We introduce
a novel high-speed
user-level communication and synchronization scheme ``Memory-Based
Communication Facilities (MBCF)''  for a general-purpose
system with an off-the-shelf communication-hardware. 
This mechanism is protected and virtualized as completely as
memory so that it can be used not only in parallel systems
but also in distributed systems.
The MBCF realizes
the direct remote-memory-accesses in user-task-spaces and offers
programmers and compilers a wide variety of functions
and a large shared-memory space.
In this paper we first explain outlines and features of the MBCF,
and present the high-speed implementation techniques for the MBCF.
Then this paper describes varieties of the MBCF functions
and introduces two novel memory-based mechanism:
the Memory-Based FIFO and the Memory-Based Signal.
Next we show that  
the MBCF is more flexible and less expensive than the
message-passing-style system-interfaces for communication
or generalized active messages.
Finally we show performance evaluations 
on the real MBCF implementation using 100BASE-TX Ethernet.