Windows Setup

Windows Setup is the main setup process used to install Windows.

Windows 9x
In Windows 9x versions, .CAB files are used for the installation. Mostly known .CAB installation files include:


 * WIN95.CAB, WIN98.CAB and WINME.CAB: They contain the main system apps and files.
 * DRIVER.CAB: Contains the driver files for Windows.
 * NET.CAB: Contains networking and internet components.

Windows Server 2003 and earlier
Since their inception, NT-based version used INF files to describe the file system layout and registry settings along with individually compressed files, similarly to other Microsoft products at the time. The user interface underwent multiple changes until its deprecation during Windows Vista development, but the key principles stayed the same. Due to the operating system files being stored in the  directory on x86 architecture media, it is also often called the i386 setup, although different architectures stored the files in different directories.

The i386 installation process builds new folders under the local disk where it depends on where the files will be copied to such as Windows and System32 folders. Files are compressed under their 8.3 file format-named files (where the last letter of the specific file after the dot is replaced with an underscore symbol). Those files get unpacked with the original files getting copied to their respective folders.

In Windows XP's x64 SKUs, the AMD64 folder contains the system files used for installation. However, the i386 folder still exists.

Setup graphical assets are stored in WINNTBBA.DLL and WINNTBBU.DLL.

Windows Vista and later
Windows Longhorn build 4001 introduced the WIM installation format. This installation format boots the operating system via WinPE which launches the setup interface, the WIM file gets imaged to the computer's hard disk and the rest of the image gets worked around that.

Even though it was first introduced with Windows Vista, Windows XP can be imaged as WIM as well. Examples can be seen in the Windows Embedded for Point of Service and Windows Fundamentals for Legacy PCs operating systems.

Setup graphical assets are stored in spwizimg.dll on Windows Vista and later; Windows Longhorn pre-reset builds store them in win32ui.dll and win32uitheme.dll.

The ESD (Electronic Software Distribution) format has been introduced with Windows 8.1. Compared to WIM, ESD files are smaller and cannot be mounted or edited without converting to WIM first.