Microsoft Windows is a series of
graphical interface operating systems developed, marketed, and sold by
Microsoft.
Microsoft introduced an
operating environment named
Windows on November 20, 1985 as an add-on to
MS-DOS in response to the growing interest in
graphical user interfaces (GUIs).
[2] Microsoft Windows came to
dominate the world's
personal computer market with
over 90% market share, overtaking
Mac OS, which had been introduced in 1984.
The most recent client version of Windows is
Windows 7; the most recent
server version is
Windows Server 2012; the most recent
mobile version is
Windows Phone 7.5.
Versions
The term
Windows collectively describes any or all of several generations of
Microsoft operating system products. These products are generally categorized as follows:
The classic Windows logo, used from 1992 until the release of
Windows XP in 2001
Early versions
Windows 1.0, the first version, released in 1985
The history of Windows dates back to September 1981, when Chase
Bishop, a computer scientist, designed the first model of an electronic
device and project "Interface Manager" was started. It was announced in
November 1983 (after the
Apple Lisa, but before the
Macintosh) under the name "Windows", but
Windows 1.0 was not released until November 1985.
[3] The
shell of Windows 1.0 was a program known as the
MS-DOS Executive. Other supplied programs were
Calculator,
Calendar,
Cardfile,
Clipboard viewer, Clock,
Control Panel,
Notepad,
Paint,
Reversi,
Terminal, and
Write. Windows 1.0 did not allow overlapping windows. Instead all windows were
tiled. Only dialog boxes could appear over other windows.
Windows 2.0 was released in October 1987 and featured several improvements to the user interface and memory management.
[3] Windows 2.0 allowed application windows to overlap each other and also introduced more sophisticated
keyboard shortcuts. It could also make use of
expanded memory.
Windows 2.1 was released in two different versions:
Windows/386 employed the
386 virtual 8086 mode to multitask several DOS programs, and the paged memory model to emulate expanded memory using available
extended memory.
Windows/286 (which, despite its name, would run on the 8086) still ran in
real mode, but could make use of the
high memory area.
In addition to full Windows-packages, there were runtime only
versions that shipped with early Windows software from third parties and
made it possible to run their Windows software under MS-DOS and without
the full Windows feature set.
The early versions of Windows were often thought of as simply graphical user interfaces, mostly because they ran on top of
MS-DOS and used it for
file system services.
[4]
However, even the earliest 16-bit Windows versions already assumed many
typical operating system functions; notably, having their own
executable file format and providing their own
device drivers (timer, graphics, printer, mouse, keyboard and sound) for applications. Unlike
MS-DOS, Windows allowed users to execute multiple graphical applications at the same time, through
cooperative multitasking.
Windows implemented an elaborate, segment-based, software virtual
memory scheme, which allowed it to run applications larger than
available memory: code segments and
resources
were swapped in and thrown away when memory became scarce, and data
segments moved in memory when a given application had relinquished
processor control.
Windows 3.0 and 3.1
Windows 3.0, released in 1990
Windows 3.0 (1990) and
Windows 3.1 (1992) improved the design, mostly because of
virtual memory and loadable virtual device drivers (
VxDs) that allowed them to share arbitrary devices between multitasked DOS windows.
[citation needed] Also, Windows applications could now run in
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.
Windows 95, 98, and Me
Windows 95 was released in August 1995, featuring a new
object oriented user interface, support for
long file names of up to 255 characters, and the ability to automatically detect and configure installed hardware (
plug and play).
It could natively run 32-bit applications, and featured several
technological improvements that increased its stability over Windows
3.1. There were several OEM Service Releases (OSR) of Windows 95, each
of which was roughly equivalent to a
service pack.
Microsoft's next release was
Windows 98 in June 1998. Microsoft released a second version of Windows 98 in May 1999, named
Windows 98 Second Edition (often shortened to Windows 98 SE).
In February 2000,
Windows 2000 (in the NT family) was released, followed by
Windows Me in September 2000 (
Me standing for
Millennium Edition).
Windows Me updated the core from Windows 98, but adopted some aspects
of Windows 2000 and removed the "boot in DOS mode" option. It also added
a new feature called
System Restore, allowing the user to set the computer's settings back to an earlier date.
Windows Millennium Edition is often confused with
Windows 2000 (because of its name), and has been said to be one of the worst operating systems Microsoft ever released.
[5]
Windows NT family
The Windows logo used from 2001 to 2006, for the
Windows XP operating system.
The NT family of Windows systems was fashioned and marketed for higher reliability business use. The first release was
NT 3.1 (1993), numbered "3.1" to match the consumer Windows version, which was followed by
NT 3.5 (1994),
NT 3.51 (1995),
NT 4.0 (1996), and
Windows 2000, which is the last NT-based Windows release that does not include Microsoft
Product Activation.
Windows NT 4.0 was the first in this line to implement the "Windows 95"
user interface (and the first to include Windows 95's built-in 32-bit
runtimes).
Microsoft then moved to combine their consumer and business operating systems with
Windows XP that was released on October 25, 2001. It came both in home and professional versions (and later niche market versions for
tablet PCs and
media centers); they also diverged release schedules for server operating systems.
Windows Server 2003, released a year and a half after Windows XP, brought
Windows Server up to date with Windows XP. After a lengthy
development process,
Windows Vista was released on November 30, 2006 for volume licensing and January 30, 2007 for consumers. Its server counterpart,
Windows Server 2008 was released in early 2008. On July 22, 2009,
Windows 7 and
Windows Server 2008 R2 were released as RTM (release to manufacturing) while the former was released to the public 3 months later on October 22, 2009.
64-bit operating systems
Windows NT included support for several different platforms before the
x86-based
personal computer became dominant in the professional world. Versions of NT from 3.1 to 4.0 variously supported
PowerPC,
DEC Alpha and
MIPS R4000, some of which were 64-bit processors, although the operating system treated them as 32-bit processors.
With the introduction of the
Intel Itanium architecture (also known as IA-64), Microsoft released new versions of Windows to support it. Itanium versions of
Windows XP and
Windows Server 2003 were released at the same time as their mainstream x86 (32-bit) counterparts. On April 25, 2005, Microsoft released
Windows XP Professional x64 Edition and Windows Server 2003 x64 Editions to support the
x86-64 (or
x64 in Microsoft terminology) architecture. Microsoft dropped support for the Itanium version of Windows XP in 2005.
Windows Vista
was the first end-user version of Windows that Microsoft released
simultaneously in x86 and x64 editions. Windows Vista does not support
the Itanium architecture. The modern 64-bit Windows family comprises
AMD64/Intel64 versions of Windows 7 and
Windows Server 2008, in both Itanium and x64 editions. Windows Server 2008 R2 drops the 32-bit version, although
Windows 7 does not.
Windows CE
The latest current version of Windows CE,
Windows Embedded Compact 7, displaying a possible UI for what the media player can look like.
Windows CE (officially known as
Windows Embedded Compact), is
an edition of Windows that runs on minimalistic computers, like
satellite navigation systems and some mobile phones. Windows Embedded
Compact is based on its own dedicated kernel, dubbed Windows CE kernel.
Microsoft licenses Windows CE to
OEMs
and device makers. The OEMs and device makers can modify and create
their own user interfaces and experiences, while Windows CE provides the
technical foundation to do so.
Windows CE was used in the
Dreamcast along with Sega's own proprietary OS for the console. Windows CE is the core from which
Windows Mobile is derived. Microsoft's latest
mobile OS,
Windows Phone, is based on components from both
Windows CE 6.0 R3 and the current
Windows CE 7.0.
Windows Embedded Compact is not to be confused with
Windows XP Embedded or
Windows NT 4.0 Embedded, modular editions of Windows based on Windows NT kernel.
Windows 8
The Start Screen of Windows 8 RTM (Build 9200).
Windows 8,
the successor to Windows 7, has finished its development, and will be
released to the market on 26 October 2012. Windows 8 has been designed
to be used on both tablets and the conventional PC. The
Microsoft Surface
tablet is to be released alongside Windows 8, as a competitor to the
Apple iPad and Samsung Galaxy Tab. It has been announced by Microsoft
that Windows Surface will be available in two editions - one for the
typical end user, and a Professional edition aimed at designers and
other work-based users. Windows 8 was released to manufacturing on 1
August 2012, with a build of 6.2.9200.
History
The first version of Microsoft Windows,
version 1.0,
released in November 1985, lacked a degree of functionality, achieved
little popularity and was to compete with Apple's own operating system.
Windows 1.0 is not a complete operating system; rather, it extends
MS-DOS. Microsoft Windows
version 2.0
was released in November 1987 and was slightly more popular than its
predecessor. Windows 2.03 (release date January 1988) had changed the OS
from tiled windows to overlapping windows. The result of this change
led to Apple Computer filing a suit against Microsoft alleging
infringement on Apple's copyrights.
[6][7]
Microsoft Windows
version 3.0,
released in 1990, was the first Microsoft Windows version to achieve
broad commercial success, selling 2 million copies in the first six
months.
[8][9]
It featured improvements to the user interface and to multitasking
capabilities. It received a facelift in Windows 3.1, made generally
available on March 1, 1992. In August 1993, a special version with
integrated peer-to-peer networking was released with version number
3.11. It was sold parallelly with the basic version under name Windows
for Workgroups. Windows 3.1 support ended on December 31, 2001.
[10]
In July 1993, Microsoft released
Windows NT based on a new kernel.
Windows NT 3.1 was the first release of Windows NT. NT was considered to be the professional OS and was the first Windows version to utilize
preemptive multitasking.
[citation needed] Windows NT would later be retooled to also function as a home operating system, with Windows XP.
On August 24, 1995, Microsoft released
Windows 95,
a new, and major, consumer version that made further changes to the
user interface, and also used preemptive multitasking. Windows 95 was
designed to replace not only Windows 3.1, but also Windows for
Workgroups, and MS-DOS. It was also the first Windows operating system
to include
object oriented
document management and use Plug and Play capabilities. The changes
Windows 95 brought to the desktop were revolutionary, as opposed to
evolutionary, such as those in Windows 98 and Windows Me. Mainstream
support for Windows 95 ended on December 31, 2000 and extended support
for Windows 95 ended on December 31, 2001.
[11]
Next in the consumer line was Microsoft
Windows 98
released on June 25, 1998. It was followed with the release of Windows
98 Second Edition (Windows 98 SE) in 1999. Mainstream support for
Windows 98 ended on June 30, 2002 and extended support for Windows 98
ended on July 11, 2006.
[12]
As part of its "professional" line, Microsoft released
Windows 2000
in February 2000. During 2004 part of the Source Code for Windows 2000
was leaked onto the Internet. This was bad for Microsoft as the same
kernel used in Windows 2000 was used in Windows XP. The consumer version
following Windows 98 was
Windows Me
(Windows Millennium Edition). Released in September 2000, Windows Me
implemented a number of new technologies for Microsoft: most notably
publicized was "
Universal Plug and Play". Windows Me was heavily criticized due to slowness,
freezes and hardware problems.
In October 2001, Microsoft released
Windows XP, a version built on the Windows NT
kernel
that also retained the consumer-oriented usability of Windows 95 and
its successors. This new version was widely praised in computer
magazines.
[13]
It shipped in two distinct editions, "Home" and "Professional", the
former lacking many of the superior security and networking features of
the Professional edition. Additionally, the first "Media Center" edition
was released in 2002,
[14]
with an emphasis on support for DVD and TV functionality including
program recording and a remote control. Mainstream support for Windows
XP ended on April 14, 2009. Extended support will continue until April
8, 2014.
[15]
In April 2003,
Windows Server 2003
was introduced, replacing the Windows 2000 line of server products with
a number of new features and a strong focus on security; this was
followed in December 2005 by Windows Server 2003 R2.
On January 30, 2007, Microsoft released
Windows Vista. It contains a number of
new features, from a redesigned shell and user interface to significant
technical changes, with a particular focus on
security features. It is available in a number of
different editions, and has been subject to
some criticism.
On October 22, 2009, Microsoft released
Windows 7.
Unlike its predecessor, Windows Vista, which introduced a large number
of new features, Windows 7 was intended to be a more focused,
incremental upgrade to the Windows line, with the goal of being
compatible with applications and hardware which Windows Vista was not at
the time.
[16] Windows 7 has
multi-touch support, a redesigned
Windows shell with a new
taskbar, referred to as the Superbar, a home networking system called HomeGroup,
[17] and performance improvements.
On February 29, 2012, Microsoft released Windows 8 Consumer Preview,
the beta version of Windows 8, build 8250. For the first time since
Windows 95, the Start button is no longer available on the taskbar. It
has been replaced with the Start screen and can be triggered by clicking
the bottom-left corner of the screen and by clicking Start in the Charm
or by depressing the
Windows Key
on the keyboard. Windows president Steven Sinofsky said more than
100,000 changes had been made since the developer version went public.
In the first day of its release, Windows 8 Consumer Preview was
downloaded over one million times. Microsoft released the Windows 8
Release Preview, Build 8400 on June 1, 2012. Like the Developer Preview,
the Consumer Preview and the Release Preview are both set to expire on
January 15, 2013.
Timeline of releases
[show]Timeline of releases |
Usage share
Source |
Net Market Share[23] |
W3Counter[24] |
Global Stats[25] |
Date |
September 2012 |
September 2012 |
September 2012 |
All versions |
91.73% |
76.6% |
87.42% |
Windows 7 |
44.04% |
44.79% |
52.2% |
Windows XP |
41.23% |
25.15% |
27.64% |
Windows Vista |
6.05% |
6.36% |
7.58% |
Windows 8 |
0.3% |
0.3% |
— |
Windows 2000 |
0.07% |
— |
— |
Windows NT 4.0 |
0.03% |
— |
— |
Windows 98 |
0.01% |
— |
— |
Security
Consumer versions of Windows were 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.
[26]
However, Windows NT and its successors are designed for security
(including on a network) and multi-user PCs, but were not initially
designed with Internet security in mind as much, since, when it was
first developed in the early 1990s, Internet use was less prevalent.
[27]
These design issues combined with programming errors (e.g.
buffer overflows) and the popularity of Windows means that it is a frequent target of
computer worm 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.
[28] In 2005,
Kaspersky Lab found around 11,000 malicious programs—viruses, Trojans, back-doors, and exploits written for Windows.
[29]
Microsoft releases security patches through its
Windows Update service approximately once a month (usually the
second Tuesday of the month), although critical updates are made available at shorter intervals when necessary.
[30]
In versions of Windows after and including Windows 2000 SP3 and Windows
XP, updates can be automatically downloaded and installed if the user
selects to do so. As a result, Service Pack 2 for Windows XP, as well as
Service Pack 1 for Windows Server 2003, were installed by users more
quickly than it otherwise might have been.
[31]
While the
Windows 9x series offered the option of having profiles for multiple users, they had no concept of
access privileges, and did not allow concurrent access; and so were not true
multi-user operating systems. In addition, they implemented only partial
memory protection. They were accordingly widely criticised for lack of security.
The
Windows NT
series of operating systems, by contrast, are true multi-user, and
implement absolute memory protection. However, a lot of the advantages
of being a true multi-user operating system were nullified by the fact
that, prior to Windows Vista, the first user account created during the
setup process was an
administrator account, which was also the default for new accounts. Though
Windows XP
did have limited accounts, the majority of home users did not change to
an account type with fewer rights – partially due to the number of
programs which unnecessarily required administrator rights – and so most
home users ran as administrator all the time.
Windows Vista changes this
[32] by introducing a privilege elevation system called
User Account Control. When logging in as a standard user, a logon session is created and a
token
containing only the most basic privileges is assigned. In this way, the
new logon session is incapable of making changes that would affect the
entire system. When logging in as a user in the Administrators group,
two separate tokens are assigned. The first token contains all
privileges typically awarded to an administrator, and the second is a
restricted token similar to what a standard user would receive. User
applications, including the
Windows Shell,
are then started with the restricted token, resulting in a reduced
privilege environment even under an Administrator account. When an
application requests higher privileges or "Run as administrator" is
clicked, UAC will prompt for confirmation and, if consent is given
(including administrator credentials if the account requesting the
elevation is not a member of the administrators group), start the
process using the unrestricted token.
[33]
File permissions
All Windows versions from Windows NT 3 have been based on a file
system permission system referred to as AGLP (Accounts, Global, Local,
Permissions)
AGDLP
which in essence where file permissions are applied to the file/folder
in the form of a 'local group' which then has other 'global groups' as
members. These global groups then hold other groups or users depending
on different Windows versions used. This system varies from other vendor
products such as
Linux and
NetWare
due to the 'static' allocation of permission being applied directory to
the file or folder. However using this process of AGLP/AGDLP/AGUDLP
allows a small number of static permissions to be applied and allows for
easy changes to the account groups without reapplying the file
permissions on the files and folders.
Windows Defender
On January 6, 2005, Microsoft released a
Beta version of Microsoft AntiSpyware, based upon the previously released
Giant AntiSpyware. On February 14, 2006, Microsoft AntiSpyware became
Windows Defender
with the release of Beta 2. Windows Defender is a freeware program
designed to protect against spyware and other unwanted software. Windows
XP and Windows Server 2003 users who have
genuine
copies of Microsoft Windows can freely download the program from
Microsoft's web site, and Windows Defender ships as part of Windows
Vista and 7.
[34]
In Windows 8, Windows Defender and Microsoft Security Essentials have
been combined into a single program, named Windows Defender. It is based
on Microsoft Security Essentials borrowing its features and user
interface. Although it is enabled by default, it can be turned off to
use another anti-virus solution.
[35]
Third-party analysis
In an article based on a report by Symantec,
[36]
internetnews.com has described Microsoft Windows as having the "fewest
number of patches and the shortest average patch development time of the
five operating systems it monitored in the last six months of 2006."
[37]
A study conducted by
Kevin Mitnick
and marketing communications firm Avantgarde in 2004 found that an
unprotected and unpatched Windows XP system with Service Pack 1 lasted
only 4 minutes on the Internet before it was compromised, and an
unprotected and also unpatched Windows Server 2003 system was
compromised after being connected to the internet for 8 hours.
[38]
This study does not apply to Windows XP systems running the Service
Pack 2 update (released in late 2004), which vastly improved the
security of Windows XP.
[citation needed] The computer that was running Windows XP Service Pack 2 was not compromised. 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.
[citation needed]
Much documentation is available describing how to increase the security
of Microsoft Windows products. Typical suggestions include deploying
Microsoft Windows behind a hardware or software
firewall, running
anti-virus and
anti-spyware software, and installing patches as they become available through Windows Update.
[39]
Emulation software
Emulation allows the use of some Windows applications without using Microsoft Windows. These include:
- Wine – a free and open source software implementation of the Windows API, allowing one to run many Windows applications on x86-based platforms, including Linux and Mac OS X. Wine developers refer to it as a "compatibility layer";[40] and make use of Windows-style APIs to emulate the Windows environment.
- CrossOver –
A Wine package with licensed fonts. Its developers are regular
contributors to Wine, and focus on Wine running officially supported
applications.
- Cedega – TransGaming Technologies' proprietary fork of Wine, designed specifically for running games written for Microsoft Windows under Linux. A version of Cedega known as Cider
is used by some video game publishers to allow Windows games to run on
Mac OS X. Since Wine was licensed under the LGPL, Cedega has been unable
to port the improvements made to Wine to their proprietary codebase.
Cedega ceased its service in February 2011.
- Darwine – A bundling of Wine to the PowerPC Macs running OS X by running Wine on top of QEMU. Intel Macs use the same Wine as other *NIX x86 systems.
- ReactOS –
An open-source OS that is intended to run the same software as Windows,
originally designed to simulate Windows NT 4.0, now aiming at Windows
XP and Vista/7 compatibility. It has been in the development stage since 1996.