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

What is tri-state logic, What is Tri-state logic ? Ans. Tri-state Logi...

What is Tri-state logic ? Ans. Tri-state Logic: In common logic circuits, there are two states of the output, as LOW and HIGH. If the output is not in the LOW state, this

Social media strategy design, For this phase of the project you are require...

For this phase of the project you are required to formulate a social media strategy for a product/service/business/concept/charity...etc. the strategy can include technologies such

Name the concepts of object oriented, Name the concepts of Object oriented ...

Name the concepts of Object oriented There are various concepts of object oriented analysis Abstraction, Encapsulation, Identity, Modularity, Hierarchy, Typin

What methods can be overridden in java, In C++ terminology, all public meth...

In C++ terminology, all public methods in Java are virtual. Thus, all Java methods can be overwritten in subclasses except those that are declared final, private and static.

What is jmx, JMX is native to the Java programming language. As a result, i...

JMX is native to the Java programming language. As a result, it offers natural, efficient, and lightweight management extensions to Java-based functions. It has of a set of specifi

Define top-down parsing techniques, Define Top-down parsing Techniques ...

Define Top-down parsing Techniques Top-down parsing can be observed as an attempt to find left-most derivations of an input-stream through searching for parse trees using a top

Define synchronous bus, Define synchronous bus. Synchronous buses are t...

Define synchronous bus. Synchronous buses are the ones in which every item is transferred during a time slot(clock cycle) known to both the source and destination units. Synchr

Define the pulse-triggered (master-slave) flip-flops, Define the Pulse-Trig...

Define the Pulse-Triggered (Master-Slave) Flip-flops? The term pulse-triggered signify that data are entered into the flip-flop on the rising edge of the clock pulse, though th

What are the requirements for a swapper to work, What are the requirements ...

What are the requirements for a swapper to work? The swapper works on the highest scheduling priority. Firstly it will look for any sleeping method, if not found then it will

Limitations of experts system, 1. It is hard even for a highly skilled ex...

1. It is hard even for a highly skilled experts to abstract good situational assessment when he is under time pressure. 2. Expert systems perform well with specific t

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