Version 79 (modified by David Azarewicz, 7 years ago) (diff)


Uniaud for OS/2 & eCS

This is the development home for uniaud, the Universal Audio Driver for eCS and OS/2. The Uniaud project consists of 2 separate drivers, Uniaud16.sys and Uniaud32.sys.


Uniaud32.sys is the actual audio driver that connects to the hardware and makes it work. It consists of a modified ALSA core and some OS/2 specific pieces which make it load and run on an OS/2 system. Different major versions of Uniaud32 are based on different versions of ALSA. For example, Uniaud32 versions 1.9.x are based on ALSA 1.0.21, and Uniaud32 versions 2.1.x are based on ALSA 1.0.23.


Uniaud16.sys is the interface between MMOS2 and Uniaud32.sys. Uniaud16 does not talk to the audio hardware. It is just an interface translator, buffer manager, and may do some resampling. Uniaud16.sys has its own version number. Do not confuse Uniaud16's version number with Uniaud32's version number.

Downloading Binary Distributions

The "Complete Install Package" is used to install Uniaud on a system that doesn't already have Uniaud installed. The "Update Package" has both the Retail build and the Debug build of drivers in it. If you already have Uniaud installed on your system, you can download either the "Complete Install Package" or the "Update Package" zip file and just copy uniaud16.sys and uniaud32.sys over your existing files.

It is not recommended to run the Debug build unless you are testing a specific problem and need to produce a detailed log. Because of the time needed to output the verbose messages in the debug build of the drivers, the debug builds may exhibit some problems that are not present in the retail builds. The debug builds are known to have these problems:

  • A "pop" noise at the end of a sound
  • pause/resume can hang the audio stream
  • skipping forward and/or back in a stream can hang the audio stream
  • changing the volume while a stream is playing can hang the audio stream
  • Playing short sounds in rapid succession can hang the audio stream

A hanging audio stream caused by one of these problems can manifest as stopped audio, or as looping audio. If you see any of these problems AND you are using the debug build of the drivers, please understand that the problem could be because you are using the debug build. You should try the retail build of the drivers before reporting any of these problems.

The current version of Uniaud16 is 1.09.06 and can be used with any version of Uniaud32.

The latest non-beta version of Uniaud32 is 1.9.26 which is based on ALSA 1.0.21.

The latest beta version of Uniaud32 is 2.02.01 which is based on ALSA 1.0.24. This version has had very little testing. It is currently unknown if there are any problems with this version. Try it at your own risk and backup first.

Previous beta versions are also available.

Uniaud32 versions 2.1.x based on ALSA 1.0.23 are known to have problems:

  • A "pop" at the end of sounds
  • Broken Uniaud API
VersionUpdate PackageComplete Install Package
Uniaud16 1.9.5 and Uniaud32 1.9.26
Based on ALSA 1.0.21
(Recommended version)
Uniaud16 1.9.5 and Uniaud32 1.9.24
Based on ALSA 1.0.21
(Previous version)
Uniaud16 1.09.06 and Uniaud32 2.02.01
Based on ALSA 1.0.24
(Beta version)
Uniaud16 1.9.5 and Uniaud32 2.1.3
Based on ALSA 1.0.23
(Beta version)
Uniaud16 1.9.5 and Uniaud32 2.1.1
Based on ALSA 1.0.23
(Previous Beta version)


A Note About Repeating System Sounds

Even though many people think that the Repeating System Sound problem has something to do with Uniaud, THIS IS NOT TRUE. The repeating system sounds problem has nothing at all to do with Uniaud, but instead is caused by SND.DLL and as such will not be addressed here. Please log into and see ticket number 2874 in the BugTracker for the resolution to the Repeating System Sounds problem.

Submitting Tickets

Please read the debugging hints page before opening a ticket.

You must be logged into TRAC to create tickets. Please login with your Netlabs login id. If you do not have a login id, you can request one at If you have troubles acquiring a Netlabs login id send an e-mail to Netlabs Community Mailing List.

When you create a new ticket, please remember these points:

  • Only submit one problem per ticket. If you have experienced more than one problem, open more than one ticket.
  • Always attach the uniaud log created by UniLog.cmd. You can get the UniLog.cmd by downloading this package: Please do not try to create your own logs, use UniLog.cmd. Also attach the log to the ticket as an attachment, do not copy it into the text of the ticket.
  • Only report problems with the current driver version. Older versions are not supported.

Getting the sources

In addition to browsing the sources here, you can check out the sources with your favorite subversion client.

Keep in mind that, unlike cvs, tags and branches are ordinary directories in subversion. With the typical subversion repository layout, it is rather easy to checkout more than you probably intend to. To pull just the trunk version, use something like

mkdir uniaud32
cd uniaud32
svn checkout .


mkdir uniaud16
cd uniaud16
svn checkout .

To update your workspace with the current repository content, use

cd uniaud32
svn update

Building the drivers

Once you have the sources, building the uniaud drivers is relatively straight-forward. You will need the following development tools:

  • OpenWatcom 1.7a or later. (Do not use 1.9 due to inline assembly problems)
  • ilink 5.0 from IBM, or, if using wlink, you need lxlite to bring it down to size.
  • The DDK.

Distributing builds

Public distribution packages always contain both Uniaud16.sys and Uniaud32.sys. See Release Package Procedures for how we go about this.

There is not usually be a reason to publicly release Uniaud16 or Uniaud32 by itself.

When distributing builds of Uniaud16 or Uniaud32 privately to a few people to test, a good practice, to avoid confusion with the public releases, is to change the "fixpak level" to the svn revision number, e.g. "r380". If it does not match any revision number, perhaps because you are testing before committing, you may want to distinguish it with a word like "TESTCASE" or "CUSTOM". None of these labels for private builds should be committed to the svn repo. It is also helpful to set the HOSTNAME environment variable to a unique word that can trace the build back to you if your build system's hostname doesn't already.

Uniaud32 is GPL, so for license compliance any test builds that are distributed privately should not only specify the svn revision number, but also include a patch against that revision if anything differs. This is easily acquired with:

svn diff > my_uni32_from_r380.patch

The experimental branches each follow very different conventions. See the explanation of the Branches and Versioning Info of Uniaud32 for details about working with them.

Debugging and such

Since the drivers are under development, issues are expected. See debugging hints for a guide to techniques and tools that can make solving them easier (we hope).

Alsa Resync

Uniaud derives some of its functionality from the Alsa project. This mean we periodically resync our sources with the latest ALSA sources. This provide both aditional device support as well as defect fixes.

Information for End Users

More information regarding selection, installation, and basic testing may be found on the End User Info page.

Mailing lists

Access to the mailing lists is available both via e-mail and news.


  • Vlad Stelmahosky
  • Pavel Schtemenko
  • Paul Smedley
  • Rich Jerant
  • Steven Levine
  • Mike Greene
  • Allan Holm
  • Andy Willis
  • Brendan Oakley
  • Roderick Klein
  • David Azarewicz

If we forgot anyone, please let us know. It was unintentional.