Windows 95 (codenamed Chicago) is a consumer-oriented graphical user interface-based operating system developed by Microsoft. It was released on August 24, 1995, and was a significant progression from the company's previous Windows products. During development, it was referred to as Windows 4.0 or by the internal codename Chicago.
Windows 95 integrated Microsoft's formerly separate MS-DOS and Windows products. It featured significant improvements over its predecessor, Windows 3.1, most notably in the graphical user interface (GUI) and in its relatively simplified "plug-n-play" features. There were also major changes made at lower levels of the operating system, such as moving from a mainly 16-bit architecture to a pre-emptively multitasked 32-bit architecture.
Accompanied by an extensive marketing campaign, Windows 95 was a major success in the marketplace at launch and shortly became the most popular desktop operating system. It also introduced numerous functions and features that were featured in later Windows versions, such as the taskbar, the 'Start' button, and the way the user navigates. It was also suggested that Windows 95 had an effect of driving other major players (including OS/2) out of business, something which would later be used in court against Microsoft.
Some three years after its introduction, Windows 95 was succeeded by Windows 98. Support for Windows 95 ended on December 31, 2001.
The initial design and planning of Windows 95 can be traced back to around March 1992, just after the release of Windows 3.1. At this time, Windows for Workgroups 3.11 and Windows NT 3.1 were still in development and Microsoft's plan for the future was focused on Cairo. Cairo would be Microsoft's next-generation operating system based on Windows NT and featuring a new user interface and an object-based file system, but it was not planned to be shipped before 1994 (Cairo would eventually partially ship in July 1996 in the form of Windows NT 4.0, but without the object-based file system, which would later evolve into WinFS).
Simultaneously with Windows 3.1's release, IBM started shipping OS/2 2.0. Microsoft realized they were in need of an updated version of Windows that could support 32-bit applications and preemptive multitasking, but could still run on low-end hardware (Windows NT did not). So the development of Windows "Chicago" was started and, as it was planned for a late 1993 release, became known as Windows 93. Initially, the decision was made not to include a new user interface, as this was planned for Cairo, and only focus on making installation, configuration, and networking easier. Windows 93 would ship together with MS-DOS 7.0, offering a more integrated experience to the user and making it pointless for other companies to create DOS clones. MS-DOS 7.0 was in development at that time under the code name "Jaguar" and could optionally run on top of a Windows 3.1-based 32-bit protected mode kernel called "Cougar" in order to better compete with DR-DOS. The first version of Chicago's feature specification was finished on September 30, 1992. Cougar was to become Chicago's kernel.
Prior to the official release, the American public was given a chance to preview Windows 95 in the Windows 95 Preview Program. For US$19.95, users were sent a set of 3.5-inch floppy diskettes that would install Windows 95 either as an upgrade to Windows 3.1x or as a fresh install on a clean computer. Users who bought into the program were also given a free preview of The Microsoft Network (MSN), the online service that Microsoft launched with Windows 95. During the preview period Microsoft established various electronic distribution points for promotional and technical documentation on Chicago including a detailed document for media reviewers describing the new system highlights. The preview versions expired in November 1995, after which the user would have to purchase their own copy of the final version of Windows 95. Some releases were made that haven't been leaked, such as Chicago 30.
Windows 95 was released with great fanfare, including a commercial featuring the Rolling Stones' 1981 single "Start Me Up" (a reference to the Start button). It was widely reported that Microsoft paid the Rolling Stones between US$8 and US$14 million for the use of the song in the 95 advertising campaign. According to sources at Microsoft, however, this was just a rumor spread by the band to increase their market value, and Microsoft actually paid a fraction of that amount. A 30-minute promotional video, labeled a "cyber sitcom", featuring Jennifer Aniston and Matthew Perry, was also released to showcase the features of Windows 95. Microsoft's US$300 million advertising campaign featured stories of people waiting in line outside stores to get a copy.
In the UK, the largest computer chain PC World received a large number of oversized Windows 95 boxes, posters and point of sale material, and many branches opened at midnight to sell the first copies of the product. In London, Microsoft gave free newspapers to people.
In the United States, the Empire State Building in New York City was lit to match the colors of the Windows logo. In Canada, a 328 ft (100 m) banner was hung from the top of the CN Tower in Toronto. Copies of The Times were available for free in the United Kingdom where Microsoft paid for 1.5 million issues (twice the daily circulation at the time).
The release included a number of "Fun Stuff" items on the CD, including music videos of Edie Brickell's "Good Times" and Weezer's "Buddy Holly". On the CD version a computer game called Hover! was also included.