Wiley Ubuntu Linux Secrets 978-0-470-39508-0 用户手册
产品代码
978-0-470-39508-0
Chapter 1: What is Ubuntu?
5
Application Software
Windows
Management
Software
GNU
System
Utilities
Linux kernel
computer hardware
Figure 1-1:
The Linux system.
Allowing anyone to change programming code in the kernel would result in complete
chaos. Therefore, to simplify things, Linus acted as a central point for all improvement
suggestions. It was ultimately Linus’s decision whether or not to incorporate suggested
code in the kernel. This same concept is still in place with the Linux kernel code, except
instead of Linus controlling the kernel code alone, a team of developers has taken on
the task.
The kernel is primarily responsible for four main functions:
chaos. Therefore, to simplify things, Linus acted as a central point for all improvement
suggestions. It was ultimately Linus’s decision whether or not to incorporate suggested
code in the kernel. This same concept is still in place with the Linux kernel code, except
instead of Linus controlling the kernel code alone, a team of developers has taken on
the task.
The kernel is primarily responsible for four main functions:
System memory management
♦
♦
Software program management
♦
♦
Hardware management
♦
♦
Filesystem management
♦
♦
The following sections explore each of these functions in more detail.
System Memory Management
One of the primary functions of the operating system kernel is memory management.
Not only does the kernel manage the physical memory available on the server, it can also
create and manage virtual memory, or memory that does not actually exist.
It does this by using space on the hard disk, called the swap space. The kernel swaps the
contents of virtual memory locations back and forth from the swap space to the actual
physical memory. This process allows the system to think there is more memory available
than what physically exists (as shown in Figure 1-2).
Not only does the kernel manage the physical memory available on the server, it can also
create and manage virtual memory, or memory that does not actually exist.
It does this by using space on the hard disk, called the swap space. The kernel swaps the
contents of virtual memory locations back and forth from the swap space to the actual
physical memory. This process allows the system to think there is more memory available
than what physically exists (as shown in Figure 1-2).
95080c01.indd 5
3/5/09 12:15:36 AM