Basic ICT skills and working in Linux

Once your system boots, you'll be presented with the login prompt. Log in using the personal login and password you selected during the installation process. If you have a desktop environment installed, you are taken to the desktop after logging in. This is where you'll use your applications. Here is an example of Debian desktop environment, with an empty desktop and the top bar.

The top bar provides access to your windows and applications, your clock and calendar, and the system menu. In the system menu in the top bar, you can manage your system settings and your computer. To access your windows and applications, just click the Activities button or move your mouse pointer to the top-left corner. You can see your windows and applications in the overview.

You can search your applications, files and folders in the overview. On the left side of the overview, you will find the dash. The dash shows you your favorite and running applications. The grid button at the bottom of the dash shows you all the applications installed on your computer. The right-most side of the screen is the workspace selector. Workspaces act like virtual desktops, which can be used to organize your work. For example, you could have web browser on one workspace, and the work you are doing on a different workspace. When you leave your computer, you can lock your screen to prevent other people from using it. You can also switch users without logging out completely to give somebody else access to the computer, or you can suspend or power off the computer from the menu. When you lock your screen, or it locks automatically, the lock screen is displayed.

A terminal is a text input point in a computer that is also called the Command Line Interface (CLI). Hardware terminals are no longer produced as physical devices. To emulate these terminals, there are terminal emulators. Emulation is the ability of a computer program to imitate another program or device. A terminal emulator is a software program that emulates a terminal in modern computers that use graphical user interfaces and provide interactive access to applications that run only in the command line environments. Here is a screenshot of GNOME Terminal program.

Virtualization extends the capabilities of one physical computer so that it can run multiple operating systems, inside multiple virtual machines, at the same time. As an example, you can run Windows on your Linux, run Linux on your Windows PC, and so on. You can install and run as many virtual machines as you like. The only practical limits are disk space and memory. Virtualization can significantly reduce hardware and electricity costs. Most of the time, computers today only use a fraction of their potential power. A lot of hardware resources as well as electricity is thereby wasted. So, instead of running many such physical computers that are only partially used, one can pack many virtual machines onto a few powerful hosts and balance the loads between them. Once installed, a virtual machine and its virtual hard disks can be considered a container. This way, one can freely experiment with a computing environment. If something goes wrong after installing software or infecting the guest with a virus, you can easily delete and create another virtual machine. When dealing with virtualization, it helps to understand some terminology. Host operating system is the operating system of the physical computer (host). Guest operating system is the operating system that is running inside the virtual machine (guest). Virtual machine is the special environment for your guest operating system while it is running. In other words, you run your guest operating system in a virtual machine. It is possible to run multiple virtual machines on one physical computer and connect to it over the network. Cloud computing takes this approach and allows you to have a virtual machine in a remote datacenter that you don't own. Cloud computing vendors can offer computing resources at prices better than what it would cost you for your own hardware, space, and cooling. You can also get file storage, or even software. The key is that you pay only for what you use, rather than buying it yourself. Linux plays a pivotal role in cloud computing. Most virtual servers are based on some kind of Linux kernel and Linux is often used to host the applications behind cloud computing services.