Sound glitches

Nov 1, 2007 12:09 GMT  ·  By

Microsoft's latest operating system, Windows Vista, advertised as an evolution in comparison with its predecessor, Windows XP, is nothing short of a resource hog, swallowing every crumb of CPU cycles and digesting even the last bits of RAM thrown at it. And yet, while the Windows client has been experiencing issues related to compatibility, stability, and reliability, the overall performance is also affected in a variety of scenarios, impacting even the audio infrastructure of the product. Microsoft, though the voices of Nick White, Vista Product Manager, and Steve Ball, Senior Program Manager for Sound in Vista, acknowledged the fact that sound problems can plague the platform, just as easy as other issues.

"Windows is a rich and complex OS designed for multi-tasking users whose tasks must share access to scarce system hardware and resources. Unfortunately, despite multiple decades of incredible advances in PC and CPU architectures, there are non-trivial, complex interactions between applications, processes, and devices in even the most advanced personal computers that make a supposedly "easy" task -- like playing back music without occasional glitches -- much more difficult than it may seem at first glance," Ball explained.

Because Vista is by no means a single function device. The operating system, stretched between multiple simultaneous tasks, each taxing the hardware resources available, delivers a fertile scenario for glitches. The combination of multiple processes feeding concomitantly on what the hardware has to offer generates inherent resource conflicts, when attempting to satisfy the needs of diverse activities, equally and simultaneously power-hungry.

"But because of the multi-tasking nature of Windows and the vast array of new and legacy hardware in the ~1B PCs that are used to playback music today, this allegedly simple process is made more complex by the resource sharing that occurs between applications and hardware. For example, it is not uncommon for certain older devices driver to occasionally "lock out" the CPU for 10-50ms, thereby causing obvious audio glitches. This is just one example of the kinds of complex hardware, driver, and OS interactions that can cause glitches," Ball said.

Users of Microsoft's latest operating system have experienced various errors in Vista's sound playback from gaps, to no audio, to interruptions and to skipping. In the end, the audio glitches in Vista are not only generated by the way the operating system handles the division of hardware resources, but also through the defective management performed by applications, device drivers and processes introduced into the operating system.

For this end, hardware will always provide finite resources, that can simply fail to account for the entire volume of tasks performed on top of the operating system or by the platform itself. "Some of the common sources of glitches today include: CPU starvation; GPU starvation; resource contention from devices and drivers (sometimes called "IO contention"); network devices and, of course ... bugs in applications, OS, drivers and/or hardware," Ball added.