Microsoft Windows

Categories: Operating systems | Windowing systems | Microsoft Windows

Microsoft Windows is a range of operating environments and operating systems for personal computers and servers. The range was first introduced by Microsoft in 1985 as an add-on to MS-DOS to counter Apple's new system, the Apple Macintosh, which used a graphical user interface (GUI). Microsoft Windows eventually came to dominate the world personal computer market with a market share estimated to be still around 90% for desktop personal computers. All recent versions of Windows are fully-fledged operating systems. Windows is proprietary closed source software: Microsoft Corporation owns the software's copyright and controls its distribution.

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.

Microsoft Windows versions

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. The early versions of Windows were just graphical user interfaces or desktops, mostly because they used the underlying MS-DOS for file system services and all operating processes. Soon, 16-bit Windows versions would have their own executable file format and provide their own device drivers (graphics, printer, mouse, keyboard and sound). Unlike DOS, the Windows environment allowed all users to execute multiple graphical applications at the same time (cooperative multitasking). Finally, they implemented a software segment-based virtual memory scheme which allowed the GUI 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 a real-mode environment. 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 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). In 2000, Microsoft released Windows Me (Me standing for Millennium Edition), 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. It was not a very well received implementation, and many user problems occurred. ME was considered a stopgap to the day both product lines would be seamlessly merged. Microsoft left little time for Windows Me to become popular before announcing their next version of Windows which would be called XP.

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 one-up OS/2 2.1, IBM's flagship OS codeveloped by Microsoft and Windows NT's main competitor at the time), which was followed by NT 3.5 (1994), NT 3.51 (1995), and NT 4.0 (1996); the latter implemented the Windows 95 user 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. Since then, a new business system, Windows Server 2003, has expanded the top end of the range, and the forthcoming Windows Vista 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, Professional x64 Edition, and Windows Server 2003; Windows XP Professional and Server 2003 x64 editions were released on April 25, 2005. Itanium editions already came out in 2002. Early indications are that Windows Vista, the projected successor to Windows XP, will be released in both 32-bit and 64-bit versions.

See also: List of Microsoft Windows versions.

Microsoft Windows version release history

• 1985 - Microsoft Windows 1.0 is introduced in November and initially sold for $100.00
• 1987 - Windows 2.0 released December 9th.
• 1987 - Windows/386 is introduced December 9th
• 1988 - Windows/286 introduced June
• 1990 - Windows 3.0 released May 22. MS Windows 3.0 Full was priced at $149.95 and the upgrade was priced at $79.95
• 1991 - Windows 3.0 with multimedia released in October
• 1992 - Windows 3.1 released in April and sells more than 1 Million copies within the first two months of its release.
• 1992 - Windows for Workgroups 3.1 released in October
• 1993 - Windows NT 3.1 released August
• 1993 - The number of licensed users of Microsoft Windows totalled more than 25 Million.
• 1994 - Windows for Workgroups 3.11 released in February
• 1994 - Windows NT 3.5 released in September
• 1995 - Windows NT 3.51 released in June
• 1995 - Windows 95 (Win 4.0) released in August and sold more than 1 Million copies within 4 days.
• 1996 - Windows NT 4.0 released in August
• 1996 - Windows CE 1.0 released in November
• 1997 - Windows CE 2.0 released in November
• 1998 - Windows 98 released in June
• 1998 - Windows CE 2.1 released in July
• 1999 - Windows 98 Second Edition released on May 5th
• 1999 - Windows CE 3.0 released
• 2000 - Windows 2000 released on February 17th
• 2000 - Windows ME (Millennium Edition) released on June 19th
• 2001 - Windows XP released on October 25th
• 2003 - Windows Server 2003 released on March 28th
• 2005 - Windows XP x64 professional released
• 2006 - Windows Vista is slated for release.
• 2007 - Windows Server "Longhorn" is slated for release.

Interface

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, some quite complex, with very little computer knowledge.

Another quite significant feature of Windows since Windows 95 is the Start Button and Start Menu, which gives users access to 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 9x/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.

Windows also comes with features to help the disabled through its accessibility options. Under Windows XP, these features include the Narrator, Magnifier and contrast display mode.

Popularity

Thought to be installed on over 90% of personal computers (currently decreasing due to switching to Mac OS X, Linux, and other x86 OSes), 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, due to the sunset of MS-DOS and more compatibility on other platforms such as the Apple Macintosh and Linux, it 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 does not license Mac OS X and Sun did not license Solaris to anyone before it was open-sourced). Before, companies who wanted to be in the computer business had to create their own operating system (such as the Amiga) or use an 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. Further, a growing part of the computer market 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

Security has been a major weakness of Windows for many years. Due to the widespread usage of Windows on desktops, many Black Hat hackers (also known as crackers) have targeted Windows rather than the lesser used operating systems such as Linux, Unix, Mac OS X, and FreeBSD. Additionally 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 overflows), Windows is a continous target of worms and virus writers. 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 claim it gets more attacks because poor engineering design makes it such an easy target. Microsoft publicly admitted their ongoing security problems shortly after the turn of the century and now claims to regard security as their number one priority. As a result, Service Pack 2 for Windows XP greatly increases the security.

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.

A study conducted by Kevin Mitnick and marketing communications firm, Avantgarde, found that an unprotected and 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.

Emulation software

Emulation allows the use of some Windows applications without using Microsoft Windows.

• WINE – an almost complete free software / open source software implementation of the Windows API, allowing one to run some Windows applications on x86 Unix-based platforms, including Linux.
• Cedega (formerly known as WineX) – TransGaming Technologies' proprietary fork of WINE, which is designed specifically for running games written for Microsoft Windows under Linux.
• Mono and Shared source CLI – alternatives to the Microsoft .NET framework.
• ReactOS – open source operating system, aimed to be compatible with Windows NT apps and drivers, although still very much in its infancy at the moment.
• Freedows and Alliance OS – a very ambitious project, and a subsequent spinoff, that tried to clone Windows but withered away.
• Project David – ambitious and controversial project to fully emulate Windows programs to run on other OSs.
• Codeweavers CrossOver Office product, also to fully emulate Windows programs to run on other OSs.
• Captive NTFS – a software "wrapper" for fuller, more-compatible open-source implementations of the Windows NTFS file system.
• E/OS – goal to make it possible to run any program designed for any operating system without the need to actually install any other operating system.

See also

• Architecture of Windows 2000
• Blue Screen of Death
• Comparison of operating systems
• Hardware
  • Hardware abstraction layer
  • Hardware description language
  • KMixer
  • VGASAVE
  • Windows Driver Model
  • WinHEC
• History of Microsoft Windows
• List of operating systems
• Microsoft Anti-Virus for Windows
• Microsoft Visual Studio
• Volume Shadow Copy Service
• Windows Blackcomb – next generation server platform
• Windows Explorer
• Windows Genuine Advantage
• Windows Media
• Windows vs. Linux

External links

• Microsoft's Official Windows Website
• Official Promotional Website (Windows.com)
• Windows history time line from Microsoft
• Windows history – a Windows history time line graph by Éric Lévénez
• How to run multiple versions of Windows on one PC
• GUIdebook: Windows Gallery – a website dedicated to preserving and showcasing graphical user interfaces
• Paul Thurrott's SuperSite for Windows – an exhaustive evaluation of Microsoft's products and technologies
• The Windows Documentation Project (wiki)
• "Time to Live on the Network" – a security study by Kevin Mitnick and AvantGarde (PDF)
• AOL/National Cyber Security Alliance Online Safety Study (October 2004) (PDF)
• Securing Microsoft Windows (for Home and Small Business Users)
• Windows tips (security, stability, etc.) (wiki)
• Download.com – application programs for download, for Windows operating systems
• Symantec Anti-Virus Research Center – excellent informational security resource, and Symantec are makers of Norton Anti-Virus (3rd party software sold separately)
• dotwhat? - File Extension Listing – a huge listing of file extensions and the programs that use them
• Windows – tips and tricks for Windows 98, ME, NT, 2000 and XP
• Techzonez - Microsoft Expert Zone Member (provides technical support for windows related issues)
• Interface Hall of Shame – an analysis of user interfaces with a focus on Windows
• Windows XP: rough around the edges – an UI review of Windows XP
• Frank Mahler's Interface Hall Of Shame
• Windows 20th Birthday

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