Input/Output of a Computer Presented by: Jose Reyes Jose

Overview  What is input and output?  Different types of I/O interfaces  Examples of input devices  Examples of output devices

Input and Output The collection of interfaces that different functional units (sub-systems) of a system use to communicate with each other, or to the signals(data) sent through those interfaces. Inputs are the signals received by the unit, and outputs are the signals sent from it. I/O devices are used by a person (or another system) to communicate with a computer.sub-systems

In General: Input and output allows the computer to obtain information from the outside world, and send the results of its work back to it. Cont…

Different types of I/O  Programmed I/O  Interrupt Drive I/O  Direct Memory Access

Programmed I/O The programmed I/O(PIO) interface was the original method used to transfer data between the CPU (through the IDE controller) and device. The PIO interface is grouped into different modes that correspond to different transfer rates. The electrical signaling among the different modes is similar - only the cycle time between transactions is reduced in order to achieve a higher transfer rate. All devices support the slowest mode - Mode 0. By accessing the information registers, the CPU is able to determine the maximum transfer rate for the device and configure the IDE controller for optimal performance.IDE

Interrupt  an interrupt is a signal from a device which typically results in a context switch.  Interrupts were originated to avoid wasting the computer's valuable time waiting for electronic events.  Instead, the computer was able to do other useful work while the event was pending.

Direct Memory Access(DMA)  A smart I/O that can transfer data into memory directly  Far more efficient than Programmed and Interrupt I/O  Allows CPU to execute other instructions while I/O is being performed

Examples of input devices  Keyboard/Mouse  Scanner  CD-Rom  Game Controller  Digital Camera

Examples of output devices  Monitor  Printer  Speakers

Input/Output Devices  Hard Drive  Mp3 Player  Flash Memory  CD/DVD Burners

Conclusion  It had never been easier to connect a device to your computer.  Many of today’s devices plug into the computer using the USB port.  USB port is very versatile