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Additional Requirements for Windows 98

Last Updated: 10/10/2016

In Microsoft Windows 98, a bug in the system graph builder prevents a KSCATEGORY_AUDIO_DEVICE wave-data path from operating correctly unless it contains at least one node. Because PCM pins are either hardware mixing pins (with SUM, volume, and SRC nodes, for example; see KSNODETYPE_SUM, KSNODETYPE_VOLUME, and KSNODETYPE_SRC) or have KMixer (and its nodes) inserted above them, this problem affects non-PCM pins only. In order for your driver to work on Windows 98 SE + hotfix, make sure that the data path through a non-PCM pin always has at least one node. When passing AC-3 over S/PDIF, for example, you can add a KSNODETYPE_SPDIF_INTERFACE node that implements a property to manipulate the serial copy management system (SCMS) bits in the S/PDIF digital output stream.

The earliest hot-fix package for Windows 98 SE that contains the fix to enable AC-3 playback over S/PDIF is the following:

Hot-Fix NumberExecutable FileRelease Date

WinSE 9724



All later hot-fix packages for Windows 98 SE also contain this fix.

This hot-fix package installs updated versions of the following audio system files:

  • Kmixer.sys

  • Portcls.sys

  • Sbemul.sys

  • Sysaudio.sys

  • Usbaudio.sys

  • Wdmaud.sys

  • Wdmaud.drv

The IPortClsVersion interface is not available in this hotfix, which means that this interface cannot be used to detect the presence of the hotfix.

The best way to determine whether a hotfix that contains the WavePci fixes is present is as follows:

  • Verify that the operating system is Windows 98 Second Edition.

  • Check the file version and/or date of Portcls.sys.

The WavePci fixes are present in the following the file version and date of Portcls.sys (or in any more recent version):

  • File Version: 4.10.2223

  • Date Created: 3/21/2000 8:34:03 PM

Another technique is to look in the registry to determine whether a particular hotfix has been installed. For example, you can try to access the following registry key to see whether the first hot-fix package for Windows 98 SE is installed:


The key exists only if the first hot-fix package is installed. The drawback to this approach is that it does not tell you whether a later hot-fix package, which also includes the WavePci fixes, is installed.

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