VxWorks->HP-RT port

VxWorks->HP-RT port

Post by Ray Tacke » Wed, 07 Jul 1993 00:56:08



Does anyone have experience porting large applications from VxWorks to HP-RT
or LynxOS?  I would be interested in learning about problem areas you
encountered and any advice you would like to impart.

--
Ray Tackett  

 
 
 

VxWorks->HP-RT port

Post by Roebe » Wed, 07 Jul 1993 22:51:38


Ray , You asked:

Quote:>  Does anyone have experience porting large applications from VxWorks to HP-RT
>  or LynxOS?  I would be interested in learning about problem areas you
>  encountered and any advice you would like to impart.

We have been heavy users of VxWorks on our embedded projects.  We have used
Silicon Graphics (SGI) workstations on a number of other projects that had less
demanding real time requirements.  SGI has a great version of UNIX that has
real good real time features.  We have been contemplating using LYNX-OS on
some applications to get some of the ease of development that UNIX provides
while still getting fairly reasonable real time performance.  While I have
done a lot of reading on LynxOS, we don't have any hard experience yet.  I
am our local OS expert though so would be interested in any good responses
you get back.
  My take on going to LynxOS is that it isn't simple if you are real familiar
with VxWorks.  If you are real familiar with UNIX, it should be easier.
Lynx provides a pretty good POSIX compliant kernel.  It has much better
performance than most UNIX versions as well as most of the necessary real
time enhancements that the good UNIX versions provide (e.g. SUN SOLARIS or
SGI Irix but NOT HP-UX).  Like any UNIX, however, there are things about
Lynx that are very different from VxWorks.  SOme of them are:
- uses the MMU to provide a virtual memory environment.  This provides
  memory protection which helps development but also prevents easy data
  sharing.  It also introduces a lot of timing uncertainty.
- Can support demand paged applications like a normal UNIX.  This allows
  applications that are bigger than physical memory but really plays havoc
  on timing.  You can't run with this disabled though.
- Provides real POSIX interfaces to many functions.  These are different
  from a lot of the VxWorks ones (VxWOrks is a UNIX look-alike whereas Lynx
  is UNIX).
- Provides pretty powerful multiprocessor support.  VxWorks is just starting
  to provide limited multiprocessing.  Lynx seems to offer much more as well
  as different models (e.g. tightly coupled with full process migration,
  snuggly coupled with no process migration but data sharing, and loosely
  coupled like VxWOrks).
I could go on but those are the main points.  Again, I would be interested
in any other responses you get.   Fred

   |  Fred J Roeber,  Raytheon Submarine Signal Division   |
   |  1847 West Main Road,  Mail Stop 177                  |
   |  Portsmouth, RI  02871-1087  (401) 842-4205           |