Syslinux
Syslinux是一個優秀的系統啟動加載器，可引導自硬盤、光盤和通過PXE的網絡啟動。支持fat, ext2, ext3, ext4 and btrfs文件系統.
注意: 從Syslinux 4起, Extlinux和Syslinux是指同一個東西的 Contents
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Syslinux 引導過程
電腦啟動時，會先加載MBR (/usr/lib/syslinux/mbr.bin)，然后MBR查找那些活動的分區（標注了可啟動的），找到這個分區后，卷啟動記錄程序（VBR=volume boot record）將被執行。如果是ext2/3/4和fat 12/16/32，ldlinux.sys開始的扇區是被寫死進卷啟動記錄程序里的，卷啟動記錄程序將執行(ldlinux.sys)。當然，如果ldlinux.sys 的位置發生改變，syslinux將無法加載。如果是btrfs，因為文件不斷移動導致ldlinux.sys扇區的位置不斷變化，而讓上面方法失效。從而使得整個syslinux需要被存儲在文件系統之外。程序將被存儲在卷啟動記錄程序之后。
當syslinux完全加載完畢，它將自動尋找一個配置文件，名字叫 extlinux.conf 或者syslinux.cfg.找到之后，將加載整個配置文件，否則，將給出提示。
安裝
自動完成安裝
syslinux-install_update腳本將自動安裝Syslinux, 復制COM32模塊到/boot/syslinux, 設置啟動標識，安裝到MBR.可自動根據softraid處理MBR和 GPT磁盤。
下面是過程： 1. 安裝Syslinux
pacman -S syslinux2. 確認/boot是否已經加載
3. 運行腳本syslinux-install_update ，參數使用 -i (安裝) -a (設可啟動標識) -m (安裝到mbr)
4. 修改配置文件 /boot/syslinux/syslinux.cfg
Note: For this to work with GPT, the gptfdisk package is needed as the backend for setting the boot flag.手工完成安裝
Note: 若你不知你所使用的分區表是使用什么 (MBR or GPT), 默認一般使用的是MBR分區表。大部分情況下，GPT將使用整個磁盤創建一個特殊的MBR-類型的分區(type 0xEE) ，使用下面命令可顯示： # fdisk -l /dev/sda或者可以這樣：
# sgdisk -l /dev/sda若其非GPT磁盤，將顯示 " GPT: not present".
Note: If you are trying to rescue an installed system with a live CD, be sure to chroot into it before executing these commands. If you do not chroot first, you must prepend all file paths (not /dev/ paths) with the mount point.Make sure you have the syslinux package installed. Then install Syslinux onto your boot partition, which must contain a fat, ext2, ext3, ext4, or btrfs file system.
# mkdir /boot/syslinux # extlinux --install /boot/syslinux #run on a mounted directory (not /dev/sdXY) /boot/syslinux/ is device /dev/sda1MBR分區表
需要標識啟動分區為激活狀態.可用這些工具實現：fdisk, cfdisk, sfdisk, (g)parted.最后結果看起來是這樣：
# fdisk -l /dev/sda [...]Device Boot Start End Blocks Id System /dev/sda1 * 2048 104447 51200 83 Linux /dev/sda2 104448 625142447 312519000 83 Linux安裝到主啟動卷區:
# dd bs=440 conv=notrunc count=1 if=/usr/lib/syslinux/mbr.bin of=/dev/sdaGUID Partition Table aka GPT
Main article GUID_Partition_Table
Bit 2 of the attributes for the /boot partition need to be set.
# sgdisk /dev/sda --attributes=1:set:2This would toggle the attribute legacy BIOS bootable on partition 1
Verify:
# sgdisk /dev/sda --attributes=1:show 1:2:1 (legacy BIOS bootable)安裝主啟動卷區:
# dd bs=440 conv=notrunc count=1 if=/usr/lib/syslinux/gptmbr.bin of=/dev/sda重啟
如果此時重啟，會有提示，以確認是自動啟動還是給出一個啟動菜單，此時需要創建一個配置文件。
配置 syslinux
syslinux的配置文件 syslinux.cfg 必須和syslinux放在同一個目錄下，在我們的例子中，是 '/boot/syslinux/'
啟動器將自動尋找這兩個配置文件：syslinux.cfg (優先) 或者 extlinux.conf
補充:
- Instead of LINUX, the keyword KERNEL can also be used. KERNEL tries to detect the type of the file, while LINUX always expects a Linux kernel.
- TIMEOUT 的值是1/10秒，也就是50代表5秒
示例
比較簡單的 Syslinux 配置
這是一個非常簡單的配置，有啟動提示，并且在5秒后自動啟動第一個系統。
配置文件:
PROMPT 1 TIMEOUT 50 DEFAULT archLABEL archLINUX ../vmlinuz-linuxAPPEND root=/dev/sda2 roINITRD ../initramfs-linux.imgLABEL archfallbackLINUX ../vmlinuz-linuxAPPEND root=/dev/sda2 roINITRD ../initramfs-linux-fallback.img若不想看到提示，設置PROMPT（顯示時間）為0.
文本的啟動菜單
把模塊menu COM32復制到syslinux目錄中，即可使用文本菜單：
# cp /usr/lib/syslinux/menu.c32 /boot/syslinux/若沒有給/boot單獨分區，且和/usr同一分區，那么，也可以僅使用一個軟鏈接:
# ln -s /usr/lib/syslinux/menu.c32 /boot/syslinux/配置:
UI menu.c32 PROMPT 0MENU TITLE Boot Menu TIMEOUT 50 DEFAULT archLABEL archMENU LABEL Arch LinuxLINUX ../vmlinuz-linuxAPPEND root=/dev/sda2 roINITRD ../initramfs-linux.imgLABEL archfallbackMENU LABEL Arch Linux FallbackLINUX /vmlinuz-linuxAPPEND root=/dev/sda2 roINITRD /initramfs-linux-fallback.img更多信息可見： http://git.kernel.org/?p=boot/syslinux/syslinux.git;a=blob;f=doc/menu.txt.
圖形化的啟動菜單
把vesamenu COM32移入到syslinux目錄中，可使用圖形啟動界面:
# cp /usr/lib/syslinux/vesamenu.c32 /boot/syslinux/若沒有給/boot單獨分區，且和/usr同一分區，那么，也可以僅使用一個軟鏈接:?:
# ln -s /usr/lib/syslinux/vesamenu.c32 /boot/syslinux/This config uses the same menu design as the Arch Install CD: syslinux.cfg
The background file can be found here: splash.png
Config:
UI vesamenu.c32 DEFAULT arch PROMPT 0 MENU TITLE Boot Menu MENU BACKGROUND splash.png TIMEOUT 50MENU WIDTH 78 MENU MARGIN 4 MENU ROWS 5 MENU VSHIFT 10 MENU TIMEOUTROW 13 MENU TABMSGROW 11 MENU CMDLINEROW 11 MENU HELPMSGROW 16 MENU HELPMSGENDROW 29# Refer to http://syslinux.zytor.com/wiki/index.php/Doc/menuMENU COLOR border 30;44 #40ffffff #a0000000 std MENU COLOR title 1;36;44 #9033ccff #a0000000 std MENU COLOR sel 7;37;40 #e0ffffff #20ffffff all MENU COLOR unsel 37;44 #50ffffff #a0000000 std MENU COLOR help 37;40 #c0ffffff #a0000000 std MENU COLOR timeout_msg 37;40 #80ffffff #00000000 std MENU COLOR timeout 1;37;40 #c0ffffff #00000000 std MENU COLOR msg07 37;40 #90ffffff #a0000000 std MENU COLOR tabmsg 31;40 #30ffffff #00000000 stdLABEL archMENU LABEL Arch LinuxLINUX ../vmlinuz-linuxAPPEND root=/dev/sda2 roINITRD ../initramfs-linux.imgLABEL archfallbackMENU LABEL Arch Linux FallbackLINUX ../vmlinuz-linuxAPPEND root=/dev/sda2 roINITRD ../initramfs-linux-fallback.img
Since Syslinux 3.84 vesamenu.c32 supports the "MENU RESOLUTION $WIDTH $HEIGHT" directive.To use it, insert "MENU RESOLUTION 1440 900" into your config for a 1440x900 resolution.The background picture has to have exactly the right resolution however as syslinux will otherwise refuse to load the menu.
Chainloading
If you want to chainload other operating systems (such as Windows) or boot loaders, copy (or symlink) the chain.c32 module to the syslinux folder (for details, see the instructions in the previous section). Then, create a section in the configuration file:
LABEL windowsMENU LABEL WindowsCOM32 chain.c32APPEND hd0 3hd0 3 is the third partition on the first BIOS drive - drives are counted from zero, but partitions are counted from one. For more details about chainloading, see [1].
If you have grub2 installed in your boot partition, you can chainload it by using:
LABEL grub2MENU LABEL Grub2COM32 chain.c32append file=../grub/boot.imgThis maybe required for booting from iso images.
使用內存測試 memtest
使用下面的 LABEL章節部分，可加載(需要安裝軟件包：memtest86+，否則不起作用):
LABEL memtestMENU LABEL Memtest86+LINUX ../memtest86+/memtest.bin使用硬件探測工具HDT
HDT (Hardware Detection Tool) displays hardware information. Like before, the .c32 file has to be copied or symlinked from /boot/syslinux/.For pci info either copy or symlink /usr/share/hwdata/pci.ids to /boot/syslinux/pci.ids
LABEL hdtMENU LABEL Hardware InfoCOM32 hdt.c32重啟和關閉電源
Use the following sections to reboot or power off your machine.
LABEL rebootMENU LABEL RebootCOM32 reboot.c32LABEL poweroffMENU LABEL Power OffCOMBOOT poweroff.com常見問題
I have a Syslinux Prompt - Yikes!
You can type in the LABEL name of the entry that you want to boot (as per your syslinux.cfg). If you used the example configs just type
boot: archIf you get an error that the config file could not be loaded you can pass your needed boot parameters, e.g.:
boot: ../vmlinuz-linux root=/dev/sda2 ro initrd=../initramfs-linux.imgIf you don't have access to 'boot:' in ramfs, and therefore temporarily unable to boot kernel again
1) create temp directory, in order to mount your root partition (if it doesn't exist already)
mkdir -p /new_root2) mount / under /new_root (in case /boot/ is on same partition, otherwise you'll need to mount them both)
mount /dev/sd[a-z][1-9] /new_root3) use 'vi' and edit syslinux.cfg again to suit your needs and save file;
4) reboot
某些電腦中，會出現沒找到默認配置或者界面
Certain motherboard manufacturers have less compatibility for booting from USB devices than others. While an ext4 formatted usb drive may boot on a more recent computer, some computers may hang if the boot partition containing the kernel and initrd are not on a fat16 partition. to prevent an older machine from loading ldlinux and failing to read syslinux.cfg, use cfdisk to create a fat-16 partition (<=2GB) and format with
# pacman -S dosfstools # mkfs.msdos -F 16 /dev/sda1then install and configure syslinux.
MISSING OPERATING SYSTEM
If you get this message, check if the partition that contains /boot has the boot flag enabled. If the flag is enabled, then perhaps this partition starts at sector 1 rather than sector 63 or 2048. Check this with fdisk -l. If it starts at sector 1, you can move the partition(s) with gparted from a rescue disk. Or, if you have a separate boot partition, you can back up /boot with
cp -a /boot /boot.bakand then boot up with the arch install disk. Next, use cfdisk to delete the /boot partition, and recreate it. This time it should begin at the proper sector, 63. Now mount your partitions and chroot into your mounted system, as described in the beginners guide. Restore /boot with the command
cp -a /boot.bak/* /bootCheck if /etc/fstab is correct. Then run
/usr/sbin/syslinux-install_update -iamand reboot.
Windows boots up! No Syslinux!
Solution: Make sure the partition that contains /boot has the boot flag enabled. Also, make sure the boot flag is not enabled on the windows partition. See the installation section above.
The MBR that comes with syslinux looks for the first active partition that has the boot flag set. The windows partition was likely found first and had the boot flag set. If you wanted you could use the MBR that windows or msdos fdisk provides.
進入子菜單，但干不了任何事
You select a menu entry and it does nothing. It "refreshes" the menu
This usually means that you have an error in your configuration. Hit TAB to edit your boot parameters. Alternatively, press ESC and type in the LABEL of your boot entry (Example: arch)
無法刪除ldlinux.sys
ldlinux.sys has the immutable attribute set which prevents the file from being deleted or overwritten. This is because the sector location of the file must not change or else syslinux has to be reinstalled.To remove:
chattr -i /boot/syslinux/ldlinux.sys rm /boot/syslinux/ldlinux.sys更多信息可見
- The Syslinux Project's website.
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