I/O Channel And Precessors
by Che safwan
1. I/O channel architecture
1.1. 1. Selector
1.2. 2. Multiplexor
2. Definition
2.1. channel I/O is a high-performance input/output (I/O) architecture that is implemented in various forms on a number of computer architectures, especially on mainframe computers. In the past, channels were generally implemented with custom processors, variously named channel, peripheral processor, I/O processor, I/O controller, or DMA controller.
3. Evolution of I/O Function
3.1. 1. The CPU directly control a peripheral device.
3.2. 2. A controller or I/O uses programmed I/O module is added.
3.3. 3. Interrupts are employed. The CPU need to spend time waiting for an I/O operation to be performed to increasing efficiently.
3.4. 4. I/O module direct access to memory via DMA. It now can move a block of data to or from memory without involving CPU.
3.5. 5. I/O module enchanced to processor with a specialized instruction set tailored for I/O.
3.6. 6. I/O module has a local memory of its own with this architecture of I/O device can be controlled with minimal CPU.
