Syslinux

The SYSLINUX project encompasses a set of lightweight bootloaders, for booting computers into the Linux operating system. It is the work of H. Peter Anvin and is made up of several different systems.

List

• The SYSLINUX original, used to boot from FAT file systems (usually flexible disks or USB sticks).
• ISOLINUX, used to boot from ISO 9660 CD-ROM file systems.
• PXELINUX, used to boot from a network server with the system Pre-rank execution environment (PXE).
• EXTLINUX, used to boot from Linux ext2 file systems, ext3, ext4 or btrfs.
• MEMDISK, used to boot older operating systems like MS-DOS from memory.
• Two separate menu systems.
• A development environment for additional modules.

Use

SYSLINUX and ISOLINUX

SYSLINUX is not normally used to boot full Linux installations since Linux rarely installs on FAT file systems. Instead, it is often used for bootable or rescue floppies, LiveUSBs, or other lightweight bootable systems. ISOLINUX is generally used for installable Linux LiveCDs or bootable CDs.

A minor complication appears when booting from CD-ROM. El Torito (Standard CD-ROM) allows you to boot in two different modes;

• floppy emulation modewhere boot information is stored in a flexible disk image file, which is loaded from the CD, and then behave like a flexible virtual disk. This image file is effectively a FAT file system, so SYSLINUX is the necessary boot loader.
• mode without emulationwhere boot information is stored directly on the CD. In this mode you need ISOLINUX.

However, having a choice is sometimes useful as ISOLINUX is vulnerable to BIOS errors, in which case it is handy to be able to boot using SYSLINUX. This mostly affects computers built before 1999 or so, and in fact, for modern computers, no-emulation mode is generally the most reliable method.

PXELINUX

PXELINUX is used in conjunction with a suitable image for PXE on a network card. The PXE environment uses DHCP or BOOTP to enable a basic TCP/IP connection, and then downloads a boot program over TFTP. This boot program loads and configures the kernel according to directives that are also obtained from the TFTP server.

PXELINUX is typically used for Linux installations from a central network server or for diskless booting of workstations.

EXTLINUX

EXTLINUX is normally used as a general purpose boot loader, similar to LILO or GRUB.