Image42.A simplified introduction to computer systems

We begin here a scary page… Let's start with a simple statement: Software developers and end- user s do not speak the same language…


But then … how are we going to make it ? Easy: we read the beginner 's handbook ! 39

Within a short period of time, computers became an essential tool of the modern life. One issue is that information and education don't follow the technical progress at the same pace, nor the needs of the users.

Therefore, it is difficult for a "new user" to discover the full capabilities of its computer. Moreover we use generally only few applications.

We will try to simplify this universe as far as possible, in order for you to make the most of your computer and to enjoy the capabilities of Debian.

How does a computer work ?

One launches applications, clicks on icons, types text in … One needs a computer, a screen, a keyboard, a mouse.

In this handbook, we will explain to you the basic manipulations in order to use your mouse 40 and your keyboard 41.

What use for a computer ?

It seems difficult to summarize in few sentences the whole scope of information technology. However its usage is somewhat clear:

And this is exactly the knowhow you are going to learn with the beginner 's handbook 42 .

2.1.Test your level of computer skills

Keep in mind that this manual is not cast in stone … Our advices are only suggestions regarding your computer knowledge …

First of all, you are free 43 !

Importantly, be as honest as possible: we are all beginners in one domain or another (personally, I am unable to change the injectors in the carburettor of my car) and it is not a fault. The issue is raising only because computers are taking a large space in our lives, and penalize the newbies. But we are here to change all that !

The goal of this manual is not to transform you in GNU/Linux sysadmin (short for system administrator), but simply give you the tools to utilize your computer as you want !

Outright beginner ?

44 You never or rarely used a keyboard ? You still wonder why you must "open a window" and what is this "drag and drop" concept ? Please continue reading this manual and follow its guidance 45. You will learn how to:

Novice user ?

You are a Windows® user and/or you have a little experience with GNU/Linux, but you never installed it: it is the right time to choose your Debian (chap.4) and discover the main interface of your future system.

Basic user ?

You have already used a Debian derivative and/or another free distribution, and you know exactly what you need. Let's jump directly to the serious stuff with the actual installation in chapter 5.

2.2.The mouse

The mouse is the physical interface which let you move the pointer on the screen : the mouse moves are synchronized with those of the of the little arrow (the pointer ) 48 on your desktop.
There are different types of
mouse 14 ; We will take here the example of the classical mouse with two buttons and a scrolling wheel .

2.2.1.Identify the clicks depending on their positions and double-click

The left-click 49 (or simple-click) is the most common and is used to point to (or select) either a folder, or a file or an image, which can then be open with a double-click (done by quickly pressing twice the mouse left-button). This left-click is also used to send commands to the computer (validating a choice for example) when one presses on the "button" or something else sensitive to the click (like the cross closing a window, for example).

The right-click 50 is used to open a contextual menu (a variable list of options, depending on the software used and the "object" pointed at by the mouse ) in order to modify a file, a folder, a configuration …

The middle-click or scrolling-wheel 51 is used for scrolling and quick copy. If your mouse has neither a middle button nor a scrolling wheel , the " middle-click " can be emulated by pressing on the two (left and right) buttons at the same time.

2.2.2.Actions executed with the mouse

One thing that you SHOULD NEVER DO is to click several times on a button if you think that nothing happens. It is very possible that an application won't start "immediately", it is very depending on your hardware and the application being launched. As an example, a web browser takes significantly more time to start up, than the file manager.

Note that most of the actions executed with the mouse are also possible with the keyboard : either directly with a function key, or by using a keyboard shortcut ( see chap.2.3.2 ). a window

To close a window, left-click on its "close" button, usually symbolized by a cross in the top right corner of the window.

Closing a window with the mouse a window

To move a window on your screen simply move your pointer on the title bar (the top banner of the window) then press and hold the left-click
pointer will then change its usual look: from 53 to 54
The window will then follow the
mouse motion until you release the left button.

If you don't have access to the title bar, you can use the special [Alt] key on your keyboard together with the mouse left-click to grab and move your window. a window

Windows are automatically open on the screen with a certain size. To close them, we have seen already that we need to click on the close button symbolized by a cross.

To resize a window , you need to move your cursor on the borders of the window or , even better, on one of the bottom corners.
pointer will then change its usual look: from 55 to 56 or 57 depending on its left or right position. When the look of the pointer changes, press the left-button and move the mouse to resize the window like you want.

An alternative solution consists in using use the special [Alt] key on your keyboard. Move the pointer inside the window, then press together the [Alt] key and the right-button of the mouse. Then you will be able to resize the window.

To maximize a window , double-click (click twice quickly with the mouse left-button) on the title-bar (when using the GNOME environment) or use the maximize button located next to the close button, if present (and it is the case on most of the desktops).

To graphically move or copy your data, it is enough to "drag" them across the screen and "drop" them where you want (this is the graphical equivalent of the mv command).

Example: to move a file you just downloaded into another folder, press the left-button the file in question, and while you hold the right-button, you move the mouse into the destination folder and then you release the mouse button:

drag and drop : point to the file to be moved

drag and drop : hold the button while moving the mouse

drag and drop : move the mouse into the destination folder

drag and drop : release the button selection

Put the cursor at the beginning or at the end of the text segment you want to select, then hold the left-button, and move the mouse over the text you want selected. Then release the mouse button.

You can also double-click (click twice quickly on the mouse left-button) on the first word you want to select and then move the cursor.

text selection within the Gedit application

If you are fast enough, a triple-click will select the entire line or paragraph. and paste a selection

With the right-button : a right-click will display a contextual menu giving you the choice among several actions, one of them being the requested copy/paste . Put the cursor within the selected segment, right-click and choose the "copy" action. Then move the cursor where you want to paste the selected text, right-click again and choose "paste".

Copy and paste a text segment: copy the selection

Copy and paste a text segment: cursor on destination, right-click > paste

Copy and paste a text segment: selection pasted

With the middle-button : this is the fastest method. Once the text segment is selected, you just need to move the pointer where you want to paste the selection and do a middle-click . The copy is immediate. of several items

If you want to move or delete several items within a folder, you can select them together.

To select a group of contiguous items: press and hold the left-button, move the mouse to drag a frame around them and release the button when they are all selected. Then you can act on the selection like explain previously (copy/paste or contextual menu)

Selecting several folders under Gnome

To select non contiguous items, you can:

Selection of several non-contiguous items in a Nautilus window

2.3.The keyboard

The keyboard is the main physical interface to enter data in your computer . But it is not the just the device which let you enter some words in the Internet search bar, or work with a word processor. It includes also some special keys, called modifier keys , which allow you to execute quick actions by modifying the behavior of the "normal" keys. The combinations of some "special" keys with other "normal" keys form the keyboard shortcuts .

Default QWERTY keyboard layout

Example of layout for an English keyboard (cc-by-sa)

2.3.1.The modifier keys

The "non-alphanumeric" keys of the keyboard give you access to extended functionalities during action or edition phases. From the simple carriage return within a text editor with the [Enter] key, to the launch of a Help window with the [F1] key, find hereafter some descriptions of these special keys:


In this example pressing together the key [Alt] and "f" will open the "File" menu, [Alt] and "e" the "Edit" menu, [Alt] and "v" the "View" menu, etc … You can also navigate in the menu with the direction arrows of the keyboard.

2.3.2.Keyboard shortcuts

Note that the shortcuts are made by pressing down the keys together, at the same time: to copy a selection, press and hold the [Ctrl] key, then press the [c] key. You can then release both keys, a clone of your selection is stored in the "clipboard" (a special buffer located in the memory of the operating system).




Copy the current selection (in the "clipboard")


Cut the current selection (and save it in the "clipboard")


Paste the latest copy/cut selection (the current content of the "clipboard")


Find a word or an expression

[Ctrl]+[+/-] or [Ctrl]+Mouse-scrolling-wheel

Zoom in/out of the screen display


Close the active window


Jump from open window to the next one


Open the Help function of the active application


Switch to full-screen mode

71Note that some functionalities are not only available on text segments (like copy/paste), but on files also: if you select several pictures in your 'Pictures' folder, make a [Ctrl]+[c] and then a [Ctrl]+[v] on your desktop, your selected pictures will be copied there 72 . In the same way, [Ctrl]+mouse-scrolling-wheel will zoom in or out the content of your Internet navigator, as well as the content of a system file manager window.

2.3.3.Special characters

Keyboards can't contain as many keys as available characters. In order to write the particular characters in English, it is necessary to combine the keys like the shortcuts (simultaneous pressing of the keys)

First, a preview of the QWERTY's hidden keys:

special charaters available on QWERTY keyboard layout (cc-by-sa)

Each symbol is associated with a key combination. So to write "®", you'll have to simutaneous press [AltGr] & [r].

Available c h aracters on [c] key

If you are not comfortable with simultaneous pressure exercises, you can always copy and paste special characters from a characters table15 or from one listed above.

Alphabetic characters





















































Others characters
























Some fun 75
































































Online exercises

mouse exercices:

keyboard exercices:

2.4.The users

One of the great strengths of the GNU/Linux systems is their user management. The separation of rights and responsibilities provides a better security when executing system administration tasks or exchanging data on the net. Small explanation …


76 Generally YOU are the user , of course. Sometimes one talks about the Chair-To-Keyboard interface (abbreviated CTKI), since it's very true that you are sitting between the chair and the keyboard, or the mouse. When you work on your computer, it does not see you. It feels only the actions made by a user with a login -name and sometimes a password .

Each user is allowed to perform a certain number of actions. Your user can, for example, use the keyboard and the mouse, read and write some documents (files), but not all of them . We call that rights : to execute administrative tasks, one must obtain the rights of the root administrator ( see chap.3.8.3 ).


77 Only one user has all the rights , it is the administrator . This special user is able to execute some tasks (in particular for the system administration ) that other normal user s cannot perform by themselves. But a single mistake in an operation made by this root user could potentially beak the whole system.

At home, on your desktop computer , you can use your computer both as a normal user and as an administrator . Some well defined actions have to be made in order to switch from one role to the other, like entering the root administrator password see chap.3.8.3 ).

Separate to secure

78 This clean distinction, which, by the way, does not always exist under other operating system s, strengthen the stability and security of the Debian GNU/Linux system, as mentioned at the beginning of this manual. When working as simple/normal user you cannot make your computer unusable (brick it), and the potential viruses cannot infect the whole system.

More details on rights and permissions in the chapter 3.7 .