Windows is a computer operating system designed by Microsoft for PCs. It enables users to complete everyday tasks, edit digital photos and music, play games and much more.
A window is a separate viewing area on the screen that can be moved, resized and hidden as desired by the user. A window manager implements a windowing system.
Graphical User Interface (GUI)
GUIs enable users to interact with computers by using visual indicators and graphical representations instead of text navigation. They can be operated with a pointing device, such as a mouse, although many modern mobile devices support touch-screen interactions.
Apple’s Macintosh and Microsoft’s Windows operating systems are examples of GUIs. Xerox’s research into the user interface was further developed by Digital Research, IBM and others to create the technologies that form the basis of most modern GUIs.
The WIMP (windows, icons, menus and pointer) style of interaction provides a familiar interface that is easy for most people to learn. However, the use of graphical elements can make GUIs less efficient for experienced users who prefer keyboard shortcuts. Also, GUIs rely on screen space for graphical elements, which can limit the available space for content or require scrolling and resizing.
Memory Management
The Windows OS provides the illusion that a process has a flat virtual address space (up to 4 gigabytes). It does this by mapping those addresses into physical memory at the granularity of a page.
The OS also uses a technique called paging to manage processes that use more physical memory than the computer has installed. It does this by taking pages out of a process’s working set and writing them back to the paging file or mapped memory on disk, then bringing them back into memory when needed.
These operations take time, which is why a slow or unresponsive PC may seem to need more memory. In reality, the memory manager has simply blocked further growth of the working set until it can be compacted.
Kernel
The kernel is the heart of an operating system. It handles hardware and software applications by acting as a bridge between them. It controls memory and enables application programs to access hardware devices.
The critical code of the kernel runs in a separate area of memory called kernel space, and application software uses a different area of memory, known as user space. This separation helps prevent kernel data from interfering with application software and causing the operating system to crash or slow down.
The kernel also provides file systems, which enable an operating system to read and write files. For example, Windows, Apple and Linux all use a different version of the NTFS file system. The Windows NT kernel is considered a hybrid kernel, combining the advantages of monolithic and microkernel designs.
Process Manager
Known as Windows Task Manager before it was renamed, this system tool provides information about applications and other processes running on a windows computer. Administrators use it to manage software, including setting process priorities and processor affinity, and to monitor and troubleshoot system performance.
The Processes tab shows the current usage of CPU, disk, memory, and network resources by all programs running on your computer. Click a resource to see detailed usage graphs.
The Details tab is similar to the normal Processes tab, but it breaks up usage by user accounts—it’s handy if you have multiple people using your computer who need to track their own resource utilization. This tab also displays the services that run in the background on a windows system. You can open and close these services from here, as well as change their priority and configuration.
File System
A file system is a storage structure on a computer that organizes data by storing files in a hierarchical tree structure of directories and subdirectories. It also enables you to locate files and navigate through the directory hierarchy using a path.
NTFS is the file system that Windows uses. It supports many features that improve performance, security and reliability.
The file system also manages the space on the disk by minimizing redundant data and keeping track of free blocks. It also provides techniques to recover from failures and protect the integrity of the data.
The operating system keeps many system files hidden by default to prevent accidental or malicious changes. You can reveal these files by opening the View tab of the Options dialog box and unchecking the Hide protected operating system files check box.