I/O Off-Level Control in a Virtual Resource Manager
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
By providing an I/O off-level control in a Virtual Resource Manager (VRM), the Second Level Interrupt Handler (SLIH) can reduce latency for all equal and lower priority classes. Normally, a SLIH runs to completion in the VRM, preventing all I/O devices from interrupting unless they are of a higher priority class. It is possible to work around this by designing the device driver to be a SLIH and a device manager process. This approach, however, adds significant path length (an additional level of queueing) which could result in performance degradation and complexity in debugging the code. The solution to this problem is to provide an I/O off-level control in the VRM.