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

Loop used to show properties, Normal 0 false false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4  A loop invariant is

Observations of high level language program, Q. Observations of High Level ...

Q. Observations of High Level Language Program? Observations Integer constants appeared nearly as frequently as structures or arrays. Most of the scalars were foun

How call processing takes place, How call processing takes place? Fund...

How call processing takes place? Fundamental Call Procedure: Fig. demonstrates a simplification diagram exemplifying how two telephone sets (as subscribers) are interconnecte

Illustrate working of magnetic bubble memories, Q. Illustrate working of Ma...

Q. Illustrate working of Magnetic Bubble Memories? In many materials like garnets on applying magnetic fields certain cylindrical areas whose direction of magnetization is oppo

Equivalences & rewrite rules - artificial intelligence, Equivalences & Rewr...

Equivalences & Rewrite Rules - artificial intelligence: Along with allowing us to verify trivial theorems, tautologies make us able to establish that definite sentences are say

Define categorization of parallel computers, Types Of Categorization Th...

Types Of Categorization The subsequent categorization of parallel computers has been identified: 1)  Categorization based on the instructions and data streams  2)  Catego

Propositional versions of resolution, Propositional versions of resolution:...

Propositional versions of resolution: Just because of so far we've only looked at propositional versions of resolution. However in first-order logic we require to also deal wi

What are interrupts, What are interrupts?  Interrupt: An interrupt i...

What are interrupts?  Interrupt: An interrupt is a hardware mechanism which enables an external device, classically input/output devices, to send a signal to the CPU. An int

Shell scripting, Write a script called addnames that is to be called as fol...

Write a script called addnames that is to be called as follows, where classlist is the name of the classlist file, and username is a particular student''s username. ./addnames cla

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