Introduction to computer science dessalegn Mequanint Yehuala Foreword

Parts of the Windows Desktop: 
Turn on your computer and sign in if necessary in order to display the Windows desktop. An
example of the Windows desktop is shown in the figure below, Figure 1.1.
Figure 5. Parts of Windows Desktop
The desktop shown in Figure 1.1 has icons on the left, the Taskbar on the bottom, and an open
window, which contains a document. Icons are pictures that represent programs or files. There
are icons on the desktop and on the Taskbar. The picture showing a blue sky is a wallpaper.
Any digital picture can be used as wallpaper.
• Look at your desktop. Identify the Taskbar and icons.

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Introduction To Computer Science
72
Managing Files and Folders
A file is a collection of numbers(binary digits) which have been written to your computer’s hard
drive. These numbers can be converted into a picture, a sound, text, or a set of instructions for
a program to perform certain actions. However these numbers( or the internal details on how
files are stored inside a computer) are hidden to users and a file is perceived by users as just
a label which is not the case in reality. A clue to a file’s type is given by its Icon or by its file
extension. There are innumerable file types, some of the common ones are represented here:
• .bmp – a bitmap image
• .doc – a Word document
• .wav – a sound file
• .ppt – animated slides
• .txt – plain text
• .xls – a spreadsheet
• .dbf – a database file
• A shortcut (note the arrow)
• .exe – an application (a program)
Windows allows you to view information about files in different ways.
By default if a file type is a known one, such as a Microsoft Word Document, Windows won’t
display its file extension. To view all file extensions click on Tools on the menu bar:
• Various options can be configured.
– e.g. Display compressed files and folders with alternate colours.
To display all file extensions:
untick the Hide file extensions for known file types box.
File extensions are best left alone. Opening a file with the wrong application can sometimes
damage the file. However you may at some stage need to change a file’s extension.
Folders
Folders are containers for anything on a computer including files and other folders. A path lists
the folders that have to be opened to get to the required file. Folders were called directories
on older Microsoft systems. As shown in the following figure, Figure 1.2, each of the yellow
icon is a folder. They may contain files or other folders (known as subfolders) or both. There
may be many “nestings” of folders within folders.

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