TrinityOS is a step-by-step, example-driven HOWTO on building a very functional Linux box with strong security in mind. TrinityOS is well known for its strong packet firewall ruleset, Chrooted and Split DNS (v9 and v8), secured Sendmail (8.x), Linux PPTP, Serial consoles and Reverse TELNET, DHCPd, SSHd, UPSes, system performance tuning, the automated TrinityOS-Security implementation scripts, and much more.
Super Grub Disk is a bootable floppy or CDROM that is oriented towards system rescue, specifically for repairing the booting process. Super Grub Disk is simply a Grub Disk with a lot of useful menus. It can activate partitions, boot partitions, boot MBRs, boot your former OS (Linux or another one) by loading menu.lst from your hard disk, automatically restore Grub on your MBR, swap hard disks in the BIOS, and boot from any available disk device. It has multi-language support, and allows you to change the keyboard layout of your shell.
Gujin is a PC boot loader that can analyze your partitions and filesystems. It finds the Linux kernel images available, as well as other bootable partitions (for *BSD, MS-DOS, Windows, etc.), files (*.kgz) and bootable disk images (*.bdi), and displays a graphical menu for selecting which system to boot. It boots the Linux kernel using the documented interface, like LILO and GRUB, so it doesn't need any other pre-installed bootloader. It can also directly load gzipped ELF32 or ELF64 files, with a simple interface to collect real-mode BIOS data. There is no need to execute anything after making a new kernel: just copy the kernel image file into the "/boot" directory, with a standard name. Gujin is written almost entirely in C with GCC, and it fully executes in real mode to be as compatible as possible.
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.