Answer:
Embedded Operating System.
Step-by-step explanation:
Embedded OS (also called Real Time Operating System) is designed to perform a single purpose in devices that may or may not be computers that have very little computer power and little RAM size such as washing machines, ATM, media player, automobiles, and cameras. Examples of such embedded operating system are iOS(used in Apple's mobile devices), Symbian, Palm OS and Window OS.
Since they are used in single-purpose computers, they handle and perform their tasks with so much efficiency.
Hope this helps!