How can a user increase the number of pseudo-ttys?What is their use?

By default, the number of pseudo-ttys is 48. The user can define as many pseudo ttys as required by him. More than 3000 pseudo ttys are supported by the system. The pseudo ttys are not associated to any physical hardware. They are used to simulate the functioning of a real tty. A user can add pseudo ttys by editing the /etc/system and adding the following lines