Input/ OutputBy Mohit Sehgal

What is Input/Output of a Computer?

• Connection with Machine

• Every machine has I/O (Like a function)

• In computing, input/output, or I/O, refers to the communication between an information processing system (such as a computer), and the outside world possibly a human, or another information processing system.

KeyboardUses an arrangement of buttons or keys,

to act as mechanical levers or electronic switches.

MousePointing device that functions by

detecting two-dimensional motion relative to its supporting surface

Types of I/O

•Interrupt I/O

•Programmed I/O

•DMA I/O (Direct Memory Access)

Interrupt I/O

In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution.

Interrupt I/O

• CPU does not need to wait

• I/O Module interrupts when it is ready

Programmed I/O

Method of transferring data between the CPU and a peripheral such as a network adapter or an ATA storage device

Happens when software running on the CPU uses instructions that access I/O address space

Programmed I/O

CPU has control over the I/O

Downfall:

Uses a lot of CPU time

Direct Memory Access I/ORefers to data transfers initiated by a

device to access system memoryAllows certain hardware subsystems

within the computer to access system memory for reading and/or writing independently of the central processing unit

DMA I/ODMA controller takes over from CPU for I/O

DMA takes the load from the CPU

Input/ Output ProcessCPU checks I/O module device statusI/O then returns its statusCPU requests data transfer if I/O is readyI/O module gets data from deviceTransfers it to CPUOutput

Input Output I/O are getting more advancedNow I/O are doing the entire transferThis takes the strain off of CPU

Future of I/O