Some funny MS Propaganda

Michael mjc106-/E1597aS9LQAvxtiuMwx3w at public.gmane.org
Thu Oct 2 04:41:28 UTC 2003


> Depends on how you define unix :)  These days the Internet
> basically runs
> on Cisco boxes.  Cisco's OS is called IOS and is infact a cut down
> version
> of unix (BSD flavour I think).  I don't really think of it as a
> unix
> anymore though as it is quite divergent.  Once apon a time before
> there
> were dedicated routers almost all routing was done through unix
> boxes.

Okay, first of all "running The Internet" is a vague term, generally
my own experience suggests that the servers not the routers run the
Internet - I know it sounds odd but that seems to be the convention.
(I may be wrong on that point.)

Now as for IOS... okay yes Cisco boxes run IOS, which is a big bad
ugly name (bad and ugly because it does not really describe what IOS
is) for what is nothing more than a shell that runs on top of QNX.
Basically IOS is what the router administrator uses to modify the
router configuration, for example set up VLANs (it runs on Cisco
switches too) set up routes, change Routing Protocols (not to be
confused with routed protocols), and so on.

The point is IOS is a lot of I (as in Interface) and not really an
OS. So what runs a Cisco router? QNX. QNX is designed to feel like
Unix, but it is NOT Unix. Not by a million miles is QNX even close to
Unix.

You can read tons on QNX at a number of places:

http://www.qnx.com
http://student.math.uwaterloo.ca/~cs452
http://mjc88.0catch.com

Now a little history lesson. In the late 1970s two U of Waterloo
computer science students (a grad student who had a B Sc in Physics -
from UW) and a 4'th year undergrad took a course, CS 452 (Real Time
Programming) anyone here, who took CS at U(W) can tell you about the
infamous "trains course". - You need to build a real time OS that
runs on bare hardware (currently on an i486, back in the 70's it was
something else obviously) then you need to build an application that
talks to a toy train set and makes the trains to amazing things. You
have three months and you can work in teams of one or two, good luck!
- Anyway back in the 70s our heroes took the above course and were so
inspired, delighted, shocked into total insanity, that they decided
to open up a little company in their home town (Ottawa) to sell there
little project which they called QNX.

(I also took CS 452 and that's why a. I know all about this and b.
why I still cower at the sight of toy train sets.)

Now the reason you read my little tale, QNX is based on a CS 452 OS
project, CS 452 was the brain child of a PhD student who had this
nifty idea: "why not strip everything you don't totally need out of
the OS kernel and use IPC to do everything the kernel traditionally
does." In other-words, why not make a Micro kernel, and use special
mechanism for IPC, the special mechanisms are called kernel
primitives, and there are three:

int send(void * pid, void * msg, int length);
int receive(void * msg, void * senderPID);
reply(void * msg, int length);

(Its been a while, I may have the syntax wrong, sorry.)

Now you build these synchronous kernel primitives and then you build
yourself serial servers, keyboard servers, video servers and you have
yourself an OS which you can sell to Cisco systems and make your
millions.

Now why would Cisco want a micro kernel instead of a monolithic? Well
for one thing Micro Kernels service interrupts really really fast,
for another thing, it is much easier to assert that QNX will really
be hard real time than say RT Linux.

Where can I take a course as interesting and exciting as CS 452? (If
you really want to know the answer to that question you probably
ought to turn yourself in to the Queen Street mental health unit,
otherwise if you really want to know the answer go take CS 452 at
U(W).)


Anyway if you have further questions, try one of the above web sites.

Michael

Oh almost forgot, on an unrelated aside, Cisco started as a husband
and wife team in their living room, financed by credit cards, they
sold routers and moon lighted as consultants. :-)

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