isolinuxbin

Isolinuxbin refers to the binary component used by the ISOLINUX bootloader, a part of the Syslinux project. It enables Linux to boot from ISO 9660 optical media such as CDs and DVDs and is commonly found on bootable ISO images created for installation or live systems. The standard filename for this loader is isolinux.bin.

On an ISO image, isolinux.bin is typically placed in the isolinux/ directory. When a system boots from optical media, the BIOS uses the El Torito boot catalog to load isolinux.bin, which then takes control of the boot process and reads its configuration from isolinux.cfg. The configuration governs how the loader locates the kernel and initrd, as well as boot options and menu behavior.

Isolinux.bin loads the Linux kernel and initial ramdisk described in isolinux.cfg, using kernel command line options specified by APPEND entries. It provides a boot menu, timeout, and mechanisms to customize boot behavior. The configuration typically defines paths to vmlinuz and initrd, along with labeled boot entries and any required boot parameters.

Isolinux.bin targets legacy BIOS environments; UEFI-based booting relies on different mechanisms, such as GRUB2 with an EFI stub or a dedicated UEFI-compatible Syslinux module. The boot process is constrained by the ISO 9660 filesystem layout and El Torito specifications, which govern how the image is presented to the BIOS.

Developed as part of the Syslinux project, isolinux.bin is distributed under the GPL and is used in conjunction with other Syslinux tools. Creating a bootable ISO involves including isolinux.bin in the ISO’s isolinux/ directory, along with isolinux.cfg and the kernel/initrd files, to enable a working boot experience from optical media.