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Re: How to choose a firmware partner
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CREDIT...

Another "me too" moment. I used to do all my documentation with it. The R&D
secretary was unsure whether to thank me for saving her some work, or curse
me for making her redundant.

I loved those macro scripting facilities... much fun. I've yet to find a
modern editor that is as flexible in that respect (although one day I'll
learn how to use vim or emacs properly...).

<snip salutory tale of backups and full system disks>

Ah, well, our MDS and iPDS both had *2* drives - so nerrr! ;)

Steve
http://www.sfdesign.co.uk
http://www.fivetrees.com



Re: How to choose a firmware partner
On Wed, 26 May 2004 20:57:53 +0100, "Steve at fivetrees"

[...CREDIT story...]
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Coincidentally, the paper I was writing was sort of a farewell letter,
describing lessons learned and possible future directions the division
I was working for could take to improve products and the development
process.  I was leaving for a new job in another division of the same
company, where I would be using EMACS under VAX/VMS.

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As did ours.  The system disk was in the first drive, and the data
disk in the second.  It's been far too long for me to remember the
actual command and file syntax, but to use an MS-DOS analog, I invoked
the "save file" function, was prompted for a filename, and I entered
"a:memo.txt" or perhaps just "memo.txt" when I meant "b:memo.txt".
IIRC, ISIS used numbers rather than letters for the drive specifier,
but you get the idea...

Regards,

                               -=Dave
--
Change is inevitable, progress is not.

Re: How to choose a firmware partner

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Stop, please! I'm getting all misty eyed.

My first job out of university was with a small custom microelectronics
company developing embedded systems for the oil and gas industry. We
used the MDS but we only had one so we had to write the code on paper
and our secretary typed it in for us. She became so used to this that
she did the first level syntax check.

We were also using PL/M as a programming language, 1702 EPROMs or
battery-backed memory we used to load from the MDS and carried to the
lab.

I loved it when we could afford to get a PDP-11 with VT100 terminals.
The editor was one of the best I've ever used.

Sniff, sniff...

Oh, and we were using watchdog timers in the mid-70s. Can't imagine a
system without one or something similar, unless you're talking
sync-matched processors like the old Northern Telecom DMS-100s I used to
program for.

...Tom

Re: How to choose a firmware partner
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Can't agree here. GNU ok. PC ok. But for embedded debugging I really
appreciate a full blown emulator (of course these are dieing).

---
42Bastian
Do not email to snipped-for-privacy@yahoo.com, it's a spam-only account :-)
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Re: How to choose a firmware partner
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umm... i'm pretty sure various engines in the 1800s had teh equivalent of
watchdog timers and so did (and do) many mainframes.

--
    Sander

+++ Out of cheese error +++

Re: How to choose a firmware partner
On Fri, 16 Jul 2004 20:40:00 +0000 (UTC), Sander Vesik

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Can you name any of these mainframes ?

I do not see a reason why anybody would use them.

In computer systems with memory protection hardware, illegal
addresses, garbled data or garbled code usually caused segment fault,
parity error traps and illegal opcode traps, i.e. hardware interrupts
that are vectored into kernel mode space. The interrupt handler may
then decide what to do, try to recover or print CRASH and dump the
registers on the console and then halt or reboot the system.

On mainframes with a separate console processor, the console processor
may try to check the sanity of the main processor, but even then, the
decision to reboot is usually done manual.

Paul


Re: How to choose a firmware partner
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Well, back in those days, the watchdog timers would usually come in
the shape of trained personnel.  They'ld be taught to check certain
status indicators on a regular basis, and raise a fuss if anything
appeared to be out of hand..

The classical example of a pre-computer age watchdog would be the
"dead-man switch" on locomotives.  Unless disarmed regularly by the
chauffeur, it would bring the train to a stop.


--
Hans-Bernhard Broeker ( snipped-for-privacy@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

Re: How to choose a firmware partner
On 26 May, in article
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In various guises there have existed forms of watchdog 'timers' even in
machinery before computers, the concept was transferred from various other
spheres (even the night watchman doing his rounds) to computing.

I remember dealing with small quantity testing of Watchdogs for PDP-11's
circa 1979 which had loud sounders attached to them, also the one that was
designed for the QBus writing the diagnostic setup programme a few years later.
These used standalone timers and even one shots so there was minimal logic to
be affected by system activity and go wrong!

Even the one I dealt with circa 1979 was a design at least 2 years old as it
was a repeat order.

--
Paul Carpenter        | snipped-for-privacy@pcserv.demon.co.uk
<http://www.pcserv.demon.co.uk/ Main Site
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Re: How to choose a firmware partner

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Fine. That is why I have to power-cycle my settop box from time to
time. If they only had build in a WDT, I would not have to climb
behind my TV (of course the settop box has no switch, also a new
_invention_).


---
42Bastian
Do not email to snipped-for-privacy@yahoo.com, it's a spam-only account :-)
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Re: How to choose a firmware partner
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systems run

Absolutely - I (or rather my daughter) is adept at this. Set-top boxes seem
to be particularly bad, and I believe I know why...

Steve
http://www.sfdesign.co.uk
http://www.fivetrees.com



Re: How to choose a firmware partner

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Do tell.  (I can crash my set top box in about 10 seconds without even
trying.  Luckily it has a power switch on the front).

Robert

--

Re: How to choose a firmware partner
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seem

Brief version: this area seems to suffer from the Curse of The Inappropriate
RTOS. Or perhaps it's appropriate, due to all the various 3rd-party comms
layers required... but in any case, said RTOS doesn't seem to cope with
processing key events terribly fast. Which seems kinda lame.

The longer version involves the amount of times I've talked myself out of a
job with set-top box manufacturers.

Steve
http://www.sfdesign.co.uk
http://www.fivetrees.com



Re: How to choose a firmware partner
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Are you referring to a Sky digibox by any chance?
I have to reboot mine at least twice a week.

Andy


Re: How to choose a firmware partner
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seem

I've had a Sky box, and yes, it was fragile. I was actually referring to my
Nokia freeview receiver - which my daughter (she of the phn txt skl) manages
to crash in seconds.

Steve
http://www.sfdesign.co.uk
http://www.fivetrees.com



Re: How to choose a firmware partner
On Wed, 26 May 2004 12:30:02 +0100, "Steve at fivetrees"

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I have never even considered of using a watchdog timer, but might
reconsider, if I had to design something for high radiation (space)
environment with SEUs etc.

In any safety critical systems, I would not even consider to use any
processor based (or even sequential logic based) systems, but instead
rely on mechanical, pneumatic or hydraulic systems.

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I have not been working with hardware recently, but by impression was
that the CE requirements required that the device should withstand a
few kV charged into a few nF capacitor and then discharged at the
metalwork _and_ the input and output pins.

In addition to pin protection, this also requires that you pay
attention to ground plane design.

Paul


Re: How to choose a firmware partner
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<Sigh>

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<Sigh>

Sorry, I'm tired. I'll let someone else point out why you're not entirely
wrong, and why watchdogs are indispensable anyway.

Steve
(who has been working with hardware recently)
http://www.sfdesign.co.uk
http://www.fivetrees.com



Re: How to choose a firmware partner
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How do you know if you have the optimum distribution of

clear-WDT

instructions?

If your system is simple enough to predict this, then it is simple
enough to code without the risk of depending on state to avoid lockup.

If your system is too complicated to predict optimum distribution then
you must err on the safe side allowing bugs to remain undetected
because they are masked by watchdog resets.


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Yes we do this, without problems. Our code is inherently safe. This is
easy to do because it is small.

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I was afraid someone would say that.

Robin

Re: How to choose a firmware partner
On 27 May 2004 02:30:14 -0700, snipped-for-privacy@tesco.net

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That explains your statement, I guess, but you misunderstand the
purpose of the watchdog. It's not to protect against coding errors.
Hardware breaks.

--
Al Balmer
Balmer Consulting
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Re: How to choose a firmware partner
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Indeed.

To Robin: more saliently, it also gets zapped - non-destructively, but
enough to cause it to go "off in the weeds". See post re electrically noisy
environments. CE marking etc be damned - not too much one can do about this
kind of noise (including care in ground plane design - yawn - which is a
given, I'd thought) except detect the effects and recover.

As another poster said, designing embedded systems (esp. unattended systems)
without a watchdog is tantamount to driving without insurance. This isn't a
matter of opinion, it's a matter of hard-won experience.

Steve
http://www.sfdesign.co.uk
http://www.fivetrees.com



Re: How to choose a firmware partner
My old business partner was in full agreement with you.

He was capable of witting code that could run for days without locking up
(which proved it was bug free).

-Hershel


On 26-May-2004, snipped-for-privacy@tesco.net ( snipped-for-privacy@tesco.net) wrote:

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