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

State the implementation of a security policy, State the implementation of ...

State the implementation of a security policy The implementation of a security policy should invariably cover all parameters of security such as physical access to the server,

What is a sparse matrix, What is a sparse matrix? Sparse Matrix A m...

What is a sparse matrix? Sparse Matrix A matrix in which number of zero entries is much higher than the number of non-zero entries is known as sparse matrix. The natural me

Describe critical directive in fortan, Q. Describe Critical Directive in FO...

Q. Describe Critical Directive in FORTAN? The critical directive permits one thread executes associated structured block. When one or more threads attain critical directive the

Define electronic data interchange, Electronic Data Interchange (EDI ) is u...

Electronic Data Interchange (EDI ) is used by companies for transactions that happen on regular basis to a pre-determined format. It is one of the electronic commerce technologies.

Nix commands, reate a directory "Unix" under your home directory. Command(...

reate a directory "Unix" under your home directory. Command(s): ………………………………………….

What is a heap, What is a heap? A complete binary tree, every of whose ...

What is a heap? A complete binary tree, every of whose elements contains a value that is  greater than or equal to the value of every of its children is known a Heap

Cemistry, Discuss scales and sludge

Discuss scales and sludge

What is device drivers, A device driver is software interface that manages ...

A device driver is software interface that manages communication with and control of a particular I/O device or type of device. It is task of device driver to convert logical reque

What is pattern, What is pattern? A pattern is a proven solution to a g...

What is pattern? A pattern is a proven solution to a general problem. Lots of patterns are used. There are patterns for analysis, architecture, design and execution. Patterns 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