Penny's OS (S 13)

 
or MacBSD or MACE
or Mach or MachTen
or MacMach or Mach386
or Mac OS or Mac OS X
or Madrid Linux or Maemo
or Magic Cap or Magic Linux
or magnussoft ZETA or MAI Basic Four
or Mandrake Linux or Mandriva Linux
or Mangaka Linux or Manhattan OS
or MANOS or ManRiX
or MarBSD or MaRTE OS
or Maruti or MaryanLinux
or Masix or MASTER
or Maverick OS or MAX
or MaxOS or Mayix
or MazzanettoOS or MBOS/5
or MCNLive or MCP
or MCS or MCTS
or MDOS or MDX
or Mediainlinux or MeDOS
or Medusa or Medya
or MeeGo or MegaOS
or Meglos or MeikOS
or MeNTOPPIX or MenuetOS
or MEPIS or Merlin
or MERT or Metadistro-Pequelin
or M44/44X or MFT
or Michigan Terminal System or Micrium
or MicroBSD or MicroC/OS-II
or Microdisk Op Sys or MICRODOS
or Micronix or Micro OS X
or Microport UNIX or Micropower Pascal
or MICROS or MicroVMS
or Microwave OS-9 or MidnightBSD
or Midori or MikeOS
or MIKO GNYO/Linux
or Mimos or miniBSD
or MINI-EXEC or MiniKazit
or MINIMOP or Minirighi
or Minislack or MINI-UNIX
or MINIX or MiNT
or MINUX or MIPS RISC/os
or Miracle Linux or Miraculix
or MIRAGE or Miranda OS
or miray unOS or MirOS BSD
or MIT Exokernel or MiX
or MiZI Linux or MK-DOS
or MkLinux or MK++
or mkRTOS or ML
or MMOS or Mobilinux
or Möbius or Moblin
or Mockup or MOD4
or MOD-400 or MODULAR ONE
or ModulOS or MODUS4
or MoLinux or Momonga
or MonaOS or MONECS
or Monitor or Monoppix
or m0n0wall or Monta Vista Linux
or Monterey or MoonOS
or MOPSLinux or more/BSD
or Morphix or MorphOS
or Mort or MOS
or MOSIX or MOSS
or Mostly Linux or MotoMagx
or MoviX or MPE/iX
or MPE-3000 or MPE/XL
or MP/M or MP/M-86
or MP/NET or MPOS
or MP/OS or MP-RAS UNIX
or MPX or MPX-32
or MQX RTOS or MrCODE
or MSC or MS-DOS
or MS/8 or MSOS
or MSP or MSP/7
or MST UNIX or MSX
or MSX-DOS or MTDS
or MT-809 or MTK-II
or MTOS or MTS
or mtxinu or MU5
or Mulimidix or muLinux
or Mulplix or Multics
or Multi Distro or MULTIDOS
or MULTI-FORTH or MultiJob
or Multi-Programming Executive or Multiuser DOS
or MUMPS or Mungi
or MUNIX or Munjoy Linux
or MuOS or Muriqui Linux
or Murix Linux or MUSIC/SP
or Musix GNU/Linux or MUSS
or MustiOS or Mutagenix
or MUTOS 1700 or muVinix
or MVS or MVS/ESA
or MVS/SE or MVS/SP
or MVS/XA or MVT
or MV/UX or Myah OS
or MyDOS or myLinux
or MyNOS or MysticOS
or Mythbuntu or MythDora