OPERATING SYSTEMS 1 龚玲 lgong@sjtu.edu.cn
OPERATING SYSTEMS 龚玲 lgong@sjtu.edu.cn 1
INTRO TO JAVA o Java programming language o The one we use to write our program o general-purpose o concurrent o class-based o object-oriented o Compiled to byte code of JVM
INTRO TO JAVA Java programming language The one we use to write our program general-purpose concurrent class-based object-oriented Compiled to byte code of JVM
JAVA IS PORTABLE, As long as there is a JVM compiled for that particular processor and OS Typical program,like C or C++,is compiled for a particular processor architecture and OS. ● “Write once,run everywhere！” 0 Sun's motto for Java
JAVA IS PORTABLE, As long as there is a JVM compiled for that particular processor and OS Typical program, like C or C++, is compiled for a particular processor architecture and OS. “Write once, run everywhere!” Sun’s motto for Java
FOUR COMPONENTS OF A COMPUTER SYSTEM user user user user 1 2 3 n compiler assembler text editor database system system and application programs operating system computer hardware
FOUR COMPONENTS OF A COMPUTER SYSTEM
COMPUTER SYSTEM STRUCTURE o Computer system can be divided into four components Hardware-provides basic computing resources o CPU,memory,I/O devices ·Operating system o Controls and coordinates use of hardware among various applications and users Application programs-define the ways in which the system resources are used to solve the computing problems of the users o Word processors,compilers,web browsers,database systems,video games ·Users o People,machines,other computers
COMPUTER SYSTEM STRUCTURE Computer system can be divided into four components Hardware – provides basic computing resources CPU, memory, I/O devices Operating system Controls and coordinates use of hardware among various applications and users Application programs – define the ways in which the system resources are used to solve the computing problems of the users Word processors, compilers, web browsers, database systems, video games Users People, machines, other computers