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7 | |
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8 | <sect1 id="pre-audience"> |
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9 | <?dbhtml filename="audience.html"?> |
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10 | |
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11 | <title>Audience</title> |
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12 | |
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13 | <para>There are many reasons why somebody would want to read this book. |
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14 | The principal reason is to install a Linux system from the source code. |
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15 | A question many people raise is, <quote>why go through all the hassle of |
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16 | manually building a Linux system from scratch when you can just download |
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17 | and install an existing one?</quote> That is a good question and is the |
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18 | impetus for this section of the book.</para> |
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19 | |
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20 | <para>One important reason for the existence of CLFS is to help people |
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21 | understand how a Linux system works. Building an CLFS system helps |
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22 | demonstrate what makes Linux tick, and how things work together and |
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23 | depend on each other. One of the best things this learning experience |
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24 | provides is the ability to customize Linux to your own |
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25 | tastes and needs.</para> |
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26 | |
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27 | <para>A key benefit of CLFS is that it allows users to have more control |
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28 | over their system without any reliance on a Linux implementation designed |
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29 | by someone else. With CLFS, <emphasis>you</emphasis> are in the driver's |
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30 | seat and dictate every aspect of the system, such as the directory layout |
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31 | and bootscript setup. You also dictate where, why, and how programs are |
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32 | installed.</para> |
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33 | |
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34 | <para>Another benefit of CLFS is the ability to create a very compact |
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35 | Linux system. When installing a regular distribution, one is often forced |
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36 | to include several programs which are probably never used. These programs |
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37 | waste disk space or CPU cycles. It is not difficult to build an CLFS |
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38 | system of less than 100 megabytes (MB), which is substantially smaller |
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39 | than the majority of existing installations. Does this still sound like a |
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40 | lot of space? A few of us have been working on creating a very small |
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41 | embedded CLFS system. We successfully built a system that was specialized |
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42 | to run the Apache web server with approximately 8MB of disk space used. |
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43 | Further stripping could bring this down to 5 MB or less. Try that with a |
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44 | regular distribution! This is only one of the many benefits of designing |
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45 | your own Linux implementation.</para> |
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46 | |
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47 | <para>We could compare Linux distributions to a hamburger purchased at |
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48 | a fast-food restaurant—you have no idea what might be in what you |
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49 | are eating. CLFS, on the other hand, does not give you a hamburger. |
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50 | Rather, CLFS provides the recipe to make the exact hamburger desired. |
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51 | This allows users to review the recipe, omit unwanted ingredients, and |
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52 | add your own ingredients to enhance the flavor of the burger. When you |
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53 | are satisfied with the recipe, move on to preparing it. It can be made |
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54 | to exact specifications—broil it, bake it, deep-fry it, or |
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55 | barbecue it.</para> |
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56 | |
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57 | <para>Another analogy that we can use is that of comparing CLFS with a |
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58 | finished house. CLFS provides the skeletal plan of a house, but it is up |
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59 | to you to build it. CLFS maintains the freedom to adjust plans throughout |
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60 | the process, customizing it to the needs and preferences of the user.</para> |
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61 | |
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62 | <para>Security is an additional advantage of a custom built Linux system. |
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63 | By compiling the entire system from source code, you are empowered to |
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64 | audit everything and apply all the security patches desired. It is no |
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65 | longer necessary to wait for somebody else to compile binary packages |
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66 | that fix a security hole. Unless you examine the patch and implement it |
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67 | yourself, you have no guarantee that the new binary package was built |
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68 | correctly and adequately fixes the problem.</para> |
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69 | |
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70 | <para>The goal of Cross Linux From Scratch is to build a complete and |
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71 | usable foundation-level system. Readers who do not wish to build their |
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72 | own Linux system from scratch may not benefit from the information in this |
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73 | book. If you only want to know what happens while the computer boots, |
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74 | we recommend the <quote>From Power Up To Bash Prompt</quote> HOWTO |
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75 | located at <ulink url="http://axiom.anu.edu.au/~okeefe/p2b/"/> or on |
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76 | The Linux Documentation Project's (TLDP) website at <ulink |
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77 | url="http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html"/>. |
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78 | The HOWTO builds a system which is similar to that of this book, but it |
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79 | focuses strictly on creating a system capable of booting to a BASH prompt. |
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80 | Consider your objective. If you wish to build a Linux system and learn |
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81 | along the way, this book is your best choice.</para> |
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82 | |
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83 | <para>There are too many good reasons to build your own CLFS system to |
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84 | list them all here. This section is only the tip of the iceberg. As |
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85 | you continue in your CLFS experience, you will find the power that |
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86 | information and knowledge truly bring.</para> |
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87 | |
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88 | </sect1> |
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