Ubuntu System Monitoring

Ubuntu provides the GNOME System Monitor for displaying system information and monitoring system processes: choose System Administration System Monitor. Four tabs appear on the System Monitor window: System, Processes, Resources, and File Systems. The System tab shows the amount of memory, available disk space, and the type of CPU on your system. The Resources tab displays graphs for CPU, memory and swap memory, and network usage.

The File Systems tab lists file systems, where they are mounted, and their type, as well as the amount of disk space used and how much is free. This is a fast and easy way to check how much space is left on your system.

The GNOME hardware monitor display detected temperatures for your CPU and, if available, for your graphics card. First download and install the lm-sensors package (Ubuntu main repository). In a terminal window enter sudo sensors-detect to first activate sensors. These services will detect hardware sensors on your computer. They run as Hardware Sensor services in System Administration Services. You can then download and install the sensors-applet package, the GNOME applet for sensor information. Once the applet is installed, right-click the applet icon and open its preferences window, where you can set the temperature scale and display information.

Another useful applet is the CPU Frequency Scaling Monitor, which will display CPU use (as shown in the previous illustration). This applet used the powernowd service to detect how much of the CPU is being used. Most current CPUs support frequency scaling, which will lower the CPU frequency when it has few tasks to perform. Intel CPUs will scale down to 60 percent and AMD by 50 percent.

Source of Information : McGraw Hill Ubuntu The Complete Reference