QoS Support and an Analytic Study for USB 1.x/2.0 Devices

With the recent advances in the operating system design and hardware technology, resource management strategies in computing systems begin to draw more attention from system engineers. Exploring all possible strategies is complicated by the modularization design, which usually divides an operating system into several components. The concept of modularization separates and isolates the management of different types of system resources. The resource management issues are no longer dominated by CPU scheduling policies. Even if a process obtains a good service from the CPU scheduler, it does not guarantee that the process could always access disks as it wishes or use any specific Universal Serial Bus (USB) devices with proper services. The definition of “quality of service” (QoS) could also be different when different resources are considered: for an I/O interface, QoS might be in terms of bandwidth reserved, while QoS for memory management might be in terms of the number of bytes allocated in memory. Different QoS definitions and enforcement mechanisms for different components of an operating system are needed for servicing applications with a proper QoS.