Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. The second operating system in the 9x line, it is the successor to Windows 95, and was released to manufacturing on May 15, 1998, and generally to retail on June 25, 1998. Like its predecessor, it is a hybrid 16-bit and 32-bit monolithic product with the boot stage based on MS-DOS. Windows 98 is a web-integrated operating system that bears numerous similarities to its predecessor. Most of its improvements were cosmetic or designed to improve the user experience, but there were also a handful of features introduced to enhance system functionality and capabilities, including improved USB support and accessibility, as well as support for hardware advancements such as DVD players. Windows 98 was the first edition of Windows to adopt the Windows Driver Model, and introduced features that would become standard in future generations of Windows, such as Disk Cleanup, Windows Update, multi-monitor support, and Internet Connection Sharing. Microsoft had marketed Windows 98 as a "tune-up" to Windows 95, rather than an entirely improved next generation of Windows. Upon release, it was generally well-received for its web-integrated interface and ease of use, as well as its addressing of issues present in Windows 95, although some pointed out that it was not significantly more stable than its predecessor. Windows 98 sold an estimated 58 million licenses and saw one major update, known as Windows 98 Second Edition (SE), released on May 5, 1999. After the release of its successor, Windows Me in 2000, mainstream support for Windows 98 and 98 SE ended on June 30, 2002, followed by extended support on July 11, 2006. Development Following the success of Windows 95, the development of Windows 98 began, initially under the development codename "Memphis." The first test version, Windows Memphis Developer Release, was released in January 1997. Memphis first entered beta as Windows Memphis Beta 1, released on June 30, 1997. It was followed by Windows 98 Beta 2, which dropped the Memphis name and was released in July. Microsoft had planned a full release of Windows 98 for the first quarter of 1998, along with a Windows 98 upgrade pack for Windows 95, but it also had a similar upgrade for Windows 3.x operating systems planned for the second quarter. Stacey Breyfogle, a product manager for Microsoft, explained that