Core Applications

The Internet has connected people across the world like never before. Using their computers and smartphones, people can interact with each other for both personal and work activities. The number of applications available to users on the Internet today is too large to list. However, all that you do on the Internet is a derivative of one of the few original applications of the Internet that can be broadly categorised as Communication, Data Transfer, and Remote Access.

Communication

From its origin many years ago and continuing today, the most popular means of digital communication is electronic mail or email. Via emails, you can exchange simple text messages or attach documents, images, and videos. Emails can be sent one-to-one or one-to-many. Emails are based on the SMTP (Simple Mail Transfer Protocol), which all email servers and clients must adhere to so that emails can be sent and accessed across different servers and clients.

Every user who wants to send or receive emails must have a unique identifier. The identifier, known as the email id or email address, is in the format: user_id@domain_name. The "@" sign is now globally synonymous with an email id. Email ids can be issued by business enterprises for their employees, by educational institutes for their students, government bodies for their employees, and any other entity that would like to use email as a means of communication for their people. These entities then manage their own email servers, which are connected with all other email servers over the Internet.

There are also cloud email services, the most well-known probably being Gmail from Google. It offers the opportunity to any individual to get a personal email id, without relying on any specific entity.

The other communication mechanism is known as instant messaging. While this takes many forms, with services such as WhatsApp and Instagram, the underlying mechanism is similar. The main difference between instant messaging and email is that instant messaging is usually used for shorter messages that users generally read and respond to quickly, making it more interactive than email.

The availability of higher bandwidth and efficient compression technology allows voice and video data to be transmitted over the Internet so efficiently that people can communicate with each other on voice and video calls. Earlier, voice calls with sufficient clarity were only possible over telephone lines, and video calls needed highly specialized equipment. Today one-to-one and even group voice and video calls using just your smartphone have become commonplace.

Data Transfer

The Internet is used to transfer data across computers. While email is good enough for text and a few files, there is often a need to transfer high volumes of data from one computer to another. A protocol known as File Transfer Protocol (FTP) is implemented by most operating systems so that computers are ready to accept files from or send files to another computer having an FTP client implementing the same protocol.

Access rights are controlled and granted only to trusted computers and users. While basic FTP clients offer functionality that is largely used by people who understand technology, the same underlying protocol can also be used by regular users. For example, many companies provide cloud data storage space for users, such as Google Drive from Google or OneDrive from Microsoft. These services implement user-friendly file transfer clients, which allow files to be uploaded and downloaded from a user's computer with a simple user interface.

Remote Access

These protocols allow users to get complete access to another machine over the Internet. One of the earliest and still widely used protocols is known as Telnet. Once you get access to the remote machine, you can run all the commands on that machine as if you were sitting at that machine. Again, access rights are controlled by only trusted computers and users with remote access to any computer.

This protocol facilitates remote working, which is especially useful for system and database administrators, and software developers since the servers they need to work on are not always physically accessible or are in a different office or a public data center.

Cloud computing, which is one of the most widely used services on the Internet, uses remote access and file transfer protocols extensively.

Beyond these three categories is a whole vast range of applications used over what we know as the World Wide Web which we will cover in the next topic.