Java Reference
In-Depth Information
1.12
What is an assembler?
1.13
What is a high-level programming language?
1.14
What is a source program?
1.15
What is an interpreter?
1.16
What is a compiler?
1.17
What is the difference between an interpreted language and a compiled language?
The
operating system (OS)
is the most important program that runs on a computer.
The OS manages and controls a computer's activities.
Key
Point
The popular
operating systems
for general-purpose computers are Microsoft Windows, Mac
OS, and Linux. Application programs, such as a Web browser or a word processor, cannot run
unless an operating system is installed and running on the computer. Figure 1.10 shows the
interrelationship of hardware, operating system, application software, and the user.
operating system (OS)
User
Application Programs
Operating System
Hardware
F
IGURE
1.10
Users and applications access the computer's hardware via the operating system.
The major tasks of an operating system are:
Controlling and monitoring system activities
■
Allocating and assigning system resources
■
Scheduling operations
■
1.4.1 Controlling and Monitoring System Activities
Operating systems perform basic tasks, such as recognizing input from the keyboard, sending
output to the monitor, keeping track of files and folders on storage devices, and controlling
peripheral devices, such as disk drives and printers. An operating system must also ensure that
different programs and users working at the same time do not interfere with each other. In
addition, the OS is responsible for security, ensuring that unauthorized users and programs do
not access the system.
1.4.2 Allocating and Assigning System Resources
The operating system is responsible for determining what computer resources a program
needs (such as CPU time, memory space, disks, input and output devices) and for allocating
and assigning them to run the program.
