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

Show the foundation of ALU design, Q. Show the foundation of ALU design? ...

Q. Show the foundation of ALU design? The foundation of ALU design starts with micro-operation implementation. Thus let's first explain how bus can be used for Data transfer m

Two methods of copying a information document, There are basically two meth...

There are basically two methods of copying: Photocopying This is a modified development of photography. It is quite expensive and slow and is not often used for routine rep

Recombination and mutation, Recombination and Mutation: In such a scen...

Recombination and Mutation: In such a scenario the point of GAs is to generate population after population of individuals that represent possible solutions to the problem at h

What are the application-oriented languages, What are the Application-orien...

What are the Application-oriented languages Application-oriented languages are highest level, meaning very easy to write and assembly languages are the lowest, meaning hardest

Software interface, what is software interface #Minimum 100 words accepted...

what is software interface #Minimum 100 words accepted#

Illustrate layout of magnetic disk, Q. Illustrate Layout of Magnetic Disk? ...

Q. Illustrate Layout of Magnetic Disk? Head is a relatively small device capable of reading from or writing to a part of platter rotating beneath it. This gives rise to organiz

Specifying the problem - learning decision trees, Specifying the Problem: ...

Specifying the Problem: Now next here furtherly we now use to look at how you mentally constructed your decision tree where deciding what to do at the weekend. But if one way

Introduction to the sorted arraylist, Consider  a  collection  class  that ...

Consider  a  collection  class  that  is  similar  to  the ArrayList  class,  except  that  elements  are sorted in a certain order. We will call this class SortedArrayList. This c

Limits of traditional payment instruments and overcome, What are the restri...

What are the restrictions of traditional payment instruments? How are such restrictions overcome by electronic payment systems? The restrictions of traditional payment system a

Determine the handles data rate of broad band isdn, Broad Band ISDN handles...

Broad Band ISDN handles data rate of about (A) 64 kbps                                      (B) 100 mbps (C) 5.4 mbps                                    (D) 2.048 mbps

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