Page 412 - DCAP103_Principle of operating system

Unit 14: Case Study of Linux Operating System

compiled with make. A selection of the POSIX utility programs is listed in Figure 14.2, along Notes
with a short description of each one. All Linux systems have these programs, and many more.
Figure 14.2: A Few of the Common Linux Utility Program Required by POSIX

Program Typical use
catt Concatenate multiple files to standard output
chmod Change file protection mode
cp Copy one or more files
cut Cut columns of text from a file
grep Search a file for some pattern
head Extract the first lines of a file
ls List directory
make Compile files to build a binary
mkdir Make a directory
od Octal dump a file
paste Paste columns of text into a file
pr Format a file for printing
rm Remove one or more files
rmdir Remove a directory
sort Sort a file or lines alphabetically
tail Extract the last lines of a file
tr Translate between character sets

14.1.5 Kernel Structure
In Figure 14.1, we saw the overall structure of a Linux system. Now let us zoom in and look
more closely at the kernel before examining the various parts.
Figure 14.3: Structure of the Linux Kernel

System calls

Memory Mgt Process Mgt
I/O component component component
Vitrual Singal
Virtual File System
memory handling
File
Terminals Sockets system Paging Process
thread
discipline Network block layer replacment termination
page
Genetic
creation &
products
Line I/O scheduler
Character Network Block Page CPU
device device device cache scheduling
drivers drivers drivers
Interrupts Dispatcher

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