The Basics of the Windows Operating System

Windows is a popular operating system with a large developer support and many applications and games available for it. It also has a built-in security system to protect users from malware and viruses.

Its features include a graphical user interface and multitasking. It also supports various peripheral devices and Microsoft Office applications.


Almost all window systems communicate with applications by passing event information through some mechanism. These events may be triggered by user input or by the application itself. The system then executes a function in response to these events. The function, referred to as a callback, is passed parameters that specify the type of event and what to do in response. For example, when a window object is redrawn the system passes a function with three arguments: frame specifies dimensions and location of the window, title has the obvious meaning, and type (often referred to as flags) has a variety of different characteristics that are associated with particular windows such as resizing mode or whether or not it can be minimized.

An operating system also keeps track of the various input and output devices connected to the computer and decides which process will get access to what device, for how long and dealslocates devices when they are no longer required. It also performs a number of other essential tasks such as data storage, security configuration and file management.


In a window system, application programs are typically event driven. Each program starts by initializing certain structures and then suspends execution until an event occurs. When an event occurs, the program may call into a function to perform some task such as creating a window or transferring data between windows via a drag-and-drop interface.

The hardware abstraction layer hides differences in computer hardware from the rest of the operating system. It also provides a common platform for applications. This is an important feature because it allows developers to write a single program that runs on all Windows machines.

The operating system kernel manages multiprocessor synchronization and provides I/O, object management, security and process management. It is responsible for loading device drivers at bootup. It implements a kernel mode paging mechanism to transfer memory between physical and virtual addresses, and it implements a memory manager for paging in and out of physical memory to secondary storage. It also implements an interprocess communication manager that provides support for the POSIX environment subsystem.


With the introduction of the Apple Macintosh in 1984 and Microsoft Windows 3.0 in 1990, graphical user interface (GUI) programs started to reduce training time on computers and enhance productivity. Unlike the command-line interfaces that still dominated technical workstations and departmental servers, GUI programs allowed users to point to an icon on the screen to implement a command — an intuitively simpler and generally faster process than typing commands.

Every graphical Windows-based application program creates at least one window, which is the primary interface between an application and its user. Each window is displayed on the screen in a region called a “window frame” and may be sized, moved or positioned on the screen as needed.

Most windows have a title bar, menu bar, minimize button, maximize button, close button, scroll bars and a client area. The window frame and client area are defined by the window class that an application registers for when it is created.


4. Compatibility

Windows operating systems evolve over time, and older applications may not be compatible with new versions of the OS. To address these compatibility issues, Microsoft provides a feature called “compatibility mode,” which allows users to apply specific settings that will make the application behave as if it were running on an earlier version of Windows.

The Windows Hardware Compatibility List, often abbreviated as HCL, is a list of hardware devices that are compatible with a given version of the Windows operating system. Once a device passes the Windows Hardware Quality Labs (WHQL) process and is deemed to be “Certified for Windows,” it can be listed on the HCL.

IT administrators can use Microsoft’s free Windows 10 Upgrade Advisor or WhyNotWin11 to scan executable files for a particular application and assess its compatibility with the latest version of Windows. Both tools support an export function that lets IT capture the results, then filter them by machine name or other unique identifier so they can identify incompatible machines and remediate accordingly before the Windows 11 rollout.