Microsoft Windows


Microsoft Windows

Microsoft Windows is a range of closed source proprietary commercial operating environments for personal computers and servers. The range was first introduced by Microsoft in 1985 and eventually has come to dominate the world personal computer market. All recent versions of Windows are fully-fledged operating systems.

Windows was developed for IBM PC-compatible computers (these were based on Intel x86 architecture), and today, almost all versions of Windows are made for this hardware-platform (although Windows NT was written as a cross-platform system for Intel and MIPS processors, and later appeared on the PowerPC and DEC Alpha architectures). The popularity of Windows made Intel CPUs more popular and vice versa. In fact, the term Wintel became used to describe PC-compatible computers running a version of Windows.



The term Windows is used as a collective term for several generations of products, which can be classified into the following categories:

  • 16-bit operating environments. Although they are often thought of as just graphical user interfaces or desktops, mostly because they use MS-DOS for file system services, 16-bit Windows versions already have their own executable file format and provide their own device drivers (graphics, printer, mouse, keyboard and sound). Most importantly, from the beginning they allow the user to (non-preemptively) multi-task graphical applications, something which competitors like GEM do not offer. Finally, they implement an elaborated segment-based software virtual memory scheme, which allows to run applications larger than available memory: code segments and resources are swapped in and thrown away when useless or memory becomes scarce and data segments move in memory when a given application has relinquished processor control. Examples include Windows 1.0 (1985) and Windows 2.0 (1987) and its close relative Windows/286.
  • Hybrid 16/32-bit operating environments. Windows/386 introduced a 32-bit protected mode kernel and virtual machine monitor. For the duration of a Windows session, it provided a device virtualization for the disk controller, video card, keyboard, mouse, timer and interrupt controller. The user-visible consequence was that it became possible to preemptively multitask multiple MS-DOS environments in separate windows (graphical applications required switching the window to full screen mode). Windows applications were still multi-tasked cooperatively inside one of such real-mode environments. Windows 3.0 (1990) and Windows 3.1 (1992) perfected the design, notably thanks to virtual memory and loadable virtual device drivers (VxDs) which allowed them to share arbitrary devices between multitasked DOS windows. Most important, Windows applications could now run in 16-bit protected mode (when Windows was running in Standard or 386 Enhanced Mode), which gave them access to several megabytes of memory and removed the obligation to participate in the software virtual memory scheme. They still ran inside the same address space, where the segmented memory provided a degree of protection, and multi-tasked cooperatively. For Windows 3.0 Microsoft also rewrote critical operations from C into assembly, making this release faster and less memory-hungry than its predecessors.
  • Hybrid 16/32-bit operating system. With the introduction of 32-Bit File Access in Windows for Workgroups 3.11, Windows could finally stop relying on DOS for file management. Leveraging this, Windows 95 introduced Long File Names, reducing the 8.3 DOS to the role of a boot loader. MS-DOS was now bundled with Windows; this notably made it (partially) aware of long file names when its utilities were run from within Windows, but angered the competition. The most important novelty was however the possibility of running 32-bit multi-threaded preemptively multitasked graphical programs. There were three releases of Windows 95 (the first in 1995, then subsequent bug-fix versions in 1996 and 1997, only released to OEMs, which added extra features such as FAT32 support). Microsoft's next OS was Windows 98; there were two versions of this (the first in 1998 and the second, named "Windows 98 Second Edition", in 1999). This was an evolutionary enhancement, in much the same relation to Windows 98 as Windows 3.1 had been to 3.0. In 2000, Microsoft released Windows Me, which used the same core as Windows 98 but adopted the visual appearance of Windows 2000, as well as a new feature called system restore, allowing the user to set the computer's settings back to an earlier date. Compared to previous upgrades, comparatively few people bothered to switch to ME: by this time most power users had already jumped over to the NT family. This can be defended by the fact that Microsoft left little time for Windows Millennium to become popular before announcing their next version of Windows.
  • 32-bit operating systems originally designed and marketed for higher-reliability business use with no DOS heritage. The first release was Windows NT 3.1 (1993, numbered "3.1" to match the Windows version and to 1-up OS/2 2.1, its main competitor at the time), which was followed by NT 3.5 (1994), NT 3.51 (1995), and NT 4.0 (1996); the latter of which introduced the Windows 95 interface. Microsoft then moved to combine their consumer and business operating systems. Their first attempt, Windows 2000, failed to meet their goals, and was released as a business system. The home consumer edition of Windows 2000, codenamed "Windows Neptune", ceased development and Microsoft released Windows ME in its place. Eventually "Neptune" was merged into their new project, Whistler, which later became Windows XP. XP finally rendered DOS obsolete, and since then a new business system, Windows Server 2003, has expanded the top end of the range, and the forthcoming Windows Longhorn will complete it. Windows CE, Microsoft's offering in the mobile and embedded markets, is also a true 32-bit operating system.
  • 64-bit operating systems, the newest category, are designed for AMD's AMD64 CPU architecture, Intel's Intel Architecture 64-bit, and EM64T. The 64-bit Windows family comprises Windows XP Itanium edition and x64 Edition and Windows Server 2003; Windows XP Professional and server x64 editions were released on April 25, 2005. Itanium editions already came out in 2002. Early indications are that Windows Longhorn, the projected successor to Windows XP, will be released in both 32-Bit and 64-Bit versions.


A typical Windows XP desktop.
A typical Windows XP desktop.

The most obvious feature of the more recent Windows versions (since Windows 95 and NT 4.0) is the desktop, which is similar to the "Workplace Shell" introduced by IBM for OS/2 2.0 in 1992, an object-oriented GUI running on the OS/2 Presentation Manager. The Windows desktop has produced a significant change in the way people and computers interact; it is possible to perform many common tasks with very little computer knowledge, including some quite complex ones.

Another quite significant feature of Windows since Windows 95 is the Start Button and Start Menu, which gives users of any skill level immediate access to all of their installed programs, and many of the other features of the operating system.

Windows XP introduced a new visual style dubbed "Luna", which updated the classic Windows style (a plain grey box look) with a more graphical appearance. The new style features bold colors and a larger titlebar and start button, leading many to call it the "playskool" interface (after a popular brand of children's toys) [1] ( [2] ( [3] ( and others to call it the "Teletubbies" interface (after the children TV show Teletubbies, also partly because of Windows XP's default wallpaper, a grassy plain with a blue sky, which resembles the set of the TV show) [4] ( Users can still elect to use the old Windows 95/2000 visual style.

There is a view that modern operating systems need to cater to the vastly increased user base with a lower average computer skill level and the increased power and complexity of modern computer systems. Therefore, some technically savvy users accuse the Windows interface of isolating the user from too much of the inner workings of the computer, making it more difficult to control and configure some system features, although many such features can be now controlled also from the command-line or by scripting. However, this has always been an issue to some extent with GUI operating systems, and, to a lesser extent, almost all operating systems, by definition.


Thought to be installed on over 90% of personal computers, Windows has achieved enormous market penetration due in large part to the domination of MS-DOS in the early days of PC compatible computers (IBM-PC clones), and also because it is the primary platform for Microsoft Office and gaming software programs used by many microcomputer users. Although some of these factors have faded over the years (such as the sunset of the MS-DOS, the ability of third-party software like Open Office to create and/or modify Microsoft Office documents, or the porting of notable games to Macintosh and Linux), these factors helped create a dedicated early userbase.

Microsoft's operating system has also benefited from the fact that they are one of the few companies that are willing to license their OSes to hardware manufacturers. (For example, Apple is loath to license Mac OS X and Sun does not license Solaris to anyone.) Before, companies who wanted to be in the computer business had to create their own operating system (such as the Amiga) or use a OS without a GUI (like MS-DOS or CP/M); even an exclusive license was significantly cheaper than developing a new operating system and creating a software base. Thus, Microsoft won much early support.

Due to Microsoft's exclusive licensing agreements with many computer vendors, Windows today comes pre-installed on most computers as a bundled OEM version, making it the default choice for much of the market. Most consumers do not delete Windows and install another operating system. For some consumers, Windows is the only valid option as their computing environment is mandated by their workplace; additionally, the unfamiliarity of most other operating systems limits the desire to switch to other operating systems. Additionally, a growing part of the computer market (the "AOL generation") lacks the technical knowledge needed to install an operating system.

Finally, the software base of programs available for the Windows family of operating systems (generally greater than that of all other operating systems combined) has become the single largest self-perpetuating reason for the popularity of Windows. In recent years, many companies have started up with the sole intention of releasing Windows software; the fact that there is already a large customer base in place is reason enough for such companies to only spend resources on Windows software development. In turn, the fact that many companies are supporting Windows exclusively is reason for many customers to choose Windows.


Security has been a major weakness of Windows for many years. Most modern operating systems were designed for security in a multi-user and/or networked environment and have a relatively small number of security issues. Windows was originally designed for ease-of-use on a single-user PC without a network connection, and did not have security features built in from the outset. Combined with occasionally flawed code (such as buffer overruns) Windows has been the successful target of worms and virus writers numerous times. In June 2005, Bruce Schneier's Counterpane Internet Security reported that it had seen over 1,000 new viruses and worms in the previous six months.

Some say Microsoft Windows gets more than its fair share of attacks simply because it is the dominant desktop operating system. Others say it gets more attacks because poor engineering design makes it such an easy target: its monolithic and entangled structure is in stark contrast to the rigorous modularity and carefully defined layers of its rivals. Microsoft publicly admitted their ongoing security problems shortly after the turn of the century and (according to their press statements) now claims to regard security as their number one priority.

Microsoft releases security patches through its Windows Update service approximately once a month, although critical updates are made available at shorter intervals. In Windows 2000 and Windows XP, updates can be automatically downloaded and installed if the user elects to do so.

Many security experts are advising Windows users to take steps to increase the security of their systems. A study conducted by Kevin Mitnick and marketing communications firm, Avantgarde, found that an unpatched Windows XP system only lasted 4 minutes on the Internet before it was compromised. [5] ( The AOL/National Cyber Security Alliance Online Safety Study of October 2004 determined that 80% of Windows users were infected by at least one spyware/adware product. [6] ( Much documentation is available describing how to increase the security of Microsoft Windows products. Typical suggestions include deploying Microsoft Windows behind a hardware firewall, running anti-virus and anti-spyware software, and installing patches as they become available through Windows Update. Some suggest replacing specific programs which are often targeted by crackers with alternatives, such as replacing the web browser Internet Explorer with Mozilla Firefox, and replacing the email client Microsoft Outlook with Mozilla Thunderbird.

In 2001, Microsoft started talking about a controversial security initiative called Palladium. The system has since been renamed "Next Generation Secure Computing Base". Palladium is a system intended to allow a program to verify that it is unmodified, and is running on "trusted" hardware with "trusted" drivers and a "trusted" architecture. This, in theory, assures the software that it is running on unmodified software and hardware. Palladium has a particular use in DRM systems. A side effect will be to lock out "untrusted" operating systems at the hardware level: this is likely to impact Linux in particular, since there is no single canonical Linux which can be certified, and many users consider the ability to customize the system one of its main attractions. Some conspiracy theorists hold that this is the secret reason behind the system, although in practice it is unlikely that Microsoft will try to prevent Linux vendors such as Red Hat from having their products certified. As of 2004, Palladium has not resulted in any commercial products.

Current versions

  • Windows CE for embedded systems including Consumer Electronics products (note: CE is a different operating system from DOS and Windows NT/2000/XP, and Microsoft makes the source code available)
  • Windows Mobile for smart phones and PDAs (a version of Windows CE)
    • Portable Media Center for Digital Media Players
  • Windows XP for desktops and notebooks
    • Windows XP Starter Edition, for new computer users in developing countries
    • Windows XP Home Edition, for home desktops and notebooks
    • Windows XP Home Edition N, as above, but without a default installation of Windows Media Player, as mandated by an EU ruling
    • Windows XP Professional Edition, for business and power users
    • Windows XP Professional Edition N, as above, but without a default installation of Windows Media Player, as mandated by an EU ruling
    • Windows XP Professional x64 Edition, for PC's with 64-bit processors (based on Windows Server 2003)
    • Windows XP Tablet PC Edition, for notebooks with a touch screen or a pen-sensitive screen
    • Windows XP Media Center Edition for desktops and notebooks with an emphasis on audio, video, and PVR capability
  • Windows Server 2003 for servers
    • Small Business Server for first server installations (up to 2 processors)
    • Web Edition for basic web serving (up to 2 processors)
    • Standard Edition for smaller server applications that don't require clustering (up to 4 processors)
    • Enterprise Edition for larger server applications, and clustering (up to 8 processors)
    • Datacenter Edition for mainframe like servers (up to 128 processors)
    • Storage Server for Network Attached Storage Devices
  • Windows XP Embedded for embedded systems

Past versions

Cancelled versions

  • 1996 May 3 - Windows Nashville (windows 96) (cancelled) (Became windows 95B.)
  • 1997-1998 - Cairo (a "true object-oriented OS") planned after Windows NT; if released would be similar to DesktopX (but at a lower level) (Became Windows NT 4)
  • 1999 December - Windows Neptune was sent out to beta testers but was never released. Should have been successor to Windows 2000.

Future versions

  • 2006 - Windows codename "Longhorn" is scheduled to be released.
  • 20102012 - Windows codename "Blackcomb".
  • Windows Eiger - is in early development, designed for old machines.

Emulation and virtual machine software

Emulation or the use of "virtual machines" allow the use of some Windows applications without using Microsoft Windows.

See also

External links

History of Microsoft Windows
Windows: 1.0 | 2.0 | 3.x | NT | 95 | 98 | Me | 2000 | XP | Server 2003 | Server 2003 R2 | CE | Mobile | Longhorn | Blackcomb

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