Linux hints and tips and tweaks
Add System Monitor to the panel
Sometimes Linux programs go wrong. Although some people like to claim that Linux is ultra stable and applications never crash, the fact is that they do. Just as apps crash on Windows and the Mac. System Monitor can help you to keep an eye on what is happening in the computer and to make sure that everything is running smoothly. You can use it to spot problems.
Right click the top or bottom panel (the bar across the top or bottom of the screen), and select Add to Panel. In Ubuntu you can only select System Monitor, but in other Linux distros you may have a wider choice. For example, in Mandriva 2010 running KDE, there is a choice of System Load Viewer, System Monitor - CPU, System Monitor - Hard Disk, System Monitor - Network, System Monitor - RAM, System Monitor - temperature, and plain old System Monitor. System Load Viewer is the best.
let's look at Ubuntu. When you add an item to the panel, you'll see an icon, so right click it and select Preferences. Tick the items you want to monitor and then set the update interval. If it updates too often, it puts too much load on the system and it can slow down other tasks, so set it to one or two seconds (1000 or 2000 milliseconds). You will see mini scrolling charts in the panel and these show the items you chose to monitor. Let the mouse hover over one of the charts and you'll see a pop-up tip box that gives more details.
You can easily see the CPU usage, memory free and used, download speed and so on. When a program goes wrong, it is common for the CPU usage to rise, the used memory to rise, disk access and network usage to fall. You'll soon get to know what is normal and what is not normal.
A crashed program can run the processor at 100%, for example. However, the System Monitor usage indicator only shows total CPU usage, so if a program running on one core is stuck, you'll see 25% usage on a quad core system. It might look like there's little activity going on, but the core with the crashed app is running flat out! Watch out for that. CPU usage rises and falls and it produces a chart with lots of spikes. If you see the CPU chart stuck at 25%, 50% or 75%, then that means one or more cores is tied up in a crashed app.
Left clicking one of the mini scrolling charts opens the full System Monitor utility and if you select the Processes tab and look down the CPU column you'll probably see the problem app. Rebooting is a good way to clear the system and start afresh.
