1 | <?xml version="1.0" encoding="ISO-8859-1"?> |
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2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
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3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ |
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4 | <!ENTITY % general-entities SYSTEM "../../general.ent"> |
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5 | %general-entities; |
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6 | ]> |
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7 | |
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8 | <sect1 id="ch-temp-system-choose"> |
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9 | <?dbhtml filename="choose.html"?> |
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10 | |
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11 | <title>To Boot or to Chroot?</title> |
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12 | |
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13 | <para os="a"> There are two different ways you can proceed from this point |
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14 | to build the final system. You can build a kernel, a bootloader, and |
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15 | a few other utilities, boot into the temporary system, and build the |
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16 | rest there. Alternatively, you can chroot into the temporary system.</para> |
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17 | |
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18 | <para os="b">The <command>chroot</command> (change root) program is used to enter |
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19 | a virtual environment and start a new shell whose root directory will be set |
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20 | to the CLFS partition. This is very similar to rebooting and instructing the |
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21 | kernel to mount the CLFS partition as the root partition. |
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22 | The major advantage is that <quote>chrooting</quote> allows the builder to |
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23 | continue using the host while CLFS is being built. While waiting for package |
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24 | compilation to complete, a user can switch to a different virtual console |
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25 | (VC) or X desktop and continue using the computer as normal.</para> |
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26 | |
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27 | <para os="c">Some systems cannot be built by chrooting so they must be |
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28 | booted instead. Generally, if you building for a different arch than |
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29 | the host system, you must reboot because the kernel will likely not |
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30 | support the target machine. Booting involves installing a few |
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31 | additional packages that are needed for bootup, installing |
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32 | boot-scripts, and building a miminal kernel.<!-- We also describe some |
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33 | alternative booting methods in <xref linkend="ch-boot-whatnext"/> --> |
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34 | The boot method is needed when you are building on a different |
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35 | architecture. For example, if you are building a PowerPC system from |
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36 | an x86, you can't chroot. The chroot method is for when you are |
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37 | building on the same architecture. If you are building on, and for, |
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38 | an x86 system, you can simply chroot. The rule of thumb here is if |
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39 | the architectures match and you are running the same series kernel |
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40 | you can just chroot. If you aren't running the same series kernel, or are |
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41 | wanting to run a different ABI, you will need to use the boot option.</para> |
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42 | |
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43 | <para os="d">If you are in any doubt about this, you can try the following |
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44 | commands to see if you can chroot:</para> |
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45 | |
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46 | <screen os="e"><userinput>/tools/lib/libc.so.6 |
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47 | /tools/bin/gcc -v</userinput></screen> |
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48 | |
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49 | <para os="f">If either of these commands fail, you will have to follow the boot |
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50 | method.</para> |
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51 | |
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52 | <para os="g">To chroot, you will also need a Linux Kernel-2.6.32 or greater |
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53 | (having been compiled with GCC-4.1.2 or greater). The reason for the |
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54 | kernel version requirement is that Glibc is built to generate the library |
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55 | for the smallest version of the Linux kernel expected to be supported.</para> |
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56 | |
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57 | <para os="h">To check your kernel version, run <command>cat /proc/version</command> |
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58 | - if it does not say that you are running a 2.6.32 or later Linux kernel, |
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59 | compiled with GCC 4.1.2 or later, you cannot chroot.</para> |
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60 | |
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61 | <para os="i">For the boot method, follow <xref linkend="chapter-boot"/>.</para> |
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62 | |
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63 | <para os="j">For the chroot method, follow <xref linkend="chapter-chroot"/>.</para> |
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64 | |
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65 | </sect1> |
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