Device and file-system drivers, as well as other system services, are implemented by a collection of user-space tasks (servers), creating thus the multiserver nature of HelenOS.

It can be used to send small fixed-size messages, blocks of bytes or to negotiate sharing of memory.

Messages can be forwarded without copying bulk data or mapping memory to the address space of middle-men tasks.

The developer community consists of a small core team, mainly staff and former and contemporary students of the Faculty of Mathematics and Physics at Charles University in Prague, and a number of contributors around the world.

HelenOS is being used for research[17][18] in the area of software components and verification by the Department of Distributed and Dependable Systems, Charles University, Prague.