Ubuntu terminal commands

leave the GUI...use the terminal

To create a file 
touch filename.ext

To open a file
xdg-open filename.ext

To edit
gedit filename.ext

PHP Installation

For those who are looking for web designing using PHP...
Link below will take you to hassle free installation guide which will make your system ready to try out PHP codes within an hour :

LAMP server : Linux-Apache-Mysql-PHP installation

some techies who brought revolution...

*Sabeer Bhatia borned in Chandigarh, India and co-founded first free email service site Hotmail.com with Jack Smith.

*Tim Berners-Lee is the inventor of the World Wide Web and Director of the World Wide Web Consortium (W3C).

*Larry Page and Sergey Brin is co-founder of the Google internet search engine, now Google Inc.

*Charles Babbage is known as the father of computer.

*Larry Wall is the inventor of Perl, rn,patch, and many other wonderful things. He is the language designer for Perl 6, and has staked out the perl5 to perl6 translator as his own project.

*Rasmus Lerdorf is father of PHP.

*James Gosling is a famous software developer, best known as the father of the Java programming language.

*Dennis Ritchie "was" an American computer scientist notable for his influence on ALTRAN, B, BCPL, C, Multics, and Unix.

*Bjarne Stroustrup designed and implemented the C++ programming language. He is the College of Engineering Professor in Computer Science at Texas A&M University.

*Bill Gates founded Micorsoft with Paul Allen

*Michael Dell Michael Saul Dell (born February 23, 1965, in Houston, Texas) is an American businessman and the founder and CEO of Dell, Inc.

*And at last,Here is the picture of Last surviving Oldest computer
"The Witch"

B.F.H. Coleman, a lecturer in charge of digital computing at Wolverhampton College of Technology, checks a punched tape for the 1950s WITCH. The picture above was taken in1964. For more check: http://www.wired.com/gadgetlab/2009/09/britan-oldest-computer/

a short comparision between clustering ,distributed,grid and cloud computing

	distributed computing	grid computing	cluster computing	cloud computing
	Network of computer,each solving a part of problem	The grid can be thought of as a distributed system with non-interactive workloads that involve a large number of files.	clustering is the use of multiple computers, typically PCs or UNIX workstations, multiple storage devices, and redundant interconnections, to form what appears to users as a single highly available system.	the computing is "in the cloud" i.e. the processing (and the related data) is not in a specified, known or static place(s).
	Interacts by message passing	Loosely coupled system,use middle-ware, use not-in-use clock cycle of other accessible system	load balancing to acquire high performance and availability	interaction in various server in clouds where data is stored
	known physical infra structure	known geographical distribution		customers do not own the physical infrastructure.cloud computing provider provide online application to access service through s/w like web browser.

Difference Between Cluster Computing VS. Grid Computing

When two or more computers are used together to solve a problem, it is called a computer cluster . Then there are several ways of implementing the cluster, Beowulf is maybe the most known way to do it, but basically it is just cooperation between computers in order to solve a task or a problem. Cluster Computing is then just the thing you do when you use a computer cluster.

Grid computing is something similar to cluster computing, it makes use of several computers connected is some way, to solve a large problem. There is often some confusion about the difference between grid vs. cluster computing. The big difference is that a cluster is homogenous while grids are heterogeneous. The computers that are part of a grid can run different operating systems and have different hardware whereas the cluster computers all have the same hardware and OS. A grid can make use of spare computing power on a desktop computer while the machines in a cluster are dedicated to work as a single unit and nothing else. Grid are inherently distributed by its nature over a LAN, metropolitan or WAN. On the other hand, the computers in the cluster are normally contained in a single location or complex.

Another difference lies in the way resources are handled. In case of Cluster, the whole system (all nodes) behave like a single system view and resources are managed by centralized resource manager. In case of Grid, every node is autonomous i.e. it has its own resource manager and behaves like an independent entity.

Grid computing is similar to cluster computing, but there are a number of distinct differences. In a grid, there is no centralized management; computers in the grid are independently controlled, and can perform tasks unrelated to the grid at the operator's discretion. The computers in a grid are not required to have the same operating system or hardware. Grids are also usually loosely connected, often in a decentralized network, rather than contained in a single location, as computers in a cluster often are.

Grid: “super virtual computer” composed of many networked loosely coupled computers acting together to perform very large tasks.more loosely coupled, heterogeneous, and geographically dispersed. It can also be thought of as distributed and large-scale cluster computing
Grid evolution:

Inspired from all the below

- High performance computing
- Cluster computing

- Peer to Peer computing

- Internet computing

Grid characteristics:

resources that
- are connected via network
- are geographically distributed
- heterogeneous hardware
- transparent management for performance and fault tolerance
Virtual organisation
Explicit trust relationships between users and resources
Scales in time and space

Characteristics of Grid Computing

Loosely coupled (Decentralization)

Diversity and Dynamism

Distributed Job Management & scheduling

Cluster:High Performance,Massively parallel,low cost software,interconnected via high speed private networks, shared storage via nas/san. focus on parallel programmming.
High-availability (HA) clusters
Load-balancing clusters
Compute clusters

Characteristics of Cluster computing

Tightly coupled systems

Single system image

Centralized Job management & scheduling system

Cloud:The key characteristic of cloud computing is that the computing is "in the cloud" i.e. the processing (and the related data) is not in a specified, known or static place(s). This is in contrast to a model in which the processing takes place in one or more specific servers that are known. All the other concepts mentioned are supplementary or complementary to this concept.

This matter is collected from various online pages...