deb http://old-releases.ubuntu.com/ubuntu/ karmic mainrestricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ karmic-security mainrestricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ karmic-updates mainrestricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ karmic-proposed mainrestricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ karmic-backports mainrestricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ karmic mainrestricted universe multiverse
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deb-src http://old-releases.ubuntu.com/ubuntu/ karmic-securitymain restricted universe multiverse
deb-src http://old-releases.ubunt u.com/ubuntu/ karmic-updatesmain restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ karmic-proposedmain restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ karmic-backportsmain restricted universe multiverse
上面是有用的更新源