Consistency Part 1

According to the principle of consistency , system is easier to learn and use if they have similar part that expressed in the same way . In can be divided into four type of consistency which are aesthetic, functional, internal and external consistency .

And now , I would like to explain about internal and external  consistency . What is the different between this two ?

INTERNAL CONSISTENCY is a consistency with other element in the system . The most common example of this is an iOS volume slider . It is all the same in any apple product to have those similar figure and function of the volume slider .

iOs volume slider 

EXTERNAL CONSISTENCY is a consistency with other element in the environment . Example of external consistency is emergency alarm that been used by all room is just the same . Red colour , high frequency sound to alert people . It is to indicate that most of the system throughout the environment uses  similar way to represent emergency situation. External consistency play a major role to extend the value of internal consistency in various self-determining system . However , this type of consistency are difficult to achieve in all system because different system rarely observe common design standards .

Continue, Consistency Part 2