Penny's OS (S 4)

 
or DAC or DACNOS
or DAD or Damn Small BSD
or Damn Small Linux or Damn Vulnerable Linux
or DangerOS or DANIX
or The Dark Star or DARKSTAR Linux
or DART or Data ONTAP
or Dave's Robotic Operating System or DAVIX
or DBLDOS or DBOS
or DCC or DC/OSx
or DD OS or DD-WRT
or DeadCD or Debian
or Debian-BR-CDD or Debian JP
or Debris Linux or DebXPde
or DEC OSF/1 or Deep-Water
or DEFT Linux or Degenerate OS
or DeLi Linux or Delitalk
or Delix Linux or Dell Unix
or Deming OS or Demolinux
or DEMOS or DEMOS/MP
or DeMuDi or Denix Server
or DEOS or Desktop BSD
or DesktopTwo or DESKWORK
or DESQview+ or DESQview/X
or DES RT or De2
or DevelLinux or Devil-Linux
or Dex4U or dex-os
or DF-DOS or DG/UX
or Digital Unix or dingOS
or DISTOS or DISTRIX
or Dizinha Linux or DJS200/XT1
or DK/DOS or DLD
or DMERT or DMS
or DNALinux or DNIX
or DomainIX or Domain/OS
or DoOrS or DOS
or DOS-11 or DOS-15
or Dosket or DOS-99
or DOS Plus or DOS/360
or DOS/VS or DOS/VSE
or DOS XE or DOS XL
or DPCX or DPPX
or Draco or DragonFly BSD
or DragonLinux or Dragora
or DRBL or DR-DOS
or Dreamlinux or DreamOS
or the dr'ex kernel or DRM System
or DROPS or DROS
or DrRtos or Drywell OS
or DSLinux or DSM-11
or DSOS or DSPLinux
or DSPnano RTOS or DSU
or DTIX or DTOS
or DTSS or Dualix
or DUnix or DVIX
or DX-DOS or DX-10
or Dynacube or Dynatos
or dyne:bolic or Dynix
or Dynix/ptx or Dzongkha Linux