Windows 98 (codenamed Memphis) is a graphical operating system by Microsoft. It is the second major release in the Windows 9x line of operating systems. It was released to manufacturing on May 15, 1998 and to retail on June 25, 1998. Windows 98 is the successor to Windows 95. Like its predecessor, it is a hybrid 16-bit/32-bit monolithic product with an MS-DOS based boot stage. Windows 98 was succeeded by Windows 98 Second Edition on May 5, 1999, then by Windows ME (Millennium Edition) on September 14, 2000. Microsoft ended support for Windows 98 on July 11, 2006.
Windows 98 includes Internet Explorer 4.01. Besides Internet Explorer, many other Internet companion applications are included such as Outlook Express, Windows Address Book, FrontPage Express, Microsoft Chat, Personal Web Server and a Web Publishing Wizard, NetMeeting and NetShow Player (in the original release of Windows 98) which was replaced by Windows Media Player 6.2 in Windows 98 Second Edition.
The Windows 98 shell includes all of the enhancements from Windows Desktop Update, an Internet Explorer 4 component, such as the Quick Launch toolbar, deskbands, Active Desktop, Channels, ability to minimize foreground windows by clicking their button on the taskbar, single click launching, Back and Forward navigation buttons, favorites, and address bar in Windows Explorer, image thumbnails, folder infotips and web view in folders, and folder customization through HTML-based templates. Dialog boxes now show up in the Alt-Tab sequence.
Windows 98 also integrates shell enhancements, themes and other features from Microsoft Plus! for Windows 95 such as DriveSpace 3, Compression Agent, Dial-Up Networking Server, Dial-Up Scripting Tool and Task Scheduler. 3D Pinball is included on the CD-ROM but not installed by default. Windows 98 had its own separately purchasable Plus! pack called Plus! 98.
Title bars of windows and dialog boxes support two-color gradients. Windows 98 menus and tooltips support slide animation. Windows Explorer in Windows 98, like Windows 95, converts all uppercase filenames to Sentence case for readability purposes; however, it also provides an option Allow all uppercase names to display them in their original case. Windows Explorer includes support for compressed CAB files. The Quick Res and Telephony Location Manager Windows 95 PowerToys are integrated.
Windows 98 was the first operating system to use the Windows Driver Model (WDM). This fact was not well publicized when Windows 98 was released, and most hardware producers continued to develop drivers for the older VxD driver standard, which Windows 98 also supported. The WDM standard only achieved widespread adoption years later, mostly through Windows 2000 and Windows XP, as they are not compatible with the older VxD standard. Windows Driver Model was introduced largely so that developers would write source compatible drivers for all future versions of Windows. Device driver access in WDM is actually implemented through a VxD device driver, NTKERN.VXD which implements several Windows NT-specific kernel support functions. NTKERN creates IRPs and sends them to WDM drivers.
Support for WDM audio enables digital mixing, routing and processing of simultaneous audio streams and kernel streaming with high quality sample rate conversion on Windows 98. WDM Audio allows for software emulation of legacy hardware to support MS-DOS games, DirectSound support and MIDI wavetable synthesis. The Windows 95 11-device limitation for MIDI devices is eliminated. A Microsoft GS Wavetable Synthesizer licensed from Roland shipped with Windows 98 for WDM audio drivers. Windows 98 supports digital playback of audio CDs, and the Second Edition improves WDM audio support by adding DirectSound hardware mixing and DirectSound 3D hardware abstraction, DirectMusic kernel support, KMixer sample-rate conversion (SRC) for capture streams and multichannel audio support. All audio is sampled by the Kernel Mixer to a fixed sampling rate which may result in some audio getting upsampled or downsampled and having a high latency, except when using Kernel Streaming or third party audio paths like ASIO which allow unmixed audio streams and lower latency. Windows 98 also includes a WDM streaming class driver (Stream.sys) to address real time multimedia data stream processing requirements and a WDM kernel-mode video transport for enhanced video playback and capture.
Windows Driver Model also includes Broadcast Driver Architecture, the backbone for TV technologies support in Windows. WebTV for Windows utilized BDA to allow viewing television on the computer if a compatible TV tuner card is installed. TV listings could be updated from the Internet and WaveTop Data Broadcasting allowed extra data about broadcasts to be received via regular television signals using an antenna or cable, by embedding data streams into the vertical blanking interval (VBI) portion of existing broadcast television signals.
USB
Windows 98 had more robust USB support (e.g. support for USB composite devices) than Windows 95 which only had support in OEM versions (OSR2.1 or later). Windows 98 supports USB hubs, USB scanners and imaging class devices. Windows 98 also introduces built-in support for some USB Human Interface Device class (USB HID) and PID class devices such as USB mice, keyboards, force feedback joysticks etc. including additional keyboard functions through a certain number of Consumer Page HID controls.
USB audio device class support is present from Windows 98 SE onward. Windows 98 Second Edition improved WDM support in general for all devices, and it introduced support for WDM for modems (and therefore USB modems and virtual COM ports). Microsoft driver support for both USB printers, and for USB mass-storage device class is not available for Windows 98; support for both was introduced in Windows 2000; however generic third party free drivers are available today for USB MSC devices.
ACPI
Windows 98 introduced ACPI 1.0 support which enabled Standby (ACPI S3) and Hibernate (ACPI S4) states. However, hibernation support was extremely limited, and vendor-specific. Hibernation was only available if compatible (PnP) hardware and BIOS are present, and the hardware manufacturer or OEM supplied compatible WDM drivers, non-VxD drivers. However, there are hibernation issues with the FAT32 file system, making hibernation problematic and unreliable.
Other device support improvements
Windows 98, in general, provides improved—and a broader range of—support for IDE and SCSI drives and drive controllers, floppy drive controllers and all other classes of hardware than Windows 95. There is integrated Accelerated Graphics Port (AGP) support (although the USB Supplement to Windows 95 OSR2 and later releases of Windows 95 did have AGP support). Windows 98 has built-in DVD support and UDF 1.02 read support. The Still imaging architecture (STI) with TWAIN support was introduced for scanners and cameras and Image Color Management 2.0 for devices to perform color space transformations. Multiple monitor support allows using up to 8 multiple monitors and/or multiple graphics adapters on a single PC. Windows 98 shipped with DirectX 5.2 which notably included DirectShow. Windows 98 Second Edition shipped with DirectX 6.1.
Unofficial Windows 98 Second Edition Service Pack 3.66
An unofficial service pack that continued some upgrades of Windows 98 SE was made by a group of enthusiasts it can be downloaded here: Unofficial Windows 98 Second Edition Service Pack 3.66