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

Where trunks lines are run between, Trunks are the lines that run between ...

Trunks are the lines that run between (A)  subscribers and exchange        (B) switching system and power plant (C)  Local Area Network                (D) switching syste

Explain ip address structure, Q. Explain IP Address Structure? Internet...

Q. Explain IP Address Structure? Internet addresses are divided in five types of classes. Classes were designated A through E. class A address space enables a small number of n

What is radium utilized for, Q. What is radium utilized for? Answer:- ...

Q. What is radium utilized for? Answer:- Radium was previously used in self-luminous paints for nuclear panels, watches, clocks, aircraft switches and instrument dials. In

What is the linkage section, The linkage section is part of a known as prog...

The linkage section is part of a known as program that 'links' or maps to data items in the calling program are working storage. It is the part of the called program where these sh

Secure systems development, Write an academic report on a significant softw...

Write an academic report on a significant software security exploit you have studied. Your report should include details such as, for example: The nature of the software vuln

First-order inference rules - artificial intelligence, First-Order Inferenc...

First-Order Inference Rules -artificial intelligence: Now we have a perfect definition of a first-order model is,in the same way, we may define soundness for first-order infere

What is function scope, What is Function scope Function scope: A labe...

What is Function scope Function scope: A label is the only part of identifier that has function scope. A label is declared implicitly by its use in a statement. Label names m

Target _self, TARGET = "_self" "_self" puts the new document in the s...

TARGET = "_self" "_self" puts the new document in the same window and frame as current document. "_self" works the same as if you hadn't used TARGET at all.

Show a string in assembly language, Q. Show a string in assembly language? ...

Q. Show a string in assembly language? MOV AH, 09H MOV DX, OFFSET   BUFF INT    21H Here data in input buffer stored in data segment is intended to be displayed on mo

What is divide overflow, What is divide overflow?  The division operati...

What is divide overflow?  The division operation might result in a quotient with an overflow. Overflow happens when the length of the registers is finite and will not hold a nu

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