“UbuntuHelp:LiveCD”的版本间的差异

2009年11月17日 (二) 19:45的版本

文章出处:

https://help.ubuntu.com/community/LiveCD

点击翻译:

English

请不要直接编辑翻译本页，本页将定期与来源同步。

Introduction

Almost any Ubuntu CD can also be used as a LiveCD as well as an installer. Only the Alternate Images and sometimes the UNR lack this functionality. Windows people might be familiar with the term 'boot CD' or 'bootable CD' - a "LiveCD session" is more than a boot CD, because you get a normal desktop environment with all the normal programs. A live CD should even find your Internet connection and let you surf the Internet with Firefox. Most versions ("distributions") of Linux have this functionality on their installer CD, although Ubuntu tries to make their live CD the easiest to use. Although a LiveCD session is a good way to demo Ubuntu without making changes to a machine, a LiveCD will always be slower than a proper install running from a hard-drive, because a CD will always be physically slower than a hard drive. If you want to keep your settings when you restart your LiveCD, you can use a persistant image.

Reasons for Using a LiveCD Session

LiveCD sessions are good for:

• a quick 'demo' on a machine before installing/upgrading Ubuntu
• checking the hardware works as expected
• seeing if you like the look & feel of the distro
• preparing yourself and your unique hardware if required
• repair tasks such as
• repairing grub perhaps after (re)installing Windows
• fixing Windows problems on a machine that doesn't have a dual-boot
• anti-virus issues
• data recovery
• resizing partitions to give Ubuntu more (or less) room
• adding a new partition(s) to your hard-drive for other distros
• preparing a machine for installing Ubuntu, if you are shy of using default or automatic settings
• 'showing off' Ubuntu to people on their own machine
• using on a random computer where access is limited
• safely using a computer which you don't trust the security of.<
  >

This is particularly good if you have a usb stick or something to save your data and settings on (see ' persistent image')

Other Ways to install Ubuntu

LiveCDs are designed for people that want to use Linux on a computer for a few hours. If you want to carry a LiveCD around with you, a persistent image lets you customise your live session. If you want to use Linux on a computer for a few months, UbuntuHelp:Wubi lets you install Ubuntu inside Windows. If you want to use Linux on a computer permanently, dual-booting|WindowsDualBoot|dual-booting lets you install Window and Ubuntu side-by-side on the same computer. Because Wubi needs Windows and Ubuntu to co-operate, you have to deal with all the problems of both systems. For example, it's not easy to completely uninstall Wubi. An experienced linux user or someone with considerable technical knowledge about Windows might find it better to try Wubi in some certain circumstances where dual-booting is infeasible or inadvisable. See the Wubi guide for more information about Wubi. Dual-booting can be daunting at first, but tends to work better once you've got it set up. As you get more comfortable with Ubuntu, you can just forget about your Windows partition. Reinstalling Windows in a dual boot environment is quite tricky, so it's best to leave your Windows partition in place unless you're absolutely sure you'll never use Windows again.

How-To LiveCD Ubuntu

Preparing your LiveCD

You need to request or create an Ubuntu CD. Once you've created a live CD, you can make a live USB memory stick if you prefer. To get a free official CD (or several), use the Shipit service, which can take 12 weeks. It is always nice to have a free official CD, or a few to give away (selling them isn't really allowed). You can also get Ubuntu by downloading the Desktop Edition of Ubuntu, then making your own CD. Cheap "write once" CDs in packs of 10 or more are usually best - you'll want to burn a new CD at least once every 6 months, when new versions of Ubuntu are released. It's best to avoid DVDs, which are more expensive and fragile, and less likely to boot in older computers. You should burn your CD at the lowest speed possible, to make sure the CD is created correctly. See GettingUbuntu for more information about getting a live CD.

Using your LiveCD

Put the Ubuntu CD into the CD/DVD-drive and reboot the computer. You should see a menu with "Try Ubuntu without any change to your computer" at the top. If you don't get this menu, read the booting From the CD guide for more information.

Choose "Try Ubuntu without any change to your computer". You should get a desktop which we call a "LiveCD session". If you don't see a desktop, read the boot options for more information.

>Figure 3: The LiveCD lets you manage partitions with GPartEd.>Also see the installer icon top-left

The Firefox icon on the top panel should let you surf the internet. Other normal programs are available in the menus. After you have finished, shut the computer down and remove the CD. At this point anything you saved to the desktop or Documents folders and such will vanish - only things you saved into folders on the hard-drive will remain. This means that there won't be any trace of your personal data (e-mails, passwords etc.) left on the machine, which can be quite useful if you don't trust the Windows installation on the computer. If you have troubles getting the working desktop but if it is still not behaving then try asking for help in Launchpad or use Signpost Help, or both.

Installing Programs or Other Packages

You can install programs to a LiveCD session in the normal way, although these will be forgotten as soon as you switch the machine off. For example, you might install antivirus or data-recovery tools to fix the system installed on the computer's hard drive. Because space is limited on a LiveCD, you should limit the number of packages you install or consider using a persistent image.

Making a Customised LiveCD

If you want to make custom Ubuntu-based Live CD, you should read the LiveCD Customisation HowTo. Without even starting from an existing Ubuntu CD you can make a customised live system, see LiveCD Customisation From Scratch.

Troubles with a LiveCD

Logging in

Sometimes a LiveCD might ask you for a user-name or password. Just leave these blank and press enter (or allow it to time-out).

>'Figure 4: Just press enter to get past this, or let it time-out

Security and Updating

While linux systems are more secure than Windows, LiveCD sessions are not meant for long-term use nor for sessions lasting several days. Because LiveCDs can't easily be updated, they may well be vulnerable to security issues discovered in the months since their release. They also can't protect you against scams such as phishing. If a criminal broke in to your live session, any changes he made to your session would be reset along with everything else when you reboot, although he could make permanent changes to the computer's hard drive. A persistent image can be updated as new security issues emerge, but also lets any damage done to your computer persist across sessions.

Setting a Password

You can set a password during a LiveCD session by opening a terminal, and typing in:

$ sudo passwd ubuntu

Text-Mode Installation

If your normal installation fails without giving an error message, or if you want to install on a very limited system, you can use the text-based installer instead.

See also

• CdDvd
• Common problems booting from the CD