MySQL Server Performance

To make things  easier for administrators.

• Minimal memory, relatively infrequent MySQL usage: my-small.cnf
• Minimal memory combined with reliance on MySQL, or larger memory for a multipurpose system: my-medium.cnf
• Large memory server dedicated primarily to MySQL: my-large.cnf
• Very large memory server completely dedicated to MySQL: my-huge.cnf

It's worth your time to review these files, if for no other reason than to gain some ideas on the optimal ratios between the various server settings.

• Connectivity
• Memory management
• Application control
• User resource control

Read More

PHP variable-related functions

• Cast a value from one type to other type:- doubleval(), intval(), strval()
• Set  type of a variable:- settype()
• Verify  the type of a variable:- is_array(), is_bool(), is_double(), is_float(), is_int(), is_integer(), is_long(), is_null(), is_numeric(), is_object(), is_real(),  is_scalar(), is_string(),gettype()
• Destroy variables:- unset()
• Get info of variables:- empty(), get_defined_vars(), isset(), print_r(), var_dump()

Read More

TCP/IP Firewall

The combined set of protocols is called the Transmission Control Protocol and Internet Protocol TCP/IPprotocol suite.

As a network administrator, it is important that you understand the nature of potential attacks on computer security. We'll briefly describe the most important types of attacks so that you can better understand precisely what the Linux IP firewall will protect you against. You should do some additional reading to ensure that you are able to protect your network against other types of attacks. Here are some of the more important methods of attack and ways of protecting yourself against them:

Unauthorized access

This simply means that people who shouldn't be allowed to use your computer services are able to connect to and use them. For example, people outside your company might try to connect to your company accounting host or to your NFS server.

There are various ways to avoid this attack by carefully specifying who can gain access through these services. You can prevent network access to all except the intended users.

A malicious person who gains access to a computer system may guess system passwords or exploit the bugs and idiosyncratic behavior of certain programs to obtain a working account on that host.

Read More

Network Security Configuration

Installed your Linux system, you should keep some basic security measures to protect your system

Firewalls, intrusion protection, encryption, data integrity, and authentication are ways of protecting against such attacks.

• A firewall prevents any direct unauthorized attempts at access.
• Intrusion detection checks the state of your system files to see if they have been tampered with by someone who has broken in.
• Encryption protects transmissions by authorized remote users, providing privacy.
• Integrity checks such as modification digests guarantee that messages and data have not been intercepted and changed or substituted en route.
• Authentication methods such as digital signatures can verify that the user claiming to send a message or access your system is actually that person.
  
  
  system is also a gateway for a private network, the system's firewall capability can effectively protect the network from outside attacks.
  
  Linux security- the ones with which every user has experience are passwords and file permissions.

Read More

Linux Software websites

 Linux Software websites

Internet Sites	Description
ftp.redhat.com	Red Hat distribution RPM packages
rpmfind.net	RPM package repository
sourceforge.net	Source Forge open source software repository and development site
freshmeat.net	New Linux software
apps.kde.com	KDE software applications
www.gnome.org	GNOME software applications

Read More

Advanced Database Techniques

PEAR DB is the database primitives shown earlier; it provides several shortcut functions for fetching result rows, as well as a unique row ID system and separate prepare/execute steps that can improve the performance of repeated queries.

$result_set = $db->query(SQL, values);

 Pass the query( ) function SQL with 
 in place of specific values, and add a second parameter consisting of 
the array of values to insert into the SQL 

When issuing the same query repeatedly, it can be more efficient to compile the query once and then execute it multiple times, using the prepare( ) , execute( ), and executeMultiple( ) methods.

$com = $db->prepare(SQL);

This returns a com query object. The execute( ) method fills in any placeholders in the query.

PEAR DB gives a lot of methods that perform a query and fetch the results in one step:  

getOne( ) , getRow( ), getCol( ), getAssoc( ), and getAll( ). 

$value-set = $db->getOne(SQL [, values ]);

Read More

php-static variables

A static variable retains its value between calls to a function but is visible only within that function.
IT declare a variable static with the static keyword.

function test_counter (  ) {
  static $counter = 0;
  $counter++;
  echo "Static counter is now $counter\n";
}
$counter = 5;
test_counter(  );
test_counter(  );
echo "Global counter is $counter\n";
Static counter is now 1
Static counter is now 2
Global counter is 5

Variables declared outside a function are global.

 That is, they can be accessed from any part of the script. By default, 

they are not available inside functions.

Read More

trade people use Google

Google is popular anywhere
Google's free online language translation service provides a knowledgeable support staff.
you can share a lot of  things With Google+ like  events,games, photos.
ITs  Find all businesses,online classifieds,advertising classifieds.Google takes a 67%
share of the U.S. search market.

Job growth is increased by this google even search job,employment,business grows with the
help of google.

Google’s Picasa Web Albums to store photos,and manage the photos very nice.
With these tools, you can create different versions of your profile .

Google Docs  store many things like  the latest doc,text files, more updates new files.

Gmail: Email from Google

Google Groups

 Google+

Google Translate

 Google News

Google Toolbar

 Google Docs

Google Finance

Picasa

Google - YouTube

 Google Checkout

Google Sites

Android Apps on Google

 

• Google Documents:- Share and add,edit documents , see them on the run with Google Docs mobile service, and take Google Notebook for web research.
• Google Spreadsheets:- Add live data to spreadsheets, and  charts and tables you can embed in web pages.
• Google Presentations:- See them on a mobile phone and save them as video.
• Gmail:- Send email to and from a mobile phone, adjust Gmail's layout with a style sheet, and a lot more
• iGoogle:- Create your own gadgets, program a screenscraper, add Flash games, and more.
• Google Calendar:- Add web content events, public calendars, and your Outlook Calendar to this application.
• Google Reader, Google Maps, Google Earth, and Google SketchUp:- the new 3D modeling software tool.
• Picasa, YouTube, and Google Video:-- customize and use these media management apps.

 

 

 

Read More

Php Operators

PHP Operators The following table lists the operators from highest to lowest precedence. Operators A !, ~, ++, --, @ Right *, /, % Left +, -, . Left <<, >> Left <, <=, >=, > Nonassociative ==, !=, ===, !== Nonassociative & Left ^ Left | Left && Left || Left ? : (conditional operator) Left =, +=, -=, *=, /=, %=, ^=, .=, &=, |=, <<=, >>= Left AND Left XOR Left OR Left

Read More

Php Networking Functions

There are many functions in php to convert or look up domain name, IP address,
protocol, and service information.

Domain name/IP address lookups and conversions

• gethostbynamel()
• gethostbyname()
• gethostbyaddr()
• ip2long()
• long2ip()

 Sockets

• fsockopen()
• pfsockopen()
• socket_get_status()
• socket_set_blocking()
• socket_set_timeout()
  
  
  DNS resource records
  
  
  • checkdnsrr()
  • getmxrr()
   

Read More