What is failure detection and failure masking in distributed system ?

A distributed system

Is a model in which components located on networked computers communicate and coordinate their actions by passing messages. The components interact with each other in order to achieve a common goal.

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Let’s create 8 bit LED binary counter

Here, I am going to discuss how to create 8 bit LED binary counter using Arduino micro controller board . This binary counter  displays  decimal numbers from 0 to 255 in 8 bit binary format using 8 LEDs, where as 1 is represented by lighting only left most  (2)  LED.Number  representation will be increased from 0 to 255 automatically .
Following figure shows several lighting patterns according to the decimal value from 0 to 7.

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How to install eclipse juno IDE in ubuntu 16.04 ?

Are you tired of trying to install eclipse IDE in ubuntu 16.04 ? You don’t have to worry about that moreover. In this article, I am going to describe how to install Eclipse juno IDE(from Eclipse Juno SR2 Packages, that has developed for Java EE Developers) in ubuntu 16.04.Eclipse is an integrated development environment (IDE) used in computer programming, and is the most widely used Java IDE.

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How to install Apache Maven & Apache Hadoop in Ubuntu 16.04


In this article I  am going to discuss how to setup Maven and Hadoop. The steps for all two frameworks are always the same:
                    1.Decompress the archive
                    2.Add the correct console variable
                    3.Test the correctness of the installation

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How to install java in Ubuntu 16.04 using the terminal

In this article, I am going to describe how to install java in Ubuntu 16.04 using the terminal.


First I am going to add Oracle’s PPA(Personal Package Archive) using terminal command.


You can open terminal easily by pressing Ctrl + Alt + t


Then type and enter below code.


         sudo add-apt-repository ppa:webupd8team/java            


After that update your package repository using this terminal command.


        sudo apt-get update

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Necessary conditions for deadlocks in computing

Earlier I have described about deadlock in computing. In this article, I am going to discuss about  the necessary conditions, those hold simultaneously in a system to arise deadlock situation.
We can discuss these necessary conditions more precisely in terms of a directed graph called a system resource-allocation graph. So I used related  diagrams with description.
In this diagrams rounded rectangles visualize a resource and dots inside it visualize number of instances of the resource.Circles visualize processes.
Mutual Exclusion
In this scenario, there is a one resource(R1) with non-shareable mode. That means only one process can be used at a time. If another process requests that resource(P1), the requesting process(P1) must be wait until the resource has been released by first process(P2).

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What is deadlock in computing?


In a multi-programming environment, Processes want resources to do their corresponding process. When a process requests a resource and if it is not available at that instant, then the process enters to a waiting state. Sometimes this process can’t get out from the waiting state because the process has been hold by another process. This situation is called a deadlock.

Let’s discuss this situation in detail.

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Simple DIY project using HC-SR04 Ultrasonic Sensor

You can create a circuit to measure the water level of a water tank using this HC-SR04 Ultrasonic Sensor. You only have to add few lines in to the code that I used to display measured distance from this sensor. Revised code is given below.
int echoPin = 2;  //Define Echo pin
int trigPin = 3;     // Define Trig pin
long  inches, duration, cm;   //Define variables
int height=300; //define depth of tank in cm
int firstLED = 4; // define LEDs pin
int secondLED = 5;
int thirdLED = 6;
int fourthLED = 7;
void setup() {
Serial.begin (9600);
pinMode(trigPin, OUTPUT);  //Define output pin
pinMode(firstLED, OUTPUT);
pinMode(secondLED, OUTPUT);
pinMode(thirdLED, OUTPUT);
pinMode(fourthLED, OUTPUT);
pinMode(echoPin, INPUT);  //Define input pin

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Get to know about Ultrasonic Sensor HC-SR04

Ultrasonic Sensor HC-SR04 is used to measure distance. We can find precise distance to an object from sensor, or can used to detect when something is within range of the sensor. It can measure distance with high accuracy from 2cm to 400 cm. Its operation is not affected by sunlight or black material .Because it uses sound to measure distance.
Ultrasonic range finder measure distance by emitting a pulse of ultrasonic sound that travels through the air until it hits an object. It measure how long it takes the sound pulse to travel in its round trip journey back to the sensor when the pulse hits the object. Then it sends an electrical signal to the Arduino with information about how long it took for the sonic pulse to travel.

Ultrasonic range finder has 2 transducers.

  •         Transmitting transducer
  •     Receiving transducer


Transducers convert mechanical forces into electrical signals. The transmitting transducer converts an electrical signal into the ultrasonic pulse using MAX3232 IC. Receiving transducer converts the ultrasonic pulse into an electrical signal using LM324 IC. The length of this high voltage signal is equal to the total time of pulses take to travel from the transmitting transducer.

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