Altering the operating system

Changing something in the operating system requires the following steps:

• Remove  the write protection of the operating system disk
• Make the wanted changes to the operating system
• Reinstall the write protection 

Removing and reinstalling the write protection

To remove the write protection:

• Switch off the SeaCom 3000 and take  the SD card to a card reader of a PC computer.
• Use a file browser to locate the file cmdline and open it using a text editor.
• Remove the tekst: "boot=overlay" and save the file.
• Eject the SD card properly.
• Return the SD card to the SeaCom 3000 system, and power up. 

We are now running with an unprotected operating system, so any change You make will be persistent.

To reinstall the write protection

• Switch off the SeaCom 3000 and take  the SD card to a card reader of a PC computer.
• Use a file browser to locate the file cmdline and open it using a text editor.
• Insert the tekst: "boot=overlay" again, and save the file.
• Eject the SD card properly.
• Return the SD card to the SeaCom 3000 system, and power up. 

Changing the fixed IP address

The IP address of the SeaCom 3000 system is fixed. It is defined by the contend  of the operating system file /etc/dhcpcd.conf.

• Use remote desktop to access the system.
• Open a command line window.
• In the command window open an editor for the dhcpcd.conf file by entering the command:  sudo nano /etc/dhcpcd.conf. 
• In the bottom of the file locate the current IP address and change it to what is wanted. 
• Save the file using CTRL+X.
• Power properly down using the command:  sudo poweroff.

Enabling or disabling the DHCP server

The DHCP server is installed as a service that can be started or stopped.

To start the DHCP server use the command:  sudo service isc-dhcp-server start
To stop the DHCP server use the command:  sudo service isc-dhcp-server stop
To check the status of services installed use the command: sudo service isc-dhcp-server status