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

Processing elements (pes) -array processing, Processing elements (PEs)  : E...

Processing elements (PEs)  : Every processing element consists of ALU, local memory and its registers  for storage of distributed data. This PEs has been interconnected via an inte

What does realized mean, Realized mean that the component has been painted ...

Realized mean that the component has been painted on screen or that is prepared to be painted. Realization can take place by invoking any of these methods. setVisible(true), show()

Message passing programme development environment, In a multicomputer syste...

In a multicomputer system the computational load amid different processors should be balanced.  To pass information between different nodes message passing technique is used. The p

Human intelligence in culture - artificial intelligence, Human intelligence...

Human intelligence in culture: Understand human intelligence in culture  "AI" can be seen as just the latest tool in the philosopher's toolbox for answering questions about

Design a mod-5 synchronous counter using J-Kflip-flops, What are synchronou...

What are synchronous counters? Design a Mod-5 synchronous counter using J-K Flip-Flops. Ans. Synchronous Counters : It means that all flip-flops are clocked concurrently. T

Explain the term- macro, Explain the term- macro? A term macro is a set...

Explain the term- macro? A term macro is a set of instructions, which can be executed repeatedly. It is useful for automating certain routine tasks like printing reports etc. T

Determine about the web authoring tools, Web authoring tools CGI was cons...

Web authoring tools CGI was considered excellent in the beginning since it was also open standard. The only drawback it suffered was that it was slow. Major software developers v

Example on cyclic distribution of data, Q. Example on Cyclic Distribution o...

Q. Example on Cyclic Distribution of data? !HPF$ PROCESSORS P1(4) !HPF$ TEMPLATE T1(18) !HPF$ DISTRIBUTE T1(CYCLIC) ONTO P1 The result of these instructions is display

Calculus, i want an assignment on application of integraton and my topc of ...

i want an assignment on application of integraton and my topc of assifment is area under the curve includin solved examples

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