Learning posts

A servlet is a small program that executes on a server. Just as applets dynamically extend the functionality of a web browser, servlets dynamically extend the functionality of a web server. It is helpful to understand that as useful as applets can be, they are just one half of the client/server equation. Not long after the initial release of Java, it became obvious that Java would also be useful on the server side. The result was the servlet. Thus, with the advent of the servlet, Java spanned both sides of the client/server connection.

Bytecode is a highly optimized set of instructions designed to be executed by the Java run-time system, which is called the Java Virtual Machine (JVM). The original JVM was designed as an interpreter for bytecode. Many modern languages are designed to be compiled into executable code due to performance concerns. However, the fact that a Java program is executed by the JVM helps solve the major problems associated with web-based programs.

An applet is a special kind of Java program that is designed to be transmitted over the Internet and automatically executed by a Java-compatible web browser. Furthermore, an applet is downloaded on demand, without further interaction with the user. If the user clicks a link that contains an applet, the applet will be automatically downloaded and run in the browser. Applets are intended to be small programs. They are typically used to display data provided by the server, handle user input, or provide simple functions, such as a loan calculator, that execute locally, rather than on the server. In essence, the applet allows some functionality to be moved from the server to the client.

Software Crisis In earlier days, same codes needed to be written time and again increasing the complexity and time required for development This resulted in software not being completed on time and the cost increased than expected Solution: Object Oriented Programming Software Evolution Investigation Feasibility Study Analysis Design Implementation Maintenance Investigation First step in preparation of the IS includes the preliminary study of proposed information system investigates the information needs of the users and determines the resource requirement, costs, benefits and feasibility of a proposed project 2. Feasibility Study feasibility study is an analysis of the practicality of an idea focuses on helping answer the essential question of “should we proceed with the proposed project idea?” The feasibility study is conducted in four different areas: 1. Organizational feasibility 2. Economic feasibility 3. Technical feasibility 4. Operation

Object Oriented Programming Programming paradigm that represents the concept of "objects" that have data fields (attributes that describe the object) and associated procedures known as methods Programming methodology based on objects, instead of just functions and procedures Focuses on data rather than process As individual objects can be modified without affecting other aspects of the program, it is easier for programmers to structure and organize software programs Easier to update and change programs written in object-oriented languages Simula was the first object oriented programming language Eg: C++, Java, etc. Features of OOPS Objects Referred as instance of class Basic run-time entities in an object-oriented system a person, a place, a bank account, a table of data, etc can be an object They occupy space in memory that keeps its state  Each object contains data and code to manipulate the data  Classes Blue print or prototype  which defi

BIOS stands for Basic Input Output System. It is is kind of OS pre- attached in the system Design to detect every I/O devices It holds basic drivers -checks all I/O devices -Loads main OS -Responsible for starting System switched on manufactured by AMI,Phonix,award,Baiostar POST error test, boots trap load, BIOS is unintrusive system. CMOS and BIOS are two different components of the motherboard. CMOS work as storage if BIOS. A basic software program containing all BIOS is permanently stored in the ROM. every essencial holds program Tresh passing without knowinig is called intrusive.

PGA reffered as pin grid array in which pins of CPU are lined up in a straight format. SPGA referred as staggered pin grid array. in which pins of CPU are arranged staggered format. LGA reffered to as Land Grid Array in which pins are available within inside the socket but not in the CPU in other words in line grid array, in CPU ther are no pinsbut insteadpins areattached with in a socket which contact with with the CPU. for e.g. LGA775 socket(no pins on cpu) has better cooling system. better contact and better locking(climbing). LGA1155: Letest generation I socket, also reffered as sandy bridge, Turbo boost overclocking. More resent than LGA 1156 socket. LGA1156: ability to north bridge Doul channel DDR3 optional integreted graphics PCI express LGA1366: hi end core i series socket integreted tiple channal memmory controller external control bridge(HUB) Upgrading CPU: need to check its core suppert check multiprocessor supports or not check on the