LILO is a Boot loader for Linux/x86 and other PC operating systems. It is responsible for loading your Linux kernel from either a floppy or a hard drive and passing control to it. It is capable of booting beyond cylinder 1024 of a hard disk if the BIOS supports EDD packet call extensions to the int 0x13 interface. LILO can also be used to boot many other operating systems, including DOS, Windows (all versions), OS/2, and the BSD variants. The LILO distribution includes full source, documentation and support files.
eCos (Embedded Configurable OS) is an open source, configurable, portable, and royalty-free embedded Real Time Operating System. It is written in C++, provides all the usual OS things. You configure the OS so that the parts you don't need aren't loaded to the embedded system. eCos is released under a modified GPL that allows for its use in embedded systems without having to GPL the embedded application.
GNU GRUB is a Multiboot loader. It was derived from GRUB. It is an attempt to produce a bootloader for IBM PC-compatible machines that has both the capability to be friendly to beginning or otherwise non-technically interested users and the flexibility to help experts in diverse environments. It is compatible with FreeBSD, NetBSD, OpenBSD and Linux. It supports Windows 9x/NT/2000/XP and OS/2 via chain-loaders. It has a menu interface and a command-line interface.
Yard is a suite of Perl scripts for creating rescue disks (also called bootdisks) for Linux. A rescue disk is a self-contained Linux kernel and filesystem on a floppy, usually used when you can't (or don't want to) boot off your hard disk. A rescue disk usually contains utilities for diagnosing and manipulating hard disks and filesystems.
cdrtools (formerly cdrecord) creates home-burned CDs/DVDs with a CDR/CDRW/DVD/BluRay recorder. It works as a burn engine for several applications. It supports CD/DVD/BD recorders from many different vendors; all SCSI-3/mmc- and ATAPI/mmc-compliant drives should also work. Supported features include IDE/ATAPI, parallel port, and SCSI drives; audio CDs, data CDs, and mixed CDs; full multi-session support; CD-RWs, DVD-R/-RW, DVD+R/+RW, BD-R/BD-RE; and TAO, DAO, RAW, and human-readable error messages. cdrtools includes remote SCSI support and can access local or remote CD/DVD/BD writers.