<Tr> <Td> CRUX </Td> <Td> CRUX is a lightweight, x86 - 64 - optimized Linux distribution targeted at experienced users . The focus is "keep it simple", which is reflected in a simple tar. xz - based package system, BSD - style initscripts, and a relatively small collection of trimmed packages </Td> </Tr> <Tr> <Td> DD - WRT </Td> <Td> Embedded firewall Linux distribution </Td> </Tr> <Tr> <Td> Dragora GNU / Linux - Libre </Td> <Td> A Linux distribution written entirely from scratch and sharing some similarities with Slackware . Approved by the GNU Project as a free operating system . </Td> </Tr> <Tr> <Td> ELinOS </Td> <Td> Linux distribution for embedded systems by SYSGO . ELinOS focuses on industrial application and provides real - time extensions . </Td> </Tr>

What are the types of linux operating systems