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

Multithreaded architecture, Multithreaded Architecture:  It is clear now th...

Multithreaded Architecture:  It is clear now that if we give many contexts to multiple threads, then processors with multiple contexts are known as multithreaded systems. These sys

What is input-output processors, Q. What is Input-output processors? le...

Q. What is Input-output processors? let's briefly summarize the development in area of input/output functions. These can be briefed as below: 1. CPU directly controls a peri

Different search strategies- artificial intelligence, Different search stra...

Different search strategies- artificial intelligence: To help us think about the different search strategies, we use two analogies. Firstly, we suppose that the professor keep

Illustarte basic flip-flops, Q. Illustarte Basic Flip-flops? Let's firs...

Q. Illustarte Basic Flip-flops? Let's first see a ordinary latch. A latch or flip-flop can be created employing two NOR or NAND gates. Figure (a) presents logic diagram for S-R

What is icon, An icon is a picture used to show an object. Some example obj...

An icon is a picture used to show an object. Some example objects are: data files, program files, folders, email messages, and drives. Every type of object has a dissimilar icon. T

Define race condition, Define race condition.  When several process acc...

Define race condition.  When several process access and manipulate similar data concurrently, then the outcome of the implementation depends on particular order in which the ac

Describe the characteristics of mainframes, Problem 1 (a) List and desc...

Problem 1 (a) List and describe the characteristics of mainframes, minicomputers and microcomputers. (b) Briefly describe what is meant by electronic commerce and what b

The advantage of using a database management system, The advantage of using...

The advantage of using a Database Management System The advantage of using a Database Management System for a data store is that databases have mechanisms for describing data,

Quick sort , Write Quick sort non recursive program

Write Quick sort non recursive program

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