The amazing MenuetOS sizing ~ 1.4 MB has a sibling. Known as KolibriOS, the open-source operating system is a forked off project being devloped separately from MenuetOS since 2004. The tiny but incredibly powerful and fast operating system comes bundled in roughly 6 megabytes megabyte of disk space and needs only 8MB of RAM to run. In comparison to it's parent 'MenuetOS', Kolibri features a rich set of extra applications that include word processor, image viewer, graphical editor, web browser, well over 30 exciting games and has 200+ applications developed so far. Full read/write for FAT12/16/32 and read-only access for NTFS, ISO9660 and Ext2/3/4 is supported. Kernel and drivers (supports all popular sound, network and graphics cards) are written entirely in FASM assembly language giving the OS it's signature speed, the developer dares users to compare it's speed with OS heavyweights Windows and Linux. Don't forget to watch the video demo posted below.

KolibriOS Features :

• A monolithic preemptive kernel that is less then 100 kilobytes in size, complete with streams, parallel execution of system calls and a TCP/IP stack.
• Speed: Thanks to being (carefully) written in Assembler, it's very fast.
• Size: KolibriOS is very small - The kernel and most of the programs fit on a 1.44MB floppy disk!
• Filesystem support: Read/write support for FAT16/32 (with long file names) and ext2/3/4, read-only support for NTFS, CDFS and XFS.
• Lightweight: Kolibri boots on any computer that has a Pentium (i586) compatible processor and at least eight megabytes of RAM.
• Hardware support: A lot of the popular sound, network and graphics cards are supported (see supported hardware list)
• Comes with a development kit (code editor with FASM macro-assembler integrated).