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

Electric typewriter in information distribution, Electric typewriter : Ele...

Electric typewriter : Electric typewriters are similar to standard typewriters but with an electronic motor taking the place of human energy. It is much faster than the standard m

Registers - processor, These will be independent of each other and will not...

These will be independent of each other and will not affect to each other, and so they can be fed into two different implementations units and run in parallel. The ability to remov

C programming, write a program to find the area under the curve y=f(x) betw...

write a program to find the area under the curve y=f(x) between x=a and x=b,integrate y=f(x) between the limits of a and b

What are the basic components of dialog program, What are the basic compone...

What are the basic components of dialog program? Screens (Dynpros) Every dialog in an SAP system is controlled by dynpros. A dynpros having of a screen And its flow log

Explain the isa and hasa class relationships, How would you implement each ...

How would you implement each in a class design? Ans) A specialized class "is" a specialization of another class and, thus, has the ISA relationship with the other class. An Em

Explain extranet, Extranet : Extranet is Extension of an Intranet that ...

Extranet : Extranet is Extension of an Intranet that makes the latter accessible to outside companies or individuals with or without an intranet. It is also described as a coll

Threads, First, remember that different processes keep their own data in di...

First, remember that different processes keep their own data in distinct address spaces. Threads, on the other hand, explicitly share their entire address space with one another. A

Project, write a programme to simulate a train station to automate

write a programme to simulate a train station to automate

What is access latency and rotation speed, Q. What is Access latency and Ro...

Q. What is Access latency and Rotation Speed? Access latency: A disk access basically moves the arm to selected cylinder and waits for rotational latency that may take less t

What are the facilities of a debug monitor, What are the facilities of a de...

What are the facilities of a debug monitor? The facilities of a debug monitor are given below: a. Setting breakpoints into the program b. Initiating a debug conversation

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