Monitoring System Performance

Using top

To view the top CPU processes-the ones that use most of the CPU time-you can employ the top program. To start this program, type top in a terminal window (or text console). The top program then displays a text screen listing the current processes, arranged in the order of CPU usage, along with other information, such as memory and swap-space usage. Figure 20-3 shows typical output from the top program.

Figure 20-3: Viewing top CPU Processes.

The top utility updates the display every 5 seconds. You can keep top running in a window so that you can continually monitor the status of your Linux system. You quit top by pressing q or Ctrl-C or by closing the terminal window.

The first six lines of the output screen provide summary information about the system. Here is what these six lines show:

1. The first line shows the current time, how long the system has been up, how many users are logged in, and three load averages (the average number of processes ready to run during the last 1, 5, and 15 minutes).

2. The second line lists the total number of processes and the status of these processes.

3. The third line shows CPU usage-what percentage of CPU time user processes employ, what percentage of CPU time system (kernel) processes employ, and what percentage of time the CPU is idle.

4. The fourth and fifth lines show how the physical memory is used-the total amount, how much is used, how much is free, how much is shared, and how much is allocated to buffers (for reading from disk, for instance).

5. The sixth line shows how the virtual memory (or swap space) is used-the total amount of swap space, how much is used, how much is free, and how much is cached.

The following table the summary data lists information about the current processes arranged in decreasing order of CPU time usage. Table 20-9 summarizes the meanings of the column headings in the table that top displays.

Secret

You should also know that you can use combinations of other Linux commands to find the processes that are consuming the most system resources. For example, to find the top five processes that are using the most resources, type the following command line:

ps -A -o sz,cmd | sort -bgr | head -5

That command line uses ps with appropriate options to display all processes and their size, sort to sort them in decreasing numerical order of size, and finally, use head to display the first five lines of output. Here is typical output from this command line on my system:

15000 nautilus --no-default-window --sm-client-id default3
11849 /usr/X11R6/bin/X :0 -auth /var/gdm/:0.Xauth vt7
 6098 /usr/bin/python /usr/bin/rhn-applet-gui --sm-client-id default5
 5306 gnome-panel --sm-client-id default2
 5042 gnome-terminal

Using the GNOME System Monitor

Like the text-mode top utility, the GNOME System Monitor tool also enables you to view the system load in terms of the number of processes currently running, their memory usage, and the free disk space on your system. To run this tool, select Main Menu>System Tools>System Monitor. The System Monitor starts and displays its output in a window (Figure 20-4).

Figure 20-4: Viewing Current Processes in the System Monitor.

The output is similar to the output you see when you type top in a text-mode console or terminal window. In fact, the column headings in the table match what the top utility uses in its output. (See Table 20-9 for the meaning of the column headings.) As with the text-mode top utility, the display is continuously updated to reflect the current state of the system.

You can click the columns to sort the processes in different ways. You can use the drop-down list on the upper-right corner of the window to select which processes you want to see. Figure 20-4 shows a list of processes sorted in descending order of their memory usage. For each process, the GNOME System Monitor shows a number of details including the process ID (PID), the user who starts the process, and the command used to start the process.

The GNOME System Monitor window has another tab that displays the CPU and memory usage history and the free space on the file system. To view this information, click the System Monitor tab. Figure 20-5 shows the typical graphical output in the System Monitor tab. You will find the plots easy to understand. At the bottom of the tab, you see the amount of free and used space on the file systems.

Figure 20-5: Graphical Display of CPU and Memory Usage History.

Using the vmstat Utility

You can get summary information about the overall system usage with the vmstat utility. To view system-usage information averaged over 5-second intervals, type the following command (the second argument indicates the total number of lines of output vmstat should display):

vmstat 5 8
   procs                      memory    swap          io     system         cpu
 r  b  w   swpd   free   buff  cache  si  so    bi    bo   in    cs  us  sy  id
 1  0  0  46100   5304   2740  12572   0   0     2     5   11     9  10   5   7
 0  0  0  46100   5304   2748  12572   0   0     0     6  104    69   3   5  92
 0  0  0  46100   5304   2756  12572   0   0     0     5  103    71   4   6  91
 1  0  0  46100   5304   2764  12572   0   0     0     3  104    62   3   6  91
 1  0  0  46100   5304   2772  12572   0   0     0     3  103    63   2   4  94
 0  0  0  46100   5304   2780  12572   0   0     0     3  104    69   2   7  91
 0  0  0  46100   5300   2788  12572   0   0     0     3  103    64   2   7  91
 1  0  0  46100   5292   2796  12572   0   0     0     6  104    66   2   3  94

The tabular output is grouped into six categories of information, as the fields in the first line of output indicate. The second line shows further details for each of the six major fields. You can interpret the six major fields, as well as the detailed fields in each category, using Table 20-10.

The first line of vmstat output following the two header lines shows the averages since the last reboot. After that, vmstat displays the 5-second average data seven more times over the next 35 seconds. In the vmstat utility's output, high values in the si and so fields indicate too much swapping. High numbers in the bi and bo fields indicate too much disk activity.

Checking Disk Performance and Disk Usage

Red Hat Linux comes with the /sbin/hdparm program, which you can use to control IDE or ATAPI hard disks common on most PCs. One feature of the hdparm program is that the -t option enables you to determine the rate at which data can be read from the disk into a buffer in memory. For example, here's the result of the command on my system:

/sbin/hdparm -t /dev/hda

/dev/hda:
 Timing buffered disk reads:  64 MB in 3.05 seconds =  21.00 MB/sec

As you can see, the command requires the IDE drive's device name (/dev/hda) as an argument. If you have an IDE hard disk, you can try this command to see how fast data can be read from your system's disk drive.

To display the space available in the currently mounted file systems, use the df command. If you want a more human-readable output from df, type the following command:

df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/hda5             7.1G  2.6G  4.2G  38% /
/dev/hda3              99M  8.6M   86M  10% /boot
none                  125M     0  125M   0% /dev/shm

As this example shows, the -h option causes the df command to show the sizes in gigabytes (G) and megabytes (M).

To check the disk space a specific directory uses, employ the du command. You can specify the -h option to view the output in kilobytes (k) and megabytes (M), as shown in the following example:

du -h /var/log
4.0K    /var/log/vbox
20M     /var/log/cups
4.0K    /var/log/samba
4.0K    /var/log/news/OLD
8.0K    /var/log/news
12K     /var/log/httpd
4.0K    /var/log/squid
532K    /var/log/gdm
23M     /var/log

The du command displays the disk space each directory uses, and the last line shows the total disk space that directory uses. If you want to see only the total space a directory uses, use the -s option, like this:

du -sh /var
71M     /var

This says that the /var directory uses 71M of disk space.

Exploring the /proc File System

You can find out a great deal about your Linux system by consulting the contents of a special file system known as /proc. Knowing about the /proc file system is useful because it can help you monitor a wide variety of information about your system. In fact, you can even change kernel parameters through the /proc file system and thereby modify the system's behavior.

The /proc file system is not a real directory on the disk but a collection of data structures in memory, managed by the Linux kernel, that appears to the user as a set of directories and files. The purpose of /proc (also called the process file system) is to enable users to access information about the Linux kernel and the processes currently running on your system.

You can access the /proc file system just as you access any other directory, but you have to know the meaning of various files to interpret the information. Typically, you can use the cat or more command to view the contents of a file in /proc; the file's contents provide information about some aspect of the system.

As with any directory, you may want to start by looking at a detailed directory listing of /proc. To do so, type ls -l /proc. In the output, the first set of directories (indicated by the letter d at the beginning of the line) represents the processes currently running on your system. Each directory that corresponds to a process has the process ID (a number) as its name.

Several files and directories in /proc contain interesting information about your Linux system. The /proc/cpuinfo file, for example, lists the key characteristics of your system, such as processor type and floating-point processor information. You can view the processor information by typing cat /proc/cpuinfo. For example, here is what I get when I type the command on my system:

cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Mobile Intel(R) Celeron(R) CPU 1.50GHz
stepping        : 7
cpu MHz         : 1495.631
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
bogomips        : 2981.88

This output is from a 1.4GHz Intel Celeron system. The listing shows many interesting characteristics of the processor. Notice the line that starts with fdiv_bug. Remember the infamous Pentium floating-point-division bug? The bug is in an instruction called fdiv (for floating-point division). Thus, the fdiv_bug line indicates whether or not this particular Pentium has the bug (fortunately, my system's processor does not).

Table 20-11 summarizes some of the files in the /proc file system from which you can get information about your Linux system. You can view some of these files on your system to see what they contain. Note that not all the files shown in Table 20-11 are present on your system-the contents of the /proc file system depend on the kernel configuration and the driver modules loaded (which, in turn, depend on your PC's hardware configuration).

Using sysctl to View and Set Kernel Parameters

As the entry for /proc/sys in Table 20-11 explains, you can change kernel parameters by writing to files in the /proc/sys directory. This is one way to tune the system's performance. Red Hat Linux also comes with the /sbin/sysctl program that enables you to read and write kernel parameters without having to overwrite files manually in the /proc/sys directory.

In Chapter 13, you encounter an instruction that asks you to log in as root and enable IP forwarding in the kernel by typing the following command:

echo "1" > /proc/sys/net/ipv4/ip_forward

This is the manual way to set the value of a parameter-using the echo command to copy the value into a file in the /proc/sys directory.

You can perform this same step by running sysctl as follows:

/sbin/sysctl -w net.ipv4.ip_forward=1
net.ipv4.ip_forward = 1

This sysctl command sets the value of the parameter and echoes the new value for your information. As you can see, you refer to the parameter by using the last part of the pathname excluding /proc/sys, but you use periods (.) instead of slashes (/) as separators. Note that, if you prefer, you can continue to use slashes as separators and can refer to this variable as net/ipv4/ip_forward.

You can use sysctl to both query and set the value of a parameter. To see the value of a parameter, use the parameter's name as an argument like this:

/sbin/sysctl dev.cdrom.info

The command /sbin/sysctl dev.cdrom.info displays the contents of that parameter. In this case, dev.cdrom.info is a structure that contains many different fields; sysctl shows these fields as separate lines in the output.

For a simple parameter, such as fs.file-max, sysctl displays the single value as shown in the following example:

/sbin/sysctl fs.file-max
fs.file-max = 26163

The fs.file-max variable denotes the maximum number of file handles the Linux kernel can allocate. If you get error messages about running out of file handles, you may want to increase this value with a command, such as /sbin/sysctl -w fs.file-max=65535.

Secret

To use sysctl to modify kernel variables and tune the kernel's performance, you need to know what each parameter means. You can find some documentation on these parameters in the /usr/src/linux*/Documentation/sysctl directory of your system (provided you install the kernel-source RPM). In particular, look at the /usr/src/linux*/Documentation/sysctl/kernel.txt file for information on the kernel parameters.

You can see the values of all parameters in the /proc/sys directory by typing the /sbin/sysctl -a command. It's instructive to look through the names of the parameters and their values. You should try the /sbin/sysctl -a command on your system. Table 20-12 lists some of these parameters.

Before you use sysctl to change any of the parameters listed in Table 20-12, you should know that changing some kernel parameters can adversely affect your system's performance and even cause the system to hang. You should play with these parameters only if you know what you are doing. In particular, never play around with kernel parameters on a production system.

If you have a number of parameters to alter using sysctl, you can place the parameters and their values in a file and use the command /sbin/sysctl -p filename to load the settings from that file. For example, when Red Hat Linux boots, a startup script sets some parameters with the following command:

/sbin/sysctl -p /etc/sysctl.conf

On my Red Hat Linux system, the /etc/sysctl.conf file contains the following lines:

# Disables packet forwarding
net.ipv4.ip_forward = 0
# Enables source route verification
net.ipv4.conf.all.rp_filter = 1
# Disables automatic defragmentation (needed for masquerading)
net.ipv4.ip_always_defrag = 0
# Disables the magic-sysrq key
kernel.sysrq = 0
# Appends the PID to the core filename during core dumps
kernel.core_uses_pid = 1

Table 20-12 describes some of the interesting kernel parameters from the /proc/sys directory, as well as the meaning of these parameters.

Table 20-12: Some Kernel Parameters in the /proc/sys Directory

Parameter Name	Meaning
fs.file-max	Maximum number of file handles the Linux kernel can allocate
fs.file-nr	Three values representing the number of allocated file handles, the number of used file handles, and the maximum number of file handles
fs.super-max	Maximum number of superblocks, and thus the maximum number of mounted file systems the kernel can support (default value is 256)
kernel.acct	Three values specifying high, low, and frequency that control the logging of process accounting information-when free space on file system goes below the low (percent), accounting is suspended; it resumes when free space goes above high (percent), and frequency specifies how many seconds the free space information is valid (default values are 4% for high, 2% for low, and 30 seconds for frequency)
kernel.ctrl-alt-del	When set to 0, a Ctrl-Alt-Del keypress is handled by using the init program to restart the system; when set to 1, Ctrl-Alt-Del performs an immediate reboot without even saving any dirty buffers to the disk
kernel.domainname	The NIS domain name of the system
kernel.hostname	The hostname of the system
kernel.modprobe	Name of the program that the kernel uses to load one or more modules (for example, /sbin/modprobe)
kernel.osrelease	The version number of the operating system (for example, 2.4.20-2.48 )
kernel.ostype	Name of operating system (for example, Linux for all Linux systems)
kernel.panic	Number of seconds the kernel waits before rebooting in case of a panic (default is 0)
kernel.printk	Values that affect the printing or logging of error messages by the kernel
kernel.rtsig-max	Maximum number of POSIX real-time signals that can be outstanding in the system (default is 1024)
kernel.rtsig-nr	Number of real-time signals currently queued
kernel.shmall	Total amount, in bytes, of shared memory segments that can be created (default is 33554432 bytes)
kernel.shmmax	Maximum size, in bytes, of shared memory segments that can be created (default is 33554432 bytes; kernel supports shared memory segments up to 1GB)
kernel.sysrq	When set to 0, the SysRq key is disabled; when set to 1, user can perform specific tasks by pressing Alt-SysRq and a command key (see the file /usr/src/linux*/ Documentation/sysrq.txt for more information)
kernel.version	The build number and the date the kernel was built (for example, #1 Thu Feb 13 11:52:55 EST 2003)
net.core.netdev_max_backlog	Maximum number of packets that can be queued on input when a network interface receives packets faster than the kernel can process them (default is 300)
net.core.optmem_max	Maximum size of ancillary buffer allowed per socket (default is 10240 bytes, or 10K)
net.core.rmem_default	Default size of socket receive buffer in bytes (default is 65535 bytes, or 64K)
net.core.rmem_max	Maximum size of socket receive buffer in bytes (default is 65535 bytes, or 64K)
net.core.wmem_default	Default size of socket send buffer in bytes (default is 65535 bytes, or 64K)
net.core.wmem_max	Maximum size of socket send buffer in bytes (default is 65535 bytes, or 64K)
net.ipv4.conf.all.accept_redirects	When set to 1, the kernel accepts ICMP redirect messages (should be set to 0 for a system configured as a router)
net.ipv4.conf.all.accept_source_route	When set to 1, accepts source routed packets (should be set to 1 for a system configured as a router)
net.ipv4.conf.all.forwarding	When set to 1, enables IP forwarding for all interfaces
net.ipv4.conf.all.hidden	When set to 1, hides network addresses from other systems
net.ipv4.conf.all.log_martians	When set to 1, logs all packets with source addresses with no known route
net.ipv4.conf.all.rp_filter	When set to 0, turns off source validation; when set to 1, performs source validation using reverse path (as specified in RFC 1812)
net.ipv4.conf.all.secure_redirects	When set to 1, accepts ICMP redirect messages only for gateways listed in default gateway list
net.ipv4.conf.all.send_redirects	When set to 1, sends ICMP redirect messages to other hosts
net.ipv4.conf.all.shared_media	When set to 1, assumes that different subnets share the media and can communicate directly
net.ipv4.conf.eth0.accept_redirects	When set to 1, accepts ICMP redirect messages (must be 0 for a system used as a router)
net.ipv4.conf.eth0.forwarding	When set to 1, turns on IP forwarding for the eth0 network interface
net.ipv4.conf.eth0.hidden	When set to 1, keeps the address hidden from other devices
net.ipv4.conf.eth0.log_martians	When set to 1, logs packets with impossible addresses in the log file
net.ipv4.conf.eth0.rp_filter	When set to 0, turns off source validation; when set to 1, performs source validation using reverse path (as specified in RFC 1812)
net.ipv4.icmp_echo_ignore_all	When set to 1, kernel ignores all ICMP ECHO requests sent to it
net.ipv4.icmp_echo_ignore_broadcasts	When set to 1, kernel ignores all ICMP ECHO requests sent to broadcast or multicast addresses
net.ipv4.ip_always_defrag	When set to 1, automatically reassembles all fragmented packets (this is enabled when masquerading is enabled)
net.ipv4.ip_autoconfig	Contains 1 if the host receives its IP address by using a mechanism such as RARP, BOOTP, or DHCP; otherwise, it is 0
net.ipv4.ip_default_ttl	Time-to-live (TTL) for IP packets (default value is 64; this is the maximum number of routers through which the packet can travel)
net.ipv4.ip_forward	When set to 1, packets are forwarded among interfaces
net.ipv4.ip_local_port_range	Two numbers denoting the range of port numbers used by TCP and UDP for the local port (default range 1024-4999; you can change this to 32768-61000 if you need more ports)
net.ipv4.ip_masq_debug	When set to 1, enables debugging of IP masquerading
net.ipv4.ipfrag_high_thresh	Maximum memory for use in reassembling IP fragments (default is 262144 bytes)
net.ipv4.ipfrag_low_thresh	When maximum amount of memory (net.ipv4.ipfrag_high_thresh) is already being used to reassemble fragmented IP packets, further packets are discarded until the memory usage comes down to this value (default is 196608 bytes)
net.ipv4.ipfrag_time	Time in seconds to keep an IP fragment in memory (default is 30 seconds)
net.ipv4.tcp_fin_timeout	Number of seconds to wait for a final FIN before the socket is closed-this occurs to prevent denial-of-service attacks (default is 180 seconds)
net.ipv4.tcp_keepalive_probes	Number of keepalive probes TCP sends out before it decides that the connection is broken (default value is 9)
net.ipv4.tcp_keepalive_time	Time in seconds between keepalive messages (default is 7200 seconds, or two hours)
net.ipv4.tcp_max_ka_probes	Maximum number of keepalive probes to s BackCover Red Hat Linux 9 Professional Secrets Introduction Conventions Used in This Book About the Companion CD-ROMs Reach Out Acknowledgments Part I: Setting Up Red Hat Linux Chapter 1: An Overview of Red Hat Linux What Is Red Hat Linux? Linux as a UNIX Platform Linux Desktop Linux Networking Linux System Administration Windows and Linux Software Development in Linux Linux as an Internet On-Ramp Summary Chapter 2: Red Hat Linux Installation Understanding the Red Hat Linux Installation Process Preparing Your PC for Linux Installation Booting the Red Hat Linux Installer Installing from the Red Hat Linux CD-ROM Troubleshooting the Installation Using Boot Commands during Installation Learning Other Installation Methods Using kickstart Installation Installing Red Hat Linux on a Laptop Summary Chapter 3: 3X Window System Setup Understanding Video Cards and Monitors Understanding the X Window System Setting up X on Red Hat Linux Running X Summary Chapter 4: Printer Setup Configuring CUPS Print Queues Learning the Printing Commands Understanding the CUPS Printing System Summary Chapter 5: Sound Setup Sound Cards Supported by Red Hat Linux Configuring the Sound Card Learning Sound Device Names Testing the Sound Card Playing Audio CD-ROMs Troubleshooting Sound Cards Summary Chapter 6: Network Setup Networking Basics TCP/IP and the Internet TCP/IP Services and Client/Server Architecture TCP/IP Setup in Linux TCP/IP Network Diagnostics Summary Part II: Exploring Red Hat Linux Chapter 7: Red Hat Linux Basics Starting Red Hat Linux for the First Time Looking up Online Documentation Understanding the Linux File System Using the Nautilus Shell Navigating the File System with Linux Commands Learning the Bash Shell Summary Chapter 8: GNU Utilities An Overview of GNU Software Shell Utilities File Utilities and the find Command Text Utilities Binary Utilities Other Utilities Stream Editor - sed Summary Chapter 9: GUI Desktops Setting up a Graphical Login Using GNOME Using KDE Summary Chapter 10: Red Hat Linux Applications and Utilities Applications on the Companion CD-ROMs Editors Office Tools Graphics and Images Summary Chapter 11: Text Processing Text Editing with ed and vi Working with GNU Emacs Writing Man Pages with groff Preparing Documentation with DocBook Summary Chapter 12: Basic System Administration Revisiting Linux System Administration Becoming root Managing User Accounts Exploring the Start Here Window Managing the File System Using mtools Summary Part III: Internetworking with Red Hat Linux Chapter 13: Internet Connection Setup Deciding How to Connect to the Internet Setting Up IEEE 802.11b Wireless Ethernet Networks Learning the Basics of Dial-Up Networking Using IP Masquerading to Share an Internet Connection Setting Up a PPP Server Summary Chapter 14: Web Server Discovering the World Wide Web Surfing the Net Setting Up the Apache Web Server Using Java Servlets with Apache Creating a Secure Server with SSL Summary Chapter 15: Mail Server Installing Mail Software Understanding Electronic Mail Using sendmail Summary Chapter 16: News Server Using Simple News Strategies Installing News Software Understanding Newsgroups Configuring and Starting the INN Server Setting Up Local Newsgroups Summary Chapter 17: FTP Server Installing FTP Software Understanding FTP Configuring the FTP Server Setting up Secure Anonymous FTP Summary Chapter 18: DNS and NIS Using the Domain Name System (DNS) Using Network Information Service (NIS) Summary Chapter 19: Samba and NFS Sharing Files with NFS Setting Up a Windows Server Using Samba Summary Part IV: Managing Red Hat Linux Chapter 20: Advanced System Administration Understanding How Red Hat Linux Boots Scheduling Jobs in Red Hat Linux Backing Up and Restoring Files Managing Devices Monitoring System Performance Summary Chapter 21: Software Installation and Update Working with the Red Hat Package Manager Building Software Packages from Source Files Installing SRPMS Upgrading Red Hat Linux with the Update Agent Upgrading and Customizing the Linux Kernel Summary Chapter 22: System and Network Security Establishing a Security Framework Securing Red Hat Linux Securing the Host Securing the Network Performing Security Audits Keeping up with Security News and Updates Summary Part V: Programming Red Hat Linux Chapter 23: Software Development in Linux Software Development Tools in Linux The GNU Debugger Implications of GNU Licenses Version Control Linux Programming Topics Summary Chapter 24: Shell and Perl Scripting Looking at Some Shell Scripts Learning the Basics of Shell Scripting in Bash Perl as a Scripting Language Summary Chapter 25: Tcl/Tk Scripting Introducing Tcl Introducing Tk Summary Chapter 26: Java Programming Getting Ready for Java Programming Writing Your First Java Program Learning Java Writing GUI Applications in Java Writing Java Servlets Becoming Proficient in Java Summary Part VI: Appendixes Appendix A: Linux Commands apropos bg cal cat cd chattr chgrp chmod chown chsh compress cp cpio cut date dd df diff du expand fdformat fdisk fg file find fold free fsck grep groups gunzip gzip halt id info kill ldd less ln locate lpr ls lsof man mkdir mkfs mknod mkswap more mount mv nice nl passwd paste patch printenv ps pstree pwd reboot rm rmdir sed shutdown sort split su swapoff swapon sync tac tail tar top touch tr tty type umount unalias uname uncompress uniq wc whatis whereis which zcat, zless, zmore Appendix B: Disk Drives Disk Drive Concepts Floppy Disks in Linux Hard Disk Operations in Linux SCSI Disk Controllers and Linux Appendix C: CD-ROM Drives Supported CD-ROM Drives CD-ROM Troubleshooting Appendix D: Ethernet Cards Supported Ethernet Cards Ethernet Driver Modules Ethernet Autoprobing Multiple Ethernet Cards Appendix E: Modems and Terminals Modems Linux and Modems Setting up Linux for Dial-In Terminals and Multiport Serial Boards Appendix F: PC Cards PCMCIA Card Services for Linux Appendix G: Linux Resources Newsgroups FTP Archive Sites Magazines Appendix H: About the CD-ROMs System Requirements CD-ROM Installation Instructions What's on the CD-ROMs Source Code Coupon Troubleshooting List of Figures List of Tables List of Code Examples List of Sidebars Remember the name: eTutorials.org Copyright eTutorials.org 2008-2023. 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