MAINFRAME COMPUTER

Tt refers to a class of ultra-reliable medium and large-scale servers designed for enterprise-class and carrier-class operations.

The first mainframe vendors were Burroughs, Control Data, GE, Honeywell, IBM, NCR, RCA and Univac, otherwise known as "IBM and the Seven Dwarfs." After GE and RCA's computer divisions were absorbed by Honeywell and Univac respectively, the mainframers were known as "IBM and the BUNCH."

The Vendors

For decades, IBM has been the dominant vendor in the mainframe business. Although many tried to compete by offering IBM-compatible mainframes, only Amdahl (Fujitsu) has remained as a competitor in this arena (see IBM-compatible mainframe). Unisys, Sun and others also make mainframe-class machines that typically run under a version of Unix or Linux.

There Is a Difference

One might wonder why mainframes cost a million dollars or more when the raw gigahertz (GHz) rating of their CPUs is not any higher than a PC costing 1,000 times less. Quite often in fact, the ratings are lower. Here are the reasons.

Lots of Processors, Memory and Channels

Mainframes support symmetric multiprocessing (SMP) with several dozen central processors in one system. They are highly scalable. CPUs can be added to a system, and systems can be added in clusters. Built with multiple ports into high-speed caches and main memory, a mainframe can address thousands of gigabytes of RAM. They connect to high-speed disk subsystems that can hold terabytes of data.

Enormous Throughput

A mainframe provides exceptional throughput by offloading its input/output processing to a peripheral channel, which is a computer itself. Mainframes can support hundreds of channels, and additional processors may act as I/O traffic cops that handle exceptions (channel busy, channel failure, etc.).

All these subsystems handle the transaction overhead, freeing the CPU to do real "data processing" such as computing balances in customer records and subtracting amounts from inventories, the purpose of the computer in the first place.

Super Reliable

Mainframe operating systems are generally rock solid because a lot of circuitry is designed to detect and correct errors. Every subsystem may be conPublish Posttinuously monitored for potential failure, in some cases even triggering a list of parts to be replaced at the next scheduled maintenance. As a result, mainframes are incredibly reliable with mean time between failure (MTBF) up to 20 years!

JAVA DATABASE

/*this program is for access database with jdbc odbc driver database1
and database with 3 fields*/

import java.awt.*;
import java.sql.*;
import javax.swing.*;
public class db{
public static void main(String[] arguments) {
PreparedStatement ps;
ResultSet rs;
int id;
String s;
Connection conn;
Statement st;
String data = "jdbc:odbc:database1";
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
conn = DriverManager.getConnection(data, "", "");
System.out.print("\nConnection successful");
s= JOptionPane.showInputDialog(null,"Enter ID : ");
id=Integer.parseInt(s);

String name= JOptionPane.showInputDialog(null,"Enter NAME : ");


s= JOptionPane.showInputDialog(null,"Enter MARK : ");
int mark=Integer.parseInt(s);

st=conn.createStatement();
ps=conn.Statement("select * from sinfo where id = "+id);
rs=st.executeQuery("select * from sinfo where id = "+id);
while(rs.next())
{
System.out.print("\n\nID : "+rs.getString(1)+"\tName : "+rs.getString(2)+"\tMarks : "+rs.getString(3));
}
rs=st.executeQuery("insert into sinfo(id,name,mark) values ("+id+", '"+name+"', "+mark+")");
}
catch(Exception e)
{
System.out.print(e);
}

}
}

GOOGLE HISTORY

Chances are, if you've ever searched for anything on the Internet, you've discovered Google.com. Chances are also, once you've discovered Google.com, yours is one of over 150 million Internet searches that Google.com handles a day. With reliable and almost instantaneous results (the life span of a Google query normally lasts less than half a second), Google claims one of the widest audiences among Web sites, with 3 billion searchable documents and more than 21 million unique users per month. A dot-com company that made it, Google Inc. has not only survived, but is making a profit. Credit is given to top-rate technology, a rare sales model and an aggressive vision for what's ahead.

Google, Inc., the developer of the award-winning Google search engine, was conceived in 1995 by Stanford University computer science graduate students, Larry Page and Sergey Brin. Their meeting at a spring gathering of new Ph. D. computer science candidates launched a friendship and later a collaboration to find a unique approach to solving one of computing's biggest challenges: retrieving relevant information from a massive set of data.

By 1996 this collaboration had produced a search engine called BackRub, named for its unique ability to analyze the "back links" that point to a given Web site. Continuing to perfect the technology in 1998, Page and Brin built their own computer housing in Larry's dorm room, a business office in Sergey's room, and Google had a new home. The next step was to find potential partners who might want to license their search technology, a technology that worked better than any available at the time. Among the contacts was David Filo, a friend and Yahoo! founder. Filo encouraged the two to grow the service themselves by starting a search engine company.

The name "Google" was chosen from the word "googol," a mathematical term coined by Milton Sirotta, nephew of American mathematician Edward Kasner, for the number represented by 1 followed by 100 zeros. A googol, or google, represented a very large number and reflected the company's mission to organize the immense, seemingly infinite, amount of information available on the World Wide Web.

Unable to secure the financial support of the major portal players of the day, cofounders Page and Brin decided to make a go of it on their own. They wrote a business plan, put their graduate studies on hold, and searched for an investor. They first approached Andy Bechtolsheim, founder of Sun Microsystems, and friend of a Stanford faculty member. Impressed with their plans, Bechtolsheim wrote a check to Google Inc. for $100,000. The check, however, preceded the incorporation of the company, which followed in 1998.

Shortly after its incorporation, Google Inc. opened its new headquarters in the garage of a friend in Menlo Park, California. Their first employee was hired--Craig Silverstein, who later became Google's Director of Technology. By this time, Google .com was answering 10,000 search queries a day. Articles about the new Web site with relevant search results appeared in USA Today and Le Monde. In December, PC Magazine named Google to its list of Top 100 Web Sites and Search Engines for 1998.

With the number of queries growing to 500,000 a day, and the number of employees growing to eight, Google moved its offices to University Avenue in Palo Alto in February 1999. With interest in the company growing as well and Google's commitment to running its servers on the Linux open source operating system, Google signed on with RedHat, its first commercial customer.

By early June, Google had secured $25 million in equity funding from two leading venture capital firms in Silicon Valley: Sequoia Capital and Kleiner Perkins Caulfield & Buyers. Staff members from the two investors joined Google's board of directors. Joining as new employees were Omid Kordestani from Netscape, who became Google's Vice President of Business Development and Sales; and UC Santa Barbara's Urs Hölzle, who became Google's Vice President of Engineering. Having again outgrown their work space, the company moved to the Googleplex , their current headquarters in Mountain View, California.

COVERING LETTER FOR RESUME

your name
your address

date

Dept. Name
Company name

Dear Sir :

I am fresher softw engg and am currently exploring job opportunities. As my resume reveals, I have a Bachelors degree in Computer Science. I have more then three years of software development experience using C++, C and Java, ASP.NET in PC based and real-time systems.

also i have sufficient knowledge of networking concepts & practical. I enjoy working in a high energy and high performance work environment. I have worked on and learned a great deal from several very interesting and complex commercial projects.I will be anxious to take on new challenges and build upon my knowledge base. I am excited by the prospect of working with an organization that is both an unquestioned leader in its programming niche and an enthusiastic risk taker in an entirely new frontier.

I have enclosed my resume for your review. I would like the opportunity to meet and share more about my qualifications and the ways in which I can contribute to the team. Thank you for your consideration.

yours sincerely

your name