# Kernel Overview You can use `dmesg` command to troubleshooting kernel errors. The `dmesg` command prints messages from the kernel ring buffer. The following command, for example, presents kernel messages in a human-readable format: dmesg --human --kernel To examine kernel messages as you perform actions, such as reproducing a problem, in another terminal, you can run the command with the `--follow` option, which waits for new messages and prints them as they occur: dmesg --human --kernel --follow The kernel buffer is limited in memory size. As a result, the kernel cyclically overwrites the end of the information in the buffer from which `dmesg` pulls information. The systemd journal, however, saves the information from the buffer to a log file so that you can access older information. To view it, run the following command: journalctl -k If required, you can check the modules that are loaded on your Photon OS machine by running the `lsmod` command. For example: lsmod Module Size Used by vmw_vsock_vmci_transport 28672 1 vsock 36864 2 vmw_vsock_vmci_transport coretemp 16384 0 hwmon 16384 1 coretemp crc32c_intel 24576 0 hid_generic 16384 0 usbhid 28672 0 hid 106496 2 hid_generic,usbhid xt_conntrack 16384 1 iptable_nat 16384 0 nf_conntrack_ipv4 16384 2 nf_defrag_ipv4 16384 1 nf_conntrack_ipv4 nf_nat_ipv4 16384 1 iptable_nat nf_nat 24576 1 nf_nat_ipv4 iptable_filter 16384 1 ip_tables 24576 2 iptable_filter,iptable_nat