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

Explain in detail about the random scan display, Explain in detail about th...

Explain in detail about the Random Scan Display   This device using CRT directs the electron beam only to the parts of the screen where a picture is to be drawn. This kind of d

What is parallel balance point, Q. What is Parallel Balance Point? In ...

Q. What is Parallel Balance Point? In order to execute parallel algorithm on parallel computer K processors are necessary. It should be noted that given input is allocated to

Explain the term instruction cycle, Instruction Cycle The instruction c...

Instruction Cycle The instruction cycle consists of a series of steps required for the execution of an Instruction in a program. A distinctive instruction in a program is compo

3 variable k-maps, 3-variable K-maps have 8 squares which arenormally arran...

3-variable K-maps have 8 squares which arenormally arranged in 4 columns and 2 rows.Columns are labeled with 2 variables. The columns are arranged so that either A or B cha

A variable number of input arguments, Write a function that will get a vari...

Write a function that will get a variable number of input arguments: the length and width of a rectangle, and possibly also the height of a box that has this rectangle as its base.

What is an imperative statement, What is an imperative statement? Ans. ...

What is an imperative statement? Ans. Shows an action to be performed throughout execution of assembled program is an imperative statement.

Convert the octal number 7401 to binary, Convert the octal number 7401 to B...

Convert the octal number 7401 to Binary. Ans. Octal number 7401 to Binary conversion: Every octal digit represents 3 binary digits. To change an octal number to binary number,

Define the Load address for the first word of the program, Load address for...

Load address for the first word of the program is called? Ans. load address origin is known as load address for the first word of the program.

List in a pop-up screen other than full-size stacked list, Can we display a...

Can we display a list in a pop-up screen other than full-size stacked list? Yes, we can show a list in a pop-up screen using the command WINDOW with the additions beginning at

Explain dead code elimination, Explain briefly Dead code Elimination of the...

Explain briefly Dead code Elimination of the commonly used code optimization techniques Dead code Elimination: Code which is unreachable or which does not influence the pr

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