From MEPIS Documentation Wiki
The boot loader Mepis uses is called GRUB this powerful boot loader, can operate in a single boot environment or load a wide variety of free and proprietary operating systems with chain-loading. GRUB stands for GRand Unified Bootloader
The default GRUB screen in MEPIS shows 3 kernel entries followed by a MEMTEST entry, and looks something like this depending on your version of MEPIS and harddrive configuration:
timeout 15 color cyan/blue white/blue foreground ffffff background 0639a1
title MEPIS at sda1, newest kernel root (hd0,2) kernel /boot/vmlinuz root=/dev/sda1 nomce quiet splash vga=791 resume=/dev/sda4 boot
title MEPIS at sda1, previous kernel (if any) root (hd0,2) kernel /boot/vmlinuz.old root=/dev/sda1 nomce quiet splash vga=791 resume=/dev/sda4 boot
title MEPIS at sda1, kernel 2.6.22-1-mepis-smp root (hd0,2) kernel /boot/vmlinuz-2.6.22-1-mepis-smp root=/dev/sda1 nomce quiet splash vga=791 resume=/dev/sda4 boot
title MEMTEST kernel /boot/memtest86+.bin
Three kernel entries are listed for technical reasons. Warren, the developer of MEPIS, provides this explanation: "Some software, for example os-prober, only recognizes kernels that have specific entries in menu.lst, for example the 3rd entry in the usual MEPIS menu.lst. The Debian kernel installation script does something special if the vmlinuz and vmlinuz.old symlinks exist. When a new kernel is installed, it automatically becomes vmlinuz and the previous vmlinuz becomes vmlinuz.old. So if a new kernel, for example the desktop-smp kernel, is installed, then in the menu.lst it is automatically the newer kernel and the previous newer kernel becomes the older kernel. This was a simple way to allow users to add new kernels without having to edit the menu.lst every time."
The final entry, Memtest is a thorough, stand-alone memory test for 386, 486 and Pentium systems. It writes a series of test patterns to every memory address, then reads back the data written and compares it for errors.
Main Article: User:Moksha/Basic GRUB editing
The beauty of GRUB is it is highly customizable, some of the possibilities can be explored in the main article.