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

Determine the binary equivalent of hexadecimal FA, The binary equivalent of...

The binary equivalent of (FA) 16   is ? Ans. (FA) 16 = (11111010) 10

What is an compiled languages, What is an compiled languages In compile...

What is an compiled languages In compiled languages the instructions into machine code and kept them  in a separate file for later implementation. Many modern compilers can com

COMPUTER SYSTEM, Classify computer systems according to capacity. How they ...

Classify computer systems according to capacity. How they are different from computers according to the classification of technology. Provide comparative study also.

Credit line, The Credit Line The Credit Line is a set of informational f...

The Credit Line The Credit Line is a set of informational facts usually found below or beside a picture of a work of art. Should the picture appear in a book, magazine, poster,

Computer architecture, describe the block diagram of a system showing the f...

describe the block diagram of a system showing the following microprocessor memory system buses

What is program-controlled i/o, What is program-controlled I/O? In prog...

What is program-controlled I/O? In program controlled I/O the processor repeatedly checks a status flags to achieve the needed synchronization among the processor and an input

Example application - canonical genetic algorithm, Example Application: ...

Example Application: There are many fantastic applications of genetic algorithms. Conceivably my favorite is their usage in evaluating Jazz melodies done as part of a PhD proj

Mapping, what is transform mapping and transaction mapping?

what is transform mapping and transaction mapping?

Define file record length, Define File record length ? File record leng...

Define File record length ? File record length must be selected to match the data characteristics.

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