01What exactly is an installation package?
When we download software, we often first get a file such as .exe, .msi, .pkg, or another format.
This file is usually not the complete final form of “the software itself.” It is an installation package or installer. It may contain the files the software needs as well as rules about where those files should go and what else needs to be set up.
Installation package
Program files, resources, configuration templates, setup instructions...
Installed in the system
Copy files + set things up + register components
02What gets put on the computer first?
The most common step is copying the files the software needs to a chosen location.
Program files
Contain the code that will run
Resource files
Images, icons, sounds, and language packs
Libraries / components
Code modules the software may call while running
Configuration and data templates
Help the software create its initial settings
On Windows, program files are often found in Program Files. macOS, Linux, and other systems have their own common places for software.
03Why create configuration and records too?
Copying files alone is not enough. The software and operating system may also need to know where the software is installed, which components it has, what its default settings are, and how to uninstall it.
Software files
Configuration and system records
Paths, versions, options, uninstall details, and more
Operating systems do this differently. Windows software may write to the registry; Linux software may use configuration files and package databases; macOS also has its own ways to manage apps and settings.
04Why does software need “dependencies”?
Some programs do not implement every feature themselves. They use capabilities provided by the operating system or shared components.
Things a program needs while running but does not necessarily include in full are often called dependencies.
A game
That is why an installer may also install Visual C++ Runtime, .NET Runtime, Java Runtime, or another component.
05How are shortcuts and file associations created?
An installer may also make settings that are more convenient for us.
Create a shortcut
An icon on the desktop or Start menu usually points to the real program location
Set a file association
For example, open .jpg files with a particular photo app by default
Add system menu entries
Some software adds context-menu items or system integrations
06Why does installing software sometimes need administrator permission?
An installer may need to change system-wide settings, such as writing to system folders, installing drivers, registering services, or changing system configuration.
07Does all software have to be installed?
No.
Some software can run after you simply extract it. It is often called portable software.
Software that needs installation
May need to copy files, create settings, and register components
Portable software
Can often run right after it is extracted
08What happens when you uninstall software?
Uninstalling can be thought of as trying to reverse the installation process.
Remove program files
Delete the main files copied during installation
Remove associations and shortcuts
Take away related system entry points
Clean up some configuration
Remove installation records and some settings
Many uninstallers intentionally keep user documents, saved games, or personal settings so they can still be used if the software is installed again.
What have you learned?
- An installation package usually includes the files software needs and instructions for the installer.
- Installing software often copies program files, resources, libraries, and configuration templates.
- An installer may also create settings, system records, uninstall details, and integrations.
- Software may depend on runtime libraries, system components, or shared environments.
- A shortcut points to the real program; deleting a shortcut usually does not uninstall it.
- File associations tell the operating system which program should open a file type by default.
- Installation may need administrator permission to change system folders or settings.
- Not all software must be installed; portable software can often run directly, though it may still create settings or caches.
- Uninstalling usually removes main program files and system records, but may keep user data and some settings.
Next question: If a computer chooses an app based on the file type, why do different files need different apps? Next: Why Do Different Files Need Different Apps?