Task 4: Semaphore

Semaphore

            A semaphore is a protected variable or abstract data type that constitutes a constitutes a classic method of controlling access by several processes to a common resource in a parallel programming environment. It generally takes one or two forms: binary and counting. A binary semaphore is a simple true and false that controls access to single resource.

There is one Pascal example is defined below

procedure V (S : Semaphore);

 begin

   (* Atomic operation: increment the semaphore. *)

   S := S + 1;

 end;

   (* Atomic operation: decrement the semaphore. *)

 procedure P (S : Semaphore);

 begin

   (* Whole operation is atomic *)

   repeat

     Wait();

   until S > 0;

   S := S - 1;

 end;

Reference

Treese, GW & Stewart, LC 2003, Designing systems for Internet commerce, 2^nd edn, Addison-Wesley, Boston, MA.

Task3: CORBA

CORBA

CORBA is Common Object Request Broker Architecture. It is standard distributed object architecture developed by the object Management Group (OMG).

CORBA object differ from typical programming language objects in these ways:

• CORBA objects can be located anywhere on a network.
• CORBA objects can interoperate with objects on other platforms.
• CORBA objects can be written in any programming language for which there is a mapping from OMG IDL to that language.

CORBA object Interface

All CORBA objects support an IDL interface. It defines as object type. An interface can inherit from one or more interface. It is very similar to Java and C++.

An IDL interface declares a set of client accessible operations, exceptions, and typed attributes (values). Each operation has a signature that defines its name, parameters, result, and exceptions. A simple IDL interface that describes the classic "Hello World" program, follows.

module HelloApp

{

  interface Hello

  {

    string sayHello();

    };

};

Reference

Krill, P (2008). Cobra language slithering to open source. Retrieved on 23/05/2010 from http://www.infoworld.com/d/developer-world/cobra-language-slithering-open-source-202

Task2: Variable and Connectivity with MySQL

Variables in PHP

      To storing the values we are using variables, like text strings, numbers and arrays. We can use variable in whole programme. The variables start with $ sign.

Example

$var_name = value;

Rules for variable

• A variable name must start with a letter or an underscore "_"
• A variable name can only contain alpha-numeric characters and underscores (a-z, A-Z, 0-9, and _ )
• A variable name should not contain spaces. If a variable name is more than one word, it should be separated with an underscore ($my_string), or with capitalization ($myString)

MySQL Database

      MySQL is database. MySQL is stored in database objects called tables. A table is a collection of related data entries and it consists of columns and rows.

MySQL Connection

      In PHP, my connection function is:

mysql_connect(servername,username,password);

Example of MySQL connection in PHP

$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

// some code
?>

Closing Connection

The connection will be closed automatically when the script ends.

$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

// some code

mysql_close($con);
?>

Reference

n.d (2010). PHP. Retrieved on 23/05/2010 from http://www.w3schools.com/php/default.asp

Task 1: PHP Introduction

PHP Introduction

1.     PHP stands for Hypertext Preprocessor

2.     It is server-side scripting language

3.     It is executed on server

4.     It supports many databases like MySQL, Oracle, Informix, Sybase, generic ODBC, etc

5.     It is an open source software

6.     It is free to download and use 

What is PHP file?

      It can contain text, HTML tags and scripts. It is returned to the file browser as plain HTML. PHP files have a file extension of “.PHP”, “.PHP3” or “.phtml”  

Why PHP?

      PHP returns on many platforms like windows, Linux, Unix. It is compatible with all servers which we are using today like apache, IIS, etc. It is easy to learn. It is easy to run on server side.

PHP syntax

      A PHP scripting always start with .

Example:

?>

Php file normally contains HTML tags, just like HTML file and some php scripting code.

Comments in PHP

There are two types of comment we r using. First is single line and multiple line comments. To use single line comment we use //. Second is multiple line comments use /* and */.

For example

//This is a comment

/*
This is
a comment
block
*/
?>

Week 10- M-commerce

M-commerce

            M-commerce is about proving services for mobile clients. It is buying and selling of goods and services through wireless handheld devices such as cellular phone. The emerging technology behind e-commerce is based on wireless application protocol. M-commerce market potentially handset manufacturer such as Nokia, Ericsson, Motorola are working with carriers such as AT&T wireless. As delivery purpose mobile device is very faster, more secure and scalable. There are lots of companies are affected by m-commerce like financial services which includes mobile banking. Telecommunications, in which service changes, bill payment and account reviews can all be conducted from the same handheld device. Service/retail, as consumers are given the ability to place and pay for orders on-the-fly. Information services, which include the delivery of financial news, sports figures and traffic updates to a single mobile device.

Reference

n.d (2000). M-commerce. Retrieved on 22/05/2010 from  http://searchmobilecomputing.techtarget.com/definition/m-commerce

Week 9- Business process modelling

Business process modelling


             It is software engineering is the activity of representing process of an entire organization. It is mainly using by analysts and managers who are improve process efficiency and quality. In this process they may not require information technology. 

Business process modelling defines in:
•  The various model elements may be joined together
•  produces a coherent picture of a named business process
•  includes the inputs, outputs, events, goals and other resources
   which are of significance (Ince D,2004)

Value-added ethical design

          Online system is very hard to maintain because e-commerce applications are growing quickly. It protects personal integrity, privacy, identity theft. Business process modelling is needed can include ethical values as a way of increasing value made by business process. Some people are still avoiding exchanging their information online. People value privacy and their personal integrity, but computerised record keeping in online databases can disturb feelings of trust in online information exchange.
Why modelling with UML
            It is easy to solve the problems with the help of algorithm description for methods. The important for the event determined processes that may exist behind fields. The holistic model of the development environment is required and this process is part of object modelling technique. Object modelling consists of set of classes. The classes define the properties and actions of the object in present life. Once class is defined, many objects of that same class can be created. But in this case not every class is related to other class. The eight main diagrams used in UML are: (Conallen,2003)

1. Use Case
2. Class
3. Sequence
4. Collaboration
5. State chart
6. Activity
7. Component
8. Deployment diagrams

References

Ince, D 2004, 'Developing distributed and e-commerce applications', 2nd edn, Addison-Wesley, Harlow, Essex, UK.

Conallen, J 2003, Building web applications with UML, 2nd edn, Addison-Wesley, Reading, MA.

Week 8- Concurrency and Transaction

Concurrency

            Concurrency is allowing simultaneous access of same data by different users. Locks useful for accessing the database are

1.       Exclusive

       The exclusive lock is useful for locking the row when an insert, update or delete is being done. This lock should not be applied when we do only select from the row.

2.       Shared lock

        We can do the table as Share Lock as many share locks can be put on the same resource. (Scoot, 2000-2009)

Transaction

            Transaction is sequence of information exchanging and related work that is treated as a unit for the purposes of satisfying a request and data integrity.  Database transaction should enforce the ACID rules.

Atomicity- all task in a transaction must happen or none of them. Transaction must be completed or must not complete.  

Consistency- transaction takes database from one consistent state to another.

Isolation- two simultaneous transactions cannot interfere with one another. Intermediate results within a transaction must remain invisible to other transaction.

Durability- Completed transactions cannot be aborted later or their results discarded.  The changes applied to the database by a committed transaction must persist in the DB. The changes must not be lost because of failure.

Reference

Scoot, W (2000-2009). Introduction to Concurrency Control. Retrieved on 22/05/2010 from http://www.agiledata.org/essays/concurrencyControl.html

Week 7-Internet Security

What is internet security?

            Security is to avoid risk. Risk is obtained when your network is connected to other network. Internet security secures your internet account and files of your computer. Internet security has become very serious issue in the world.

 Why internet security?

            To secure companies private data in the organization need security. This risk perhaps mat worse when there is no protection. Internet security, the computer's internet account and files from the computer are protected from any intrusion of any unknown users. IT security is very useful to the business users because it makes them feel secured and confident from any cyber crime. The useful programme contains hidden malicious intent such as viruses, Trojan horse, spywares and worms. To protect these malicious programmes we use security to protect our data. (Horowitz, 2009)

Network security and growth of e-commerce

            Network security provides protection at the organizations by keeping out hackers. The basic network security for user is username and password of your system. Security is necessary for the e-commerce. Now a day’s e-commerce is the heart of the business. E-business consists buying and selling of products and services. It conducted between businesses is referred to as business-to-business or B2B. It is conducted by companies such as Amazon.com. E-commerce that is conducted between business and consumers. (Ketel, 2009)

Reference

Horowitz, M (2009). The Safest Way to Protect Sensitive Computing Files. Retrieved on 21/05/2010 from

http://www.esecurityplanet.com/views/article.php/3835861/article.htm

Ketel, M (2009). E-commerce. Retrieved on 21/05/2010 from http://searchcio.techtarget.com/sDefinition/0,,sid182_gci212029,00.html

Introduction: Elevator Pitch2

These blog is defined with different topics. Firstly, it is talk about internet security. Internet security is preventing important data. Now a day it becomes major issue. Companies must have to prevent client data. This risk become worse when there is no protection. IT security is very useful to the business users because it makes them feel secured and confident from any cyber crime. Concurrency is allowing simultaneous access of same data by different users. There are two types of concurrency exclusive and shared lock. Transaction is sequence of information exchanging and related work that is treated as a unit for the purposes of satisfying a request and data integrity. Business process modelling is software engineering is the activity of representing process of an entire organization. It is mainly using by analysts and managers who are improve process efficiency and quality. Modelling with UML is easy to solve the problems with the help of algorithm description for methods. M-commerce is about proving services for mobile clients. It is buying and selling of goods and services through wireless handheld devices such as cellular phone. In workshop it contains PHP and CORBA. PHP is Hypertext Pre-processor. It is server-side scripting language. Furthermore it defines syntax, variables and how to use PHP. Database connectivity is heart of the PHP. With the help of SQL connectivity organization can easily store client data in their system. CORBA is Common Object Request Broker Architecture. It is standard distributed object architecture developed by the object Management Group (OMG). A semaphore is a protected variable or abstract data type that constitutes a constitutes a classic method of controlling access by several processes to a common resource in a parallel programming environment.