Friday, 2 August 2013

Australia unveils its most powerful                                      super computer  

Australia's most powerful super computer, Raijin, was unveiled in Canberra. The super computer, unveiled at Australian National University (ANU), is said to be the 27th most powerful computer in the world, it said. 
ANU researchers said the computer can perform the same number of calculations in one hour that 7 billion people with calculators could perform in 20 years. 
Raijin is a part of the new National Computational Infrastructure (NCI) facility at the campus. 
ANU scientist Lindsay Botten said the computer itself is bigger than the size of a house. 
"It has 57,000 processing cores which is something like 15,000 ordinary personal computers [PCs]. It has 160 terabytes of memory which is like 40,000 ordinary PCs. It has 10,000 terabytes of disk which would be like 10,000 ordinary PCs," he said. 
Botten said it will encourage weather scientists and climate change researchers to stay in Australia instead of taking their careers overseas. 

"It keeps Australia at the forefront of global innovation and opens up new horizons for science and research.," he said.

Thursday, 1 August 2013

      ‘Smart‘ homes open doors to hackers

Smart homes that let residents control alarms, locks and more over the internet are opening doors for crooks with hacker skills, according to computer security specialists. 

"The smart home trend is growing, and it evolves quickly into a story of security," Trustwave managing consultant Daniel Crowley told AFP. 

"Connecting things to a network opens up a whole range of vectors of attack, and when you are talking door locks, garage doors, and alarm controls it gets scary." 

Crowley and Trustwave colleague David Bryan found security "pretty poor" on the home networking devices they studied. 

"If someone can access your home network, but doesn't have a key to your home, they can still unlock your door and get in," Crowley said of what he found in gear on the market. 

Trustwave researchers will share their findings with peers at a premier Black Hat security conference in Las Vegas and at the infamous Def Con hacker gathering taking place in that city through the weekend. 

A vulnerability of particular concern to the researchers was that once hackers joined local home networks, perhaps through poorly protected wireless routers or using malware slipped onto computers, they could control devices with no password or other authentication required. 

"The fact that you need to be on someone's local network to exploit these things is not as big a hurdle as you'd imagine," Crowley said. 

And the trend of providing people with smartphone applications for controlling smart home devices while away means that crooks who hack into handsets could potentially grab the reins, according to the researchers. 

There are also ways to use computer "IP" numbers to figure out real-world addresses, and some smart home applications, themselves, reveal location information, according to Trustwave. 

Combing that capability with hacking tools could put an internet age twist on home burglaries, the researchers said. 

"I don't think this will be something that enables the ordinary criminal to do something they weren't doing before," Crowley said. 

"The big risk is that a compromise could give you access to hundreds of thousands of homes all at once; I could see that as an attack someone could actually use to launch a crime spree."
Java supports two types of castings – primitive data type casting and reference type casting. Reference type casting is nothing but assigning one Java object to another object. It comes with very strict rules and is explained clearly in Object Casting. Now let us go for data type casting.
Java data type casting comes with 3 flavors.
  1. Implicit casting
  2. Explicit casting
  3. Boolean casting.
1. Implicit casting (widening conversion)
A data type of lower size (occupying less memory) is assigned to a data type of higher size. This is done implicitly by the JVM. The lower size is widened to higher size. This is also named as automatic type conversion.
        int x = 10;                    // occupies 4 bytes
        double y = x;                  // occupies 8 bytes
        System.out.println(y);         // prints 10.0
In the above code 4 bytes integer value is assigned to 8 bytes double value.
2. Explicit casting (narrowing conversion)
A data type of higher size (occupying more memory) cannot be assigned to a data type of lower size. This is not done implicitly by the JVM and requires explicit casting; a casting operation to be performed by the programmer. The higher size is narrowed to lower size.
       double x = 10.5;             // 8 bytes
       int y = x;                   // 4 bytes ;  raises compilation error
In the above code, 8 bytes double value is narrowed to 4 bytes int value. It raises error. Let us explicitly type cast it.
       double x = 10.5;                  
       int y = (int) x;
The double x is explicitly converted to int y. The thumb rule is, on both sides, the same data type should exist.

3. Boolean casting
A boolean value cannot be assigned to any other data type. Except boolean, all the remaining 7 data types can be assigned to one another either implicitly or explicitly; but boolean cannot. We say, boolean is incompatible for conversion. Maximum we can assign a boolean value to another boolean.
Following raises error.
       boolean x = true;
       int y = x;                    // error
       boolean x = true;
       int y = (int) x;           // error
byte –> short –> int –> long –> float –> double
In the above statement, left to right can be assigned implicitly and right to left requires explicit casting. That is, byte can be assigned to short implicitly but short to byte requires explicit casting.

Following char operations are possible.
public class Demo
    public static void main(String args[]) 
        char ch1 = 'A';
        double d1 = ch1;
        System.out.println(d1);              // prints 65.0
        System.out.println(ch1 * ch1);       // prints 4225 , 65 * 65
        double d2 = 66.0;
        char ch2 = (char) d2;
        System.out.println(ch2);             // prints B
Object casting (reference casting) discusses casting between objects of different classes involved in inheritance.
Your one stop destination for all data type conversions
byte TOshortintlongfloatdoublecharboolean
short TObyteintlongfloatdoublecharboolean
int TObyteshortlongfloatdoublecharboolean
float TObyteshortintlongdoublecharboolean
double TObyteshortintlongfloatcharboolean
char TObyteshortintlongfloatdoubleboolean
boolean TObyteshortintlo