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

forensics capability relevant to a honeynet server, A local government org...

A local government organisation needs to deploy a honey net. To this end you are to deploy a honeynet based on the supplied network diagram (separate download) that should give sop

Convert, haw to convert context free grammar to regular grammar

haw to convert context free grammar to regular grammar

Assessing heuristic searches , Assessing Heuristic Searches: Given a p...

Assessing Heuristic Searches: Given a particular problem you want to build an agent to solve, so there may be more than one way of justifying it as a search problem, more than

Explain a TTL NAND gate and its operation, Give the circuit of a TTL NAND g...

Give the circuit of a TTL NAND gate and explain its operation in brief. Ans: Operation of TTL NAND Gate: Fig.(d) Demonstrates a TTL NAND gate with a totem pole output.

Write a program to input an address, Write a program to input an address i....

Write a program to input an address i.e. 20 Hex and read the byte (char) contents of that address   Answer   include void main() { char prompt; Date: 26th August 2012

Probabilistic hough transformation, The probabilistic Hough transform uses ...

The probabilistic Hough transform uses random sampling instead of an accumulator array. In this approach the number of random samples r, is not specified in the OpenCV call, but

What is an interrupt, What is an interrupt?  An interrupt is an event t...

What is an interrupt?  An interrupt is an event that causes the implementation of one program to be suspended and another program to be implemented.

Delete the leaves of a binary tree, Write a recursive algorithm to delete t...

Write a recursive algorithm to delete the leaves of a binary tree. Programming Requirements You must use the binary search tree code provided.  Each algorithm must be impleme

What is a table attribute, What is a Table attribute? The table's attr...

What is a Table attribute? The table's attributes verifies who is responsible for maintaining a table and which types of access are permitted for the table.  The most signific

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