System software and hardware support considerations for digital video and audio computing

Digital video and audio (DVA) input/output presents special problems to a computer system´s underlying support software and hardware. The author explores what generic functionality the I/O bus, device controllers, and system software should provide to adequately support DVA applications executing on modern workstations connected by fast local area networks. The problems are due to the high data rates and timing constraints of DVA. To address these problems, more efficient data movement (minimizing data copying wherever possible) and better control over low-level timing of I/O transfers are required. System software must take better advantage of I/O bus functionality such as burst-mode transfers and peer-to-peer communication. While complex embedded systems are discouraged, controllers may be equipped with special-purpose functionality which causes a reduction in data movement, such as compression/decompression hardware. System I/O software should support separation of data transfer and I/O control.