Most of the PiKVM settings are done through configuration files. All configuration changes must be made from under the `root` user (i.e. the administrator).
The PiKVM memory card is mounted in read-only mode. It protects the filesystem from damage in case of sudden power outage. To edit any files and make changes, it is necessary to remount the file system to the read-write mode.
* To enable write-mode, run command `rw` (under `root`).
* To disable it, run command `ro`.
* If you receive the message "Device is busy", perform `reboot`.
In this handbook, you will often find instructions for editing configuration files. The simplest and most beginner-friendly text editor is `nano`, but you can also use `vim`.
Most of the PiKVM configuration files are located in the `/etc/kvmd` directory.
The `/etc/kvmd/main.yaml` file defines the platform config and **you should never edit it**. To redefine system parameters use the file `/etc/kvmd/override.yaml`. All other files that are also not recommended for editing have read-only permissions.
In the `/etc/kvmd/meta.yaml` file you can specify some information regarding the host that this PiKVM manages.
!!! tip
A complete list of all parameters can be viewed using the `kvmd -m` command.
Files with the suffix `*.yaml` uses the [YAML syntax](https://docs.ansible.com/ansible/latest/reference_appendices/YAMLSyntax.html)
and describes a parameter tree with key-value pairs of different types.
To define the parameters within one section, an indent of 4 spaces is used.
Comments starts with the `#` symbol.
!!! warning "Only 4 spaces should be used for indentation"
Be careful when editing YAML and follow this rule.
Invalid indentation or tabs instead of spaces will cause an error when starting the services.
??? example "Sections under the same keys should be merged"