In n-tier architecture the entire application is divided in several pieces. These pieces can be logical or physical. Each piece performs a specific task such as displaying user interface or data access. There can be any number of tiers or layers of such pieces. Hence, the name n-tier (Note that many times the terms tier and layer are used interchangeably). However, most commonly applications have 3 distinct tiers or layers. They are:

• Presentation Layer
• Business Logic Layer
• Data Access Layer

As you can guess, presentation layer is nothing but a piece of software that deals with user interface of your application. Displaying data to the end user and allow them to interface with it is the core functionality of this layer.

In most of the cases the data entered by the end user needs some kind of validation or further processing. This is the responsibility of Business Logic Layer.

Finally, your application data needs to be stored and retrieved in some data store (RDBMS, XML etc.). This task is handled by Data Access Layer.

In short, the process works like this:

• User requests for some application data.
• The data access layer retrieves the data and is forwarded to the presentation layer via business logic layer. Sometimes data access layer gives this data directly to presentation layer.
• Presentation layer receives the data to be displayed via business logic layer.
• The user changes the data and initiates the appropriate action (such as insert, or update).
• The business logic layer validates the data submitted by the user.
• If the data is valid it is handed over to data access layer for updating into the database.

Advantages of N-Tier ArchitectureAt first glance this division of tasks may seem to be unnecessary. However, it gives following benefits:

• The applications gets divided in logically isolated pieces reducing tight coupling between the UI, business processes and database.
• Change in the underlying database and data access methods do not have any effect on the presentation layer or client application.
• Client application no longer has SQL statements embedded in it. This makes it de-coupled from rest of the application.
• Table and column names can be effectively eliminated from the client-side code.
• The client application is unaware from where data comes (location transparency).
• It becomes easier to modify or extend your application, without breaking or recompiling the client-side code.

The downside of n-tier architecture is that you need to create many isolated classes and pieces of software. However, benefits of n-tier applications will far outweigh its disadvantage.

No.  Once the proper catch block processed, control is transferred to the finally block (if there are any).

(Refer to accomplishments. Everyone has had a few of these pressure situations in a career. Behavior-related questions aim at assessing a candidate's character, attitude, and personality traits by asking for an account of how the candidate handled certain challenging situations. Plan for such questions by making a list of the desirable traits relevant to the needs of the industry or prospective employer and by preparing some job-related stories about your experience that demonstrate a range of those traits and habits of conduct. Before answering the questions, listen carefully and ask any clarifying questions you think necessary. Tell your story and conclude by explaining what you intended your story to illustrate. Finally, ask for feedback: "Does this tell you what you need to know?")

The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media.

Actually, there can be several causes of fuzzy characters on the display. The first step in checking out this problem is to reset the display resolution to standard VGA values. If the fuzzy characters remain, check the intensity and contrast controls to see if they are out of adjustment. Finally, you might need to remove built-up electromagnetic fields from the screen through a process called degaussing. This can be done using a commercial degaussing coil. However, newer monitors have built-in degaussing circuits that can be engaged through their front panel controls. These monitors normally perform a degauss operation each time they are turned on. However, there are occurrences when the user might need to performthis operation.

When a PC is turned on, the entire system is reset to a predetermined starting condition. From this state, it begins carrying out software instructions from its BIOS program. This small programs permanently stored in the ROM memory IC located on the system board. First, the BIOS performs a series of diagnostic tests (called POST, or Power On Self Tests) on the system to verify that it is operating correctly. Next, the BIOS places starting values in the system's various programmable devices. These intelligent devices regulate the operation of different portions of the computer's hardware. This process is called initialization. Finally, the BIOS performs the bootstrap sequence where it searches the system for a special program that it can use to load other programs into RAM and start the operating system.