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

Structural hazards - computer architecture, Structural hazards - computer a...

Structural hazards - computer architecture: A structural hazard takes place when a part of the processor's hardware is required by 2 or more than two instructions at the same

Illustarte basic flip-flops, Q. Illustarte Basic Flip-flops? Let's firs...

Q. Illustarte Basic Flip-flops? Let's first see a ordinary latch. A latch or flip-flop can be created employing two NOR or NAND gates. Figure (a) presents logic diagram for S-R

Explain essential properties of distributed operating system, Describe the ...

Describe the essential properties of the Distributed Operating System Essential properties of Distributed operating systems: Sharing resources Calculation speed-up

Give the meaning of spc, SPC stands (A)   Standard Protocol Control ...

SPC stands (A)   Standard Protocol Control (B)   Stored Program Control (C)  Signaling and switching Centre (D)  Signaling Process Center Ans: SPC repres

Discuss the general procedure of booting process, Question 1 What are t...

Question 1 What are the different schemes in power management? Explain 2 Explain the functions of parallel port in detail 3 (a) List and explain the functions of keyboard

Describe set-associative mapping, Q. Describe Set-Associative Mapping? ...

Q. Describe Set-Associative Mapping? A third type of cache organization known as set-associative mapping is an improvement on direct mapping organization in that every word of

Convert the following into pos form, Q. Convert the following into POS form...

Q. Convert the following into POS form 1.  (AB + C + DC)(AB + BC + D) 2.  WYZ + XYZ + W'X'Y + W'XYZ 3.  XY + XZ + X'YZ' 4.   (A+B'+C) (AB+AC') 5.   F(A,B,C,D)=M(0,3,

Pre order given find post order ?, The preorder traversal sequence of a bin...

The preorder traversal sequence of a binary search tree is 30, 20, 10, 15, 25, 23, 39, 35, 42. Which one of the following is the postorder traversal sequence of the same tree?

Determine 127.0.0.1 is which type of address, 127.0.0.1 is a? 127.0.0.1...

127.0.0.1 is a? 127.0.0.1 it is a loop-back address.

What is garbage collection and what is it used for, In computer science, ga...

In computer science, garbage collection (GC) is a form of automatic memory management. The garbage collector, or just collector, attempts to reclaim garbage, or memory occupied by

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