In Unix/Linux there are many of these. Most of them can be found in the /etc directory or its subdirectories but not all of them are located in /etc.
On NVRAM.
Boot Configuration Data (BCD)
NVRAM is that router component in which start up configuration file is stored.
NVRAM
It will boot into ROMMON mode. It will ignore the start-up configuration file. It will look for the start-up configuration file on the TFTP server. It will attempt to load the start-up configuration file that is stored in NVRAM.
The running configuration on a router or switch is stored in the device's RAM (Random Access Memory) while it is running. It's a temporary configuration that is lost when the device is powered off or restarted. To view the running configuration, you can use the "show running-config" command in the device's CLI (Command Line Interface).
wr or copy running-config startup config
The running configuration file on S1 will be saved via TFTP to a file named tokyo-config.
SDRAM
The Motherboard configuration is stored in the BIOS setup
Configuration settings file can be viewed either in notepad or browser depending on the type of configuration file. If the configuration file has extension - "INI", then it can be viewed in notepad or textpad. If the configuration file has extension - "XML", then it can be viewed both in Notepad and Browser.
Configuration files are typically stored in the /etc directory. They can, of course, be anywhere the implementer wishes them to be as long as the process knows where to find them.