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.

MenuetOS is a name you might have NOT heard before, if not let me introduce to this little beauty. The open-source, GUI capable operating-system for x86 architecture is written entirely in assembly language which makes it highly efficient and allows it to fit on a floppy-disk. The operating-system just went to version 1.0 after 13 years of development, despite being tiny in size it supports full range of services needed to be a complete OS like support for USB devices like storage, printers, webcams and digital TV tuners and support for gaming, multimedia and basic networking. The MenuetOS supports multitasking with multiprocessor and multithreading, skinnable GUI upto 1920x1080 (16 million colors), capability to run games like Doom, Quake and utilities like DosBox and many more unimaginable features for an OS sizing less then 1.4 MB in size.