Software engineer ( Embedded systems, RTEMS, Linux)

Mostly C, sometimes C++ and assembler.
PowerPC and i386 architectures, software for routers, switches
(proprietary OS and Linux)

BSD TCP/IP stack (porting, developing), networking services (NAT, IPSEC protocol for RTEMS, packet filtering, OSPF/BGP, ssh server, multilink ppp ... ), hardware drivers.