Which RTOS?

Hi folks,

I am about to emabark on a new development using a COTS PC104 single
board computer (probably Arcom Viper) for use in an industrial control
system. The PC104 will perform the role of an autonomous serial data
acquisition hub with some basic control functions. The PC104 will be
installed in a remote location with proprietary ethernet or serial
protocols revovering data from the PC104. I expect within 2 years we
will be forced down the Modbus TCP/IP and OPC route for ethernet
communications. There will be no user interface (except for debugging)
and the only soft realtime requirements are related to the management
and efficiency of the serial interfaces.We expect a volume of 400
units/year and will be developing in accordance with SIL2 (IEC 61508).
My team currently has a skillset in similair applications on QNX 4.

We are currently considering which OS to use and are currently on a
shortlist (not exclusive) of:

Win CE 5.0
QNX 6
VxWorks
RTLinux

The evaluation is based on the following criteria (ranked in order of
priority):
1) Availability (>95% over 20 years)
2) Available skillset (Transferrable skills or Contractors in the UK)
3) License cost (per unit)
4) Training (Classroom based in the UK)
5) Portability (To other PC104 manufacturers)
6) Additional IT infrastructure for development environment.(Windows
company network)
7) BSP availability
8) Up front toolkit/license cost
9) Features
10) OS Vendor Support

We are very pleased with QNX 4 over the years but we have struggled
with 2,3,5,6,10 and it is has no BSP for our expected target.
Any advice or pointers to other resources would be appreciated.

On 2006-03-10, Nemisis_2001 <kelvinjamieson@btinternet.com> wrote:

> We are currently considering which OS to use and are currently on a
> shortlist (not exclusive) of:
>
> Win CE 5.0
> QNX 6
> VxWorks
> RTLinux

I'd probably recommend a look at eCos:

 http://ecos.sourceware.org/
 http://www.ecoscentric.com/

> The evaluation is based on the following criteria (ranked in order of
> priority):

> 1) Availability (>95% over 20 years)

Well, I've never seen it crash.

> 2) Available skillset (Transferrable skills or Contractors in the UK)

Cambridge is the eCos capital of the world.  ;)

> 3) License cost (per unit)

Free.

> 4) Training (Classroom based in the UK)

Cambridge again.

> 5) Portability (To other PC104 manufacturers)

It should run on most PC-like platforms.

> 6) Additional IT infrastructure for development environment.(Windows
> company network)

Absolutely no clue what that means.

> 7) BSP availability

Um, Yes.

> 8) Up front toolkit/license cost

Toolkit is free, unless you want to pay for one with support
from soembody like eCosCentric.

No license cost.

> 9) Features

Yes, eCos has features!

> 10) OS Vendor Support

eCosCentric is probably the big one, but there are others who
offer support as well.

-- 
Grant Edwards                   grante             Yow!  I want to kill
                                  at               everyone here with a cute
                               visi.com            colorful Hydrogen Bomb!!

"Nemisis_2001"
> Hi folks,
>
> I am about to emabark on a new development using a COTS PC104 single
> board computer (probably Arcom Viper) for use in an industrial control
> system. The PC104 will perform the role of an autonomous serial data
> acquisition hub with some basic control functions. The PC104 will be
> installed in a remote location with proprietary ethernet or serial
> protocols revovering data from the PC104. I expect within 2 years we
> will be forced down the Modbus TCP/IP and OPC route for ethernet
> communications. There will be no user interface (except for debugging)
> and the only soft realtime requirements are related to the management
> and efficiency of the serial interfaces.We expect a volume of 400
> units/year and will be developing in accordance with SIL2 (IEC 61508).
> My team currently has a skillset in similair applications on QNX 4.
>
> We are currently considering which OS to use and are currently on a
> shortlist (not exclusive) of:
>
> Win CE 5.0
> QNX 6
> VxWorks
> RTLinux
>
> The evaluation is based on the following criteria (ranked in order of
> priority):
> 1) Availability (>95% over 20 years)
> 2) Available skillset (Transferrable skills or Contractors in the UK)
> 3) License cost (per unit)
> 4) Training (Classroom based in the UK)
> 5) Portability (To other PC104 manufacturers)
> 6) Additional IT infrastructure for development environment.(Windows
> company network)
> 7) BSP availability
> 8) Up front toolkit/license cost
> 9) Features
> 10) OS Vendor Support
>
> We are very pleased with QNX 4 over the years but we have struggled
> with 2,3,5,6,10 and it is has no BSP for our expected target.
> Any advice or pointers to other resources would be appreciated.
>


Why don't you add windows xp embedded to your list? While it is a stripped 
down version of windows xp (therefore non-RTOS), there are modules available 
that implement real time in it. With that items #2, 4, 5 (given that you 
keep on winxp compatible platform), 6 and 9 come are completely met.

Up front toolkit costs around $900, and license cost is around $90 per unit, 
which could be a limiting factor in many applications. I'm using it in a 
robotic application, and while I'm not using the RTOS module, it meets all 
my expectations.

Cheers

Padu 

On Fri, 10 Mar 2006 13:36:18 -0800, Nemisis_2001 wrote:

> We are currently considering which OS to use and are currently on a
> shortlist (not exclusive) of:
> 
> Win CE 5.0
> QNX 6
> VxWorks
> RTLinux
> 
> The evaluation is based on the following criteria (ranked in order of
> priority):
> 1) Availability (>95% over 20 years)
> 2) Available skillset (Transferrable skills or Contractors in the UK)
> 3) License cost (per unit)
> 4) Training (Classroom based in the UK)
> 5) Portability (To other PC104 manufacturers)
> 6) Additional IT infrastructure for development environment.(Windows
> company network)
> 7) BSP availability
> 8) Up front toolkit/license cost
> 9) Features
> 10) OS Vendor Support
> 
> We are very pleased with QNX 4 over the years but we have struggled
> with 2,3,5,6,10 and it is has no BSP for our expected target.
> Any advice or pointers to other resources would be appreciated.

How about RTEMS (www.rtems.com)?  Viper is Intel Xscale which is ARM 5.  
RTEMS supports ARM V7 and above so that might be an issue.  RTEMS supports
many other processor families, has BSPs, and is supported on Windows and
*nix environments.  The source code is free and there are no licensing
costs.  Training and support are available (not for free)--there is a
class scheduled for Munich in mid-July.  I would hope it has high
availability--it is used on the Avenger Forward Air Defense System.


    ~Dave~

Nemisis_2001 wrote:

> Hi folks,
> 
> I am about to emabark on a new development using a COTS PC104 single
> board computer (probably Arcom Viper) for use in an industrial control
> system. The PC104 will perform the role of an autonomous serial data
> acquisition hub with some basic control functions. The PC104 will be
> installed in a remote location with proprietary ethernet or serial
> protocols revovering data from the PC104. I expect within 2 years we
> will be forced down the Modbus TCP/IP and OPC route for ethernet
> communications. There will be no user interface (except for debugging)
> and the only soft realtime requirements are related to the management
> and efficiency of the serial interfaces.

So what are the real time requirements?

Ian

Appreciate all of the responses so I will address them all at once.

I will certainly add eCos and RTEMS to the evaluation list. Redboot was
always in the running for a bootloader.

For real time Win CE appears to be a better choice than XP Embedded and
even the Microsoft website agrees.

On one side of the coin the PC104 will serve as a serial communications
master collecting analouge and digital information from serial slave
device controllers and storing in a database. The performance
requirements in this area are quite lose - all data recovered within 1
second.

On the other side the PC104 will act as a communications slave whereby
information will be (asynchronously) read by a control room serial
communciations master. In addition the this some control commands may
be issued by the control room which need to be forwarded to the serial
device controllers.

In terms of performance we are looking at a guaranteed response time of
28-32ms in response to a message from the control room and the
forwarding of control commands to device controllers within 100ms of
recieving.

In addition to this (due to bespoke modems installed betwwen control
room and PC104) we need to keep the interbyte timeouts down to less
than an average of 16/300ths of a bit over 300 bytes.

The only other real time requirements are the management of the
hardware watchdog (probably configured in the seconds range).

We have historically found that when CPU load increases the OS provided
serial interrupt handling always seems to suffer.

Best regards

On Sat, 11 Mar 2006 12:00:01 -0800, Nemisis_2001 wrote:

> Appreciate all of the responses so I will address them all at once.
> 
> I will certainly add eCos and RTEMS to the evaluation list. Redboot was
> always in the running for a bootloader.
> 
> For real time Win CE appears to be a better choice than XP Embedded and
> even the Microsoft website agrees.

Please post after your evaluation with your choice and rationale.  It
might help someone else later on.


    ~Dave~

On 11 Mar 2006 12:00:01 -0800, "Nemisis_2001"
<kelvinjamieson@btinternet.com> wrote:


>On one side of the coin the PC104 will serve as a serial communications
>master collecting analouge and digital information from serial slave
>device controllers and storing in a database. The performance
>requirements in this area are quite lose - all data recovered within 1
>second.

Are these serial devices on a single serial line or are multiple lines
used for communication ? 

If multiple lines are used, the number of free interrupts can be a
problem if ordinary UARTs are used. If some multiplexor card is used,
it is a good idea if the card is supported by the selected operation
system, otherwise you would have to write the driver yourself.

>In addition to this (due to bespoke modems installed betwwen control
>room and PC104) we need to keep the interbyte timeouts down to less
>than an average of 16/300ths of a bit over 300 bytes.

This would require a chip with a sufficiently large TX-FIFO in order
to keep the transmitter saturated at all times.

Paul

> We are currently considering which OS to use and are currently on a
> shortlist (not exclusive) of:
>
> Win CE 5.0
> QNX 6
> VxWorks
> RTLinux

I would suggest taking a look at www.on-time.com.  Their OS is very easy to 
use and well supported.  The major drawback is it is protected mode x86 
only, but if you are looking for COTS PC/104 then this may be the best 
choise processor anyway as there are lots of vendors.  The x86 target also 
has a benfit as you can use Borland and MS compilers.

> 1) Availability (>95% over 20 years)

Availability?  Up time? A 95% requirement seems very low.

> 2) Available skillset (Transferrable skills or Contractors in the UK)

The demo's that come with the download show you how to do most things you 
could want.  The x86 tools are familiar to most.


> 3) License cost (per unit)

No run time license.

> 4) Training (Classroom based in the UK)

Not available, but probably not necessary.  I would be happy to provide some 
training if you really feel this is necessary :-)

> 5) Portability (To other PC104 manufacturers)

Definately.

> 6) Additional IT infrastructure for development environment.(Windows
> company network)

Lots.

> 7) BSP availability

An industrial PC is basically a PC.

> 8) Up front toolkit/license cost

Low.

> 9) Features

See the WEB link above.

> 10) OS Vendor Support

In my experience this has been very good.

Regards,
Richard.

http://www.FreeRTOS.org

"Nemisis_2001" <kelvinjamieson@btinternet.com> wrote in message 
news:1142026578.520276.63980@u72g2000cwu.googlegroups.com...
> Hi folks,
>
> I am about to emabark on a new development using a COTS PC104 single
> board computer (probably Arcom Viper) for use in an industrial control
> system. The PC104 will perform the role of an autonomous serial data
> acquisition hub with some basic control functions. The PC104 will be
> installed in a remote location with proprietary ethernet or serial
> protocols revovering data from the PC104. I expect within 2 years we
> will be forced down the Modbus TCP/IP and OPC route for ethernet
> communications. There will be no user interface (except for debugging)
> and the only soft realtime requirements are related to the management
> and efficiency of the serial interfaces.We expect a volume of 400
> units/year and will be developing in accordance with SIL2 (IEC 61508).
> My team currently has a skillset in similair applications on QNX 4.
>
> We are currently considering which OS to use and are currently on a
> shortlist (not exclusive) of:
>
> Win CE 5.0
> QNX 6
> VxWorks
> RTLinux
>
> The evaluation is based on the following criteria (ranked in order of
> priority):
> 1) Availability (>95% over 20 years)
> 2) Available skillset (Transferrable skills or Contractors in the UK)
> 3) License cost (per unit)
> 4) Training (Classroom based in the UK)
> 5) Portability (To other PC104 manufacturers)
> 6) Additional IT infrastructure for development environment.(Windows
> company network)
> 7) BSP availability
> 8) Up front toolkit/license cost
> 9) Features
> 10) OS Vendor Support
>
> We are very pleased with QNX 4 over the years but we have struggled
> with 2,3,5,6,10 and it is has no BSP for our expected target.
> Any advice or pointers to other resources would be appreciated.
>
MicroC/OS-II.  Widely used, low cost.
The API is well defined in a commercially published book  - MicroC/OS-II, 
The Real-Time Kernel, Second Edition, Jean J. Labrosse, CMP Books, ISBN 
1-57820-103-9.
Source code comes in with the book.
Commercial license is low cost, under US$3K.
Used as course text in many universities.
Hundreds of ports to many platforms freely available from Micrium web site.
Has tcp/ip, gui, embedded filesyetem and modbus modules available.
Has been validated (by us) for use in safety-critical applications including 
DO-178B Level-A.

-- 
Scott
Validated Software Corp.