HPJava

L.Indraneel(08P61A1222)

Introduction to Java

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java Platform

 Java is currently one of the most popular programming languages in use, particularly for client-server web applications, with a reported 10 million users.

Characteristics of Java

Java is simple

Java is object-oriented

Java is distributed

Java is interpreted

Java is robust

Java is secure

Java is portable

Java’s performance

Java is multithreaded

Java is dynamic

Object Oriented Concepts

Inheritance Polymorphism Encapsulation Abstraction

Why Java?

It’s the current popular languageIt’s almost entirely object-orientedIt has a vast library of predefined objects and

operationsIt’s more platform independent

this makes it great for Web programmingIt’s more secure

Java programs

Two kinds

Applicationshave main()run from the OS prompt

Appletshave init(), start(), stop(), paint(),

update(), repaint(), destroy()run from within a web page

What is HPJava?HPJava stands for “high performance java”

HPJava is a programming language extended from Java to support parallel programming, especially (but not exclusively) data parallel programming on message passing and distributed memory systems, from multi-processor systems to workstation clusters 

Difference between Java and

HP JavaJava already provides parallelism through

threads. But that model of parallelism can only be easily exploited on shared memory computers.

HP Java is targeted at distributed memory parallel computers (most likely, networks of PCs and workstations).

HPJava History

Inspired by HPF(high performance Fortran) HPJava project started around 1997

HPJava lifts some ideas directly from HPFSyntax was simpler and there was scope to 

extend the features

Features of HPJava

HP Java adds to Java a concept of multi-dimensional arrays called “multiarrays”

To support parallel programming, these multiarrays are extended to “distributed arrays”.

The new distributed datastructures are cleanly integrated into the syntax of the language

Architecture of HP Java

Front-End Architecture

Issues in the language design

1 Extending the Java languageHPJava can bound to other languages like C,

C++ and Fortran. But Java is a convenient base language because it provides full object-orientation convenient for describing complex distributed

It has been noted elsewhere that Java has various features suggesting it could be an attractive language for science and engineering

2 Datatypes in HPJava

In HPJava, variable names are divided into two sets. In general those declared using ordinary Java syntax represent local variables and those declared with [[ ]] represent global variables

3. Programming convenience

The language provides some special syntax for the programmer's convenience

Unlike the syntax for data declaration, which has fundamental significance in the programming model, these extensions are purely provide syntactic conveniences.

Advantages

HPJava adds to Java is a multi-dimensional array, or multiarray, with properties similar to the arrays of Fortran

HPJava supports parallel programming on distributed memory (and shared memory) parallel computers

Any ordinary Java class can be invoked from an HPJava program without recompilation

A translated and compiled HPJava program is a standard Java class file that can be executed by a distributed collection of Java Virtual Machines

Disadvantages

Many of the features of HPJava would be hard or impossible to achieve as Java libraries

The compiler would not be able to perform static analysis and optimizations on them

Software for HPJava

There are two main parts to the software. The HPJava development kit, hpjdk contains the HPJava compiler and an implementation of the high-level communication library, Adlib

For Distributed-memory parallel computers, one should install the second HPJava package mpiJava

Conclusion

Our experience thus far is that Java is a good choice as a base language: it is easy to extend, and its safety features greatly simplify the compiler writer’s task

HPJava will be most helpful for problems that have some degree of regularity

.

Thank You