使用unetbootin工具制作的liveusb，/pool/main/l/linux-lts-saucy/udeb包的名字由于过长被更改成ude了，在安装的过程中会报缺udeb包的错误。这是工具的问题，所以可以挂载光盘后，手动复制过去。
还一个比较好用的工具是usb-creator-gtk，好像就是传说中的startup disk creator。使用ubuntu 12.04.4的官方iso开始进行liveusb制作。不过按照下面方法造出来的liveusb在部分机器上会卡住不能继续安装，原因未知！
sudo mount /dev/sdc1 /mnt/sdc1
cd /mnt/sdc1/syslinux && sudo mv isolinux.bin syslinux.bin
sudo vim /mnt/sdc1/syslinux/syslinux.cfg
把超时时间timeout改成30，就是3秒的意思
sudo vim /mnt/sdc1/syslinux/txt.cfg
修改append后面的内容
append initrd=/install/initrd.gz file=/cdrom/ks.seed boot=install debian-installer/locale=en_US console-setup/ask_detect=false keyboard-configuration/layoutcode=us automatic-ubiquity quiet splash --
制作ks.seed文件
sudo vim /mnt/sdc1/ks.seed
# ubuntu preseed file
d-i debian-installer/locale string en_US
d-i debian-installer/language string en
d-i debian-installer/country string china
d-i localechooser/supported-locales multiselect en_US.UTF-8, zh_CN.UTF-8
#keyboard
d-i console-setup/ask_detect boolean false
d-i console-configuration/layoutcode string us
d-i keyboard-configuration/modelcode string SKIP
#clock
d-i clock-setup/utc boolean false
d-i time/zone string Asia/Shanghai
#network
d-i netcfg/choose_interface select auto
d-i netcfg/dhcp_failed note
d-i netcfg/dhcp_options select Do not configure the network at this time
d-i netcfg/get_hostname string test
d-i netcfg/get_domain string test-domain
d-i netcfg/wireless_wep string
# Mirror
d-i mirror/protocol string http
d-i mirror/country string china
d-i mirror/http/hostname string mirrors.163.com
d-i mirror/http/directory string /ubuntu
d-i mirror/http/proxy string
# clock
d-i clock-setup/ntp boolean true
# partition
d-i partman-auto/disk string /dev/sda
d-i partman-auto/method string regular
d-i partman-lvm/device_remove_lvm boolean true
d-i partman-md/device_remove_md boolean true
d-i partman-auto/choose_recipe select atomic
d-i partman/default_filesystem string ext4
d-i partman/confirm_write_new_label boolean true
d-i partman/choose_partition select Finish partitioning and write changes to disk
d-i partman/confirm boolean true
#user
#d-i passwd/root-login boolean true
#d-i passwd/root-password-crypted password $1$3nGno0$c4rp7NcQRAcJV3AdzKV890
#d-i passwd/make-user boolean true
d-i passwd/user-fullname string ubuntu
d-i passwd/username string ubuntu
#d-i passwd/user-password-crypted password $1$3nGno0$c4rp7NcQRAcJV3AdzKV890
d-i passwd/user-password password admaster54322
d-i passwd/user-password-again password admaster54322
d-i user-setup/allow-password-weak boolean true
d-i user-setup/encrypt-home boolean false
#package
tasksel tasksel/first multiselect none
d-i pkgsel/include string openssh-server vim gcc make
d-i pkgsel/upgrade select full-upgrade
d-i pkgsel/install-language-support boolean true
d-i pkgsel/language-packs multiselect en, zh
d-i pkgsel/update-policy select none
# popularity-contest popularity-contest/participate boolean false
d-i pkgsel/updatedb boolean true
#grub
d-i grub-installer/skip boolean false
d-i lilo-installer/skip boolean true
d-i grub-installer/grub2_instead_of_grup_legacy boolean true
d-i grub-installer/only_debian boolean true
d-i grub-installer/with_other_os boolean true
# Finish
d-i finish-install/keep-consoles boolean true
d-i finish-install/reboot_in_progress note
d-i cdrom-detect/eject boolean true
d-i debian-installer/exit/halt boolean false
d-i debian-installer/exit/poweroff boolean false
