Stephen Thomas <slthomas@corpdotolin.com> wrote:
OK…I finally have to ask…
Did QNX do this just to piss off current customers? This makes smooth
migration of a QNX4 network to QNX6 nearly impossible. QSSL, what were you
thinking?
QNX4 networking is an Ethernet protocol – all addressing done at the
MAC level. (Well, it could work on other hardware, but the addressing
is still at the hardware level.) This caused began to really limit what
could be done with QNX4 networking, in particular it was not a routable
protocol. Also, if you look at QNX4 messaging, a Reply() was to a
process, assuming a unique Send() point in a process – under QNX 6
there may not be a unique MsgSend() in a process (i.e. two threads in
the same process may both be SEND blocked on the same other process,
if a Reply() is directed to that process, which thread gets the Reply()?)
QNX6 networking is based on IP, so it is routable. But, this means that,
among other things, packet format, and other rules can not be compatible.
It was a case of having to break backwards compatibility to go forward,
where backwards compatibility would have prevented this.
QNX4 & QNX6 are different operating systems – in general, if you wish
to communicate between heterogenous OSes, TCP/IP is your best choice.
So, no, we weren’t trying to piss people off. We just couldn’t do what
we wanted & needed to do for QNX6 and still make it compatible with QNX4
networking.
For QNX4 style messaging between QNX4 & QNX6 (& Linux), you might try
looking at:
http://www.bitctrl.com/produkte/qoip/kurzdok.htm
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.