Input-output techniques, Computer Engineering

Assignment Help:

After going through details of device interfaces next point to be discussed is how the interface can be used to support I/O from devices. Binary information received from an external device is generally stored in memory for later processing. Information transferred from central computer in an external device initiates in memory unit. Data transfer between central computer and I/O devices can be handled in some modes. 3 techniques are possible for I/O operation. These are:

  • Programmed input/output
  • Interrupt driven input/output
  • Direct memory access

Figure below gives an general idea of these 3 techniques:

1004_INPUT-OUTPUT TECHNIQUES.png

Figure: Overview of the three Input/ Output

In programmed I/O, I/O operations are fully controlled by processor. The processor executes a program which initiates, directs and terminate an I/O operation. It needs a little special I/O hardware however is quite time consuming for processor as processor has to wait for slower I/O operations to finish. 

With interrupt driven I/O when interface decides that device is ready for data transfer it produces an interrupt request to the computer. Upon detecting external interrupt signal processor stops the task it was processing and branches to a service program to process I/O transfer and then returns to task it was initially performing that result in waiting time by the processor being reduced.

With both interrupt-driven and programmed I/O processor is responsible for extracting data from main memory for output and storing data in main memory during input. What about having a substitute where I/O device may directly store data or retrieve data from memory? This alternative is called direct memory access (DMA). In this mode I/O interface and main memory exchange data directly without involvement of processor.

2405_INPUT-OUTPUT TECHNIQUES1.png

Figure: Three techniques of I/O


Related Discussions:- Input-output techniques

Explain about quine mckluskey method, Q. Explain about Quine McKluskey Meth...

Q. Explain about Quine McKluskey Method? A tabular method was proposed to deal with increasing number of variables called Quine McKluskey Method. This method is appropriate for

Function of osi transport layer, Q. Function of OSI Transport Layer? - ...

Q. Function of OSI Transport Layer? - It takes the information to be sent as well as breaks it into individual packets that are sent and reassembled into a complete message by

Explain problem-oriented and procedure-oriented language, Explain differenc...

Explain difference between Problem-oriented and procedure-oriented language. Problem-oriented and procedure-oriented language: The programming languages which can be utilized

What is a binary tree, What is a binary tree? A binary tree 'T' is desc...

What is a binary tree? A binary tree 'T' is described as A finite set of elements, known as nodes, such that: either (i) or (ii) happens: (i) T is empty (known as the 'nu

What are the ways to truncate guard bits, What are the ways to truncate gua...

What are the ways to truncate guard bits? 1. Chopping 2. Von Neumann rounding 3. Rounding procedure.

Explain the working of a 1-to-16 Demultiplexer, Using a suitable logic diag...

Using a suitable logic diagram explain the working of a 1-to-16 de multiplexer. Ans. 1-to-16 Demultiplexer Working: A demultiplexer obtains in data from one line and directs this

Explain the properties of hypercube, Q. Explain the properties of Hypercube...

Q. Explain the properties of Hypercube? Properties of Hypercube: Hypercube is both edge and node symmetric. The labels of any two neighbouring nodes vary in exactl

What is polling, What is polling? Polling is a scheme or an algorithm t...

What is polling? Polling is a scheme or an algorithm to recognize the devices interrupting the processor. Polling is employed when multiple devices interrupt the processor by o

Define the abstraction of OOA, Define the Abstraction of OOA Now, let ...

Define the Abstraction of OOA Now, let us see how objects can be seen as a problem, and find their associated data and their behaviour. You will notice that an object is an ab

The variables that are declared outside all functions, The variable that ar...

The variable that are declared outside all the functions are called The variables that are declared outside every functions are known as global variable.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd