On 5 April 2014 07:56, Sean Conner
<sean@conman.org> wrote:
[1] And oddly enough, performance. Back in the mid-90s, some friends of
mine worked at a company that produced commercial X servers. Their
fastest version ran on QNX [2], a purely message passing based
operating system. Even the X servers that used shared memory were
slower than their QNX version.
It's even funnier than that. I worked at Quantum-later-QNX. There was a phase (pre-QNX4) where the '386 version of QNX did the message passing via shared memory. This was stripped out from QNX4 (and probably later) because it turned out that it was SLOWER to share memory than to copy it between processes.
People who think message passing is slow have never used a realtime system. Most RMXes are based on message passing for a reason.