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

Concept of multithreading, Concept of Multithreading: This problem ris...

Concept of Multithreading: This problem rises in design of large scale multiprocessors like MPP. So a solution for optimizing this latency must be acquired at. The idea of Mul

Mathematical simulation and modeling applications, Mathematical Simulation ...

Mathematical Simulation and Modeling Applications The tasks including modeling and mathematical simulation require a lot of parallel processing. Three basic formalisms in model

What is a session in php, A session is a logical object formed by the PHP e...

A session is a logical object formed by the PHP engine to permit you to preserve data across subsequent HTTP requests. There is only one session object available to your PHP scr

Error detection mechanism must be in-built, Error detection mechanism may i...

Error detection mechanism may include checking mechanical and data communication errors. These errors must be reported to processor. The illustrations of kind of mechanical errors

Program size for different instruction set approaches, Q. Program size for ...

Q. Program size for different Instruction Set Approaches? Assumptions: Complex Instruction is: Add C, A, B having 16 bit addresses and 8 bit data operands All opera

Explain how presentation layer helps in establishing, Explain how presentat...

Explain how presentation layer helps in establishing and processing data in End to End layers. The idea of the presentation layer is to stand for information to the communicati

Where can i find my user preferences?, Customized User Preferences offer tr...

Customized User Preferences offer tremendous versatility to your individual Bugzilla experience. Let's plunge into what you can do! The first step is to click the "Edit prefs" link

Explain pre-emptive scheduling, Explain Pre-emptive scheduling? Pre-em...

Explain Pre-emptive scheduling? Pre-emptive scheduling: in its approach, center processing unit can be taken away from a process if there is a require while in a non-pre-empt

Advantage of using interrupt initiated data transfer, What is the advantage...

What is the advantage of using interrupt initiated data transfer over transfer under program control without interrupt? In the interrupt initiated data transfer, the processor

What is preemptive and nonpreemptive scheduling, What is preemptive and non...

What is preemptive and nonpreemptive scheduling? Under nonpreemptive scheduling once the CPU has been allocated to a process, the process keeps the CPU unless it releases the C

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