First Things of Computer world

First Email Message

Ray Tomlinson

The first email was sent by Ray Tomlinson to himself in 1971. "The test messages were entirely forgettable. . . . Most likely the first message was QWERTYIOP or something similar," he said.

First Domain 

The first domain registered in 15-March 1985 named symbolics.com

Which is better between LCD screen and LED Screen

The differences between LED and LCD TV to a consumer as well as from the technical point of view are as follows:-
1. The viewing angle of LCD TV is less than that of LED TVs. LCD TVs are best viewed directly from in front and at the same plane as the screen i.e. a good view is not possible if viewed from the sides or from above or below the TV screen. LED TVs, on the other hand, has greater viewing angle.

2. LCD TVs can not be viewed under bright environment whereas LED TVs can be viewed even under direct sunlight. This is so because, the screen of LCD TVs made up of liquid crystals which changes color on passing current though it. Unlike LCD TVs, LED TV screens are made up of Light Emitting Diodes. Therefore, each tiny dot of light (pixel) on LED TV screen is like a light bulb and its glow is visible even under direct sunlight. For example, LCD TVs have the same screens as mobile phones and is not clearly visible under bright sunlight. You must have noticed that some mobile phones have light (a mobile torch).This torch is made up of an LED and thousands of such 'torch' form the LED TV screen.

Working With Document Versions

When you store a version of your document using the versions feature, you can access previous versions, delete any of the versions stored with your document, and recover document versions to a new file.

To view a version of your document
1. Select Versions… from the File menu
2. In the Versions dialog box, highlight the version you would like to open
3. Click Open

Captcha Using PHP

CAPTCHA  which stands for “Completely Automated Public Turing test to tell Computers and Humans Apart” is a type o f challenge-response test to ensure that the response is only generated by humans and not by a computer.

In simple words, CAPTCHA is the word verification test that you will come across the end of a sign-up form while signing up for Gmail or Yahoo account. The following image shows the typical samples of CAPTCHA.

You can make captcha using PHP. Here I am making number captcha which is achieved by an image. This image text is dynamically create by php and stored in session. A user can verify whether valid captcha has been entered or not.

Save this code in named captch.php

<?php 

session_start(); 

$text = rand(10000,99999); 

$_SESSION["vercode"] = $text; 

$height = 25; 

$width = 65;