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 number of classes of ip addresses, The total number of class ...

The total number of class of IP address are? The total number of class of IP addresses are 5.

Risk detection, what is meant by risk detection in software project managem...

what is meant by risk detection in software project management

Main problems with evaluation functions, Main problems with evaluation func...

Main problems with evaluation functions: Superlatively, evaluation functions should be quick calculates. Wherever is chance they take a long time to estimate, so after then le

Existential elimination, Existential Elimination : Now we have a sente...

Existential Elimination : Now we have a sentence, A, is with an  existentially quantified variable, v, so then just for every constant symbol k, that it does not appear anywhe

Advantages and disadvantages of structured analysis, Advantages and Disadva...

Advantages and Disadvantages of Structured Analysis With time, you will find out that most customers understand structured methods better than object oriented (OO) methods. As

No class can derive, Make a console application. Add class 'Account' having...

Make a console application. Add class 'Account' having variables as num (integer) name (String), bal (double), ac_code (byte). Describe four different constructors to initialize th

Determine about the virtual private networks, Virtual Private Networks (VPN...

Virtual Private Networks (VPN) In order to encrypt/decrypt all the communication network traffic that passes through the Internet or Intranet, a VPN uses software or hardware.

Implement the concept of true and radix minus one complement, Q. Develop a...

Q. Develop a program to implement the concept of true and radix minus one complement. Program should ask for radix and two numbers from that radix. For that two numbers program

Operating system, explain the various types of computer systems

explain the various types of computer systems

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