Single point signon is a data security concept that if implemented, simplifies things for the user. It involves automatically sending the same password to all other applications that need user IDs and passwords when they are launched. However, single point signon is difficult to implement. One of the main reasons for this is the fast pace of change in the computer world. Today's solutions will already be outdated in a few months' time. In general, two different techniques are used for single point signon. The first is based on feeding the user ID and password, including the old password where necessary, into the keyboard buffer when an application is launched that requires them. The advantage of this method is that all the normal network loginscripts are run as normal. One disadvantage is that it easy to use up too much of the available memory in DOS. The other method uses API functions (Application Programming Interface) to authorize the user on the basis of his or her user ID and password. A disadvantage in networks is that any logon scripts, etc. are not run.