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diff --git a/build_tools/larch8/larch0/docs/html/medium.html b/build_tools/larch8/larch0/docs/html/medium.html new file mode 100644 index 0000000..fddc2b2 --- /dev/null +++ b/build_tools/larch8/larch0/docs/html/medium.html @@ -0,0 +1,178 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> + +<html> +<head> +<meta http-equiv="Content-type" content="text/html; charset=utf-8" /> +<title>Preparing the larch live medium</title> +<!-- (en) Add your meta data here --> + +<link href="css/larchdocs.css" rel="stylesheet" type="text/css"/> +<!--[if lte IE 7]> +<link href="css/yaml/core/iehacks.css" rel="stylesheet" type="text/css" /> +<![endif]--> +</head> + +<body> +<!-- skip link navigation --> +<ul id="skiplinks"> + <li><a class="skip" href="#col1">Skip to main content (Press Enter).</a></li> +</ul> + +<div class="page_margins"> + <div class="page"> + <div id="top"><div id="tm"></div></div> + <!-- begin: #col1 --> + <div id="col1" role="main"> + <div id="col1_content"> + <div id="header" role="banner"> + <h1><span><em>live Arch Linux</em> builder</span></h1> + </div> + + <!-- begin: #col3 navigation column --> + <div id="col3" role="complementary"> + <div id="col3_content"> + <img class="indent2" alt="larch logo" src="css/screen/larch150x.png" width="150" height="150" /> + <div class="vlist"> + <ul> + <li><a href="index.html"><h6>Table Of Contents</h6></a></li> + <li><a href="profiles.html"><h6>Next:</h6> + <div class="indent1">Profiles</div></a></li> + <li><a href="larchify.html"><h6>Previous:</h6> + <div class="indent1">Building the live system</div></a></li> + </ul> + </div> + </div> + </div> + <!-- end: #col3 --> + +<div class="larchdocs"> +<h2 id="pagetitle" level="1">Preparing the <em>larch live</em> medium</h2> + + +<p>The building blocks for the preparation of a <em>live</em> medium are +produced by the 'larchification' process: the <em>squashfs</em> +archive, 'system.sqf', the 'boot' directory, containing the kernel and +<em>initramfs</em>, and the modifications overlay, 'mods.sqf'. +</p> + +<p>This stage adds the bootloader files and user-defined customisations +which are directly copied to the medium rather than being included in +the overlay (essentially the stuff from the 'cd-root' directory in the +profile. See the <a href="profiles.html#cd-root">cd-root</a> section in the +profiles documentation for details on how to customise this data. On +writeable media it is also possible to specify that the medium be used +as a writeable overlay branch in the <em>aufs</em> root ('/') file-system. +Finally the system is written to +the medium, if it is a partition (USB-stick, etc.), or - in the case +of a CD/DVD - an <em>iso</em> file is created. +</p> + +<p>The structure of the <em>live</em> system is such that it is fairly +easy to transfer a <em>larch</em> system from one medium to another, +including the preservation of changes that have been made using the +data persistence facility, and including the possibility of transferring +a non-writeable system to a writeable medium and then enabling data +persistence. Support files for these operations are saved in the +'/boot/support' directory of the medium - these are mostly binary executables +which may not be available (in the correct version) on the machine used +to perform the operations. The libraries they need are also included, and the +applications must be run as +</p> +<pre> path/to/support/support application-name arguments</pre> +<p>The applications supported in this way are <em>mksquashfs</em>, <em>unsquashfs</em>, +<em>extlinux</em> and <em>syslinux</em>. +Also the binaries 'mbr.bin' and 'isolinux.bin' from the <em>syslinux</em> +package are made available here. The copying process can, however, be delegated to +the 'larch-medium' script, the source medium being specified using the '-S' +option (run 'larch-medium -h' for all options). +</p> + +<h3><a name="overlay_persist"></a>Data Persistence: The Writeable Overlay</h3> + +<p>The medium (partition) containing the <em>larch</em> system can be used +as a writeable overlay branch for the <em>live</em> system (assuming the +partition actually is writeable), causing changes made while running the +system to be preserved from one boot to the next, basically the same as +in a 'normal' linux system. The advantage this has over just installing a +normal linux system on the partition is that the bulk of the underlying +system is highly compressed, allowing smaller devices to be used than would +otherwise be possible. It is also relatively straightforward to transfer +such a system to and from non-writeable media, such as CD/DVD. +</p> + +<p>If the medium is not writeable (or if the 'nw' boot parameter is passed) +then a writeable layer is created in <em>tmpfs</em>, a memory based file-system, +allowing the system to act 'normally' (i.e. the file-system appears +writeable) while running. However any changes will be lost on shutdown. +There are situations (e.g. 'kiosk'-systems) where this behaviour can even +be an advantage. +</p> + +<h3><a name="media_scripts"></a>Command-line Scripts</h3> + +<p>The command line script for building a <em>larch live</em> is +<strong>larch-medium</strong>. Run 'larch-medium -h' to get a +usage message. +</p> + +<p>When the <em>live</em> system is installed to a partition (e.g. +USB-stick) it is possible to choose how the boot partition will be +recognized. +The options available are via UUID, partition label, partition path +(e.g. '/dev/sdb1'), or by searching for a partition +containing the file 'larch/larchboot'. See also +<a href="larch_running.html#bootparm">'Boot parameters'</a>. +</p> + +<p>The 'bootlines' file allows the boot options to be specified in an +easily parseable, bootloader independent way. The default version +is supplied in the 'larch' package (in the 'cd-root/boot0' directory), +but this will be overridden by a version supplied in the profile. +The unprocessed version is also retained in the 'boot' directory of +the created medium, for later reference. +</p> + +<p>It is possible to repeat the installation onto various media, changing +the configuration, without needing to rerun the 'larchification' stage. +The constituent <em>larch</em> files remain unchanged. +</p> + +<h3><a name="usb2bootiso"></a>Building a boot CD for a USB-stick</h3> + +<p>Older computers may not be able to boot from USB devices, so the +possibility of generating a small <em>boot iso</em> is provided. This can +be burned to CD and can be used to boot your <em>larch</em> system on a +USB-stick. On the command line this is managed by passing the '-b' option +to the <strong>larch-medium</strong> script. +As this function uses the system on the USB-stick, this needs to be +plugged in (not mounted!) and selected in the 'Partition' entry. +</p> + +<p>As the kernel and <em>initramfs</em> are now taken from the CD rather +than from the USB device, an update of the kernel on the actual <em>larch</em> +medium would require the creation of a new boot-CD. +</p> + +</div> + + + <div class="topref"><a href="#top">Top</a></div> + </div> + <!-- begin: #footer --> + <div id="footer"> + <div id="footer-content" role="contentinfo">© 2010 Michael Towers<br /> + Page layout assisted by <a href="http://www.yaml.de/">YAML</a> and + <a href="http://www.kuwata-lab.com/tenjin/">pyTenjin</a> + </div> + </div> + <!-- end: #footer --> + </div> + <!-- end: #col1 --> + <div id="bottom"><div id="bl"><div id="bm"></div></div></div> + </div> +</div> +<!-- full skiplink functionality in webkit browsers --> +<script src="css/yaml/core/js/webkit-focusfix.js" type="text/javascript"></script> +</body> +</html> |