Operating system as magician(魔术师) The four illusions Many separate computers, one for each process < Multitasking Large memory -Virtual memory Disks and other secondary storage are organized as collections of files-"File systems Windows and menus-"Graphical User Interface(GUD)HUANG Lihua, Fudan University Operating system as magician(魔术师） • The four illusions – Many separate computers, one for each process – “Multitasking” – Large memory – “Virtual memory” – Disks and other secondary storage are organized as collections of files – “File systems” – Windows and menus – “Graphical User Interface (GUI)