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How to choose a firmware partner

Started by robi...@tesco.net May 26, 2004
"CBarn24050" <cbarn24050@aol.com> wrote in message
news:20040526113523.17668.00001101@mb-m15.aol.com...
> > > >Watchdogs are not there to protect against dodgy code and/or unduly > >"vulnerable" hardware. They're there because, ultimately, *all* hardware
is
> >vulnerable. It's just a question of degree. If you don't believe me,
equip
> >yourself with a Schaffner and try dumping a fast-rise time 2kV spike into > >nearby metalwork... > > The watchdog timer is a fairly recent invention, millions of older systems
run
> fine without them.
It's exactly as old as embedded microprocessors. (I know. I was there.) It's dumb having one without the other. Steve http://www.sfdesign.co.uk http://www.fivetrees.com
CBarn24050 wrote:

>The watchdog timer is a fairly recent invention,
The first watchdog timers I came across was in 1980 and had been included in the product for a year or two prior to that. As this was roughly the dawn of embedded processing it is not what I would call "fairly recent."
> millions of older systems run >fine without them.
As do many newer systems, too, but this alone is, at best, a specious argument against WDTs. BTW, the product to which I refer is the control panels for the 440 line of video/audio/timecode routing switchers produced by Grass Valley Group for the television broadcast industry. These were 8048-based, developed on 8080-based Intel MDS-230 (Blue Box!) development systems, and communicated serially with Z80-based controllers. I miss those days, not so much for the processors and tools but because the economics at that time allowed engineers, rather than accountants, to call the product development shots. -- ======================================================================== Michael Kesti | "And like, one and one don't make | two, one and one make one." mkesti@gv.net | - The Who, Bargain
"Michael R. Kesti" <mkesti@gv.net> wrote in message
news:40B4C4BE.1451E58B@gv.net...
> BTW, the product to which I refer is the control panels for the 440 line > of video/audio/timecode routing switchers produced by Grass Valley Group > for the television broadcast industry. These were 8048-based, developed > on 8080-based Intel MDS-230 (Blue Box!) development systems, and > communicated serially with Z80-based controllers.
Ah... the Intel MDS <sigh of nostalgia>. I still miss the editor, CREDIT... Around '83 I used to tote around the MDS's little brother, the iPDS... which had 5-1/4" disks - whoa! radical!
> I miss those days, not > so much for the processors and tools but because the economics at that
time
> allowed engineers, rather than accountants, to call the product
development
> shots.
Errr... yeah, but do you remember how much those suckers used to cost? I think the iPDS cost us (with ICE, which was around half of the total, IIRC) around 13 kilobucks... Back then development systems were major capital investment. Nowadays it's a PC and GNU ;). Steve http://www.sfdesign.co.uk http://www.fivetrees.com
On Wed, 26 May 2004 17:12:46 +0100, "Steve at fivetrees"
<steve@NOSPAMTAfivetrees.com> wrote:

>"CBarn24050" <cbarn24050@aol.com> wrote in message >news:20040526113523.17668.00001101@mb-m15.aol.com... >> > >> >Watchdogs are not there to protect against dodgy code and/or unduly >> >"vulnerable" hardware. They're there because, ultimately, *all* hardware >is >> >vulnerable. It's just a question of degree. If you don't believe me, >equip >> >yourself with a Schaffner and try dumping a fast-rise time 2kV spike into >> >nearby metalwork... >> >> The watchdog timer is a fairly recent invention, millions of older systems >run >> fine without them. > >It's exactly as old as embedded microprocessors. (I know. I was there.) It's >dumb having one without the other. >
No, it's much older than embedded microprocessors. -- Al Balmer Balmer Consulting removebalmerconsultingthis@att.net
On 26 May, in article
     <20040526113523.17668.00001101@mb-m15.aol.com>
     cbarn24050@aol.com "CBarn24050" wrote:
>>Watchdogs are not there to protect against dodgy code and/or unduly >>"vulnerable" hardware. They're there because, ultimately, *all* hardware is >>vulnerable. It's just a question of degree. If you don't believe me, equip >>yourself with a Schaffner and try dumping a fast-rise time 2kV spike into >>nearby metalwork... > >The watchdog timer is a fairly recent invention, millions of older systems run >fine without them.
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 | paul@pcserv.demon.co.uk <http://www.pcserv.demon.co.uk/> Main Site <http://www.gnuh8.org.uk/> GNU H8 & mailing list info. <http://www.badweb.org.uk/> For those web sites you hate.
"Alan Balmer" <albalmer@att.net> wrote in message
news:5vk9b01keq1rqhj1ti2vdh8eqpailpkbqn@4ax.com...
> >> The watchdog timer is a fairly recent invention, millions of older
systems
> >run > >> fine without them. > > > >It's exactly as old as embedded microprocessors. (I know. I was there.)
It's
> >dumb having one without the other. > > > No, it's much older than embedded microprocessors.
I'm intrigued! I only came across them in the context of embedded micros (late '70s), but on reflection I can imagine they'd be useful thingies in non-embedded contexts. However, I presume still within the realms of hardware/software integration? Pray tell! Steve http://www.sfdesign.co.uk http://www.fivetrees.com
On Wed, 26 May 2004 20:01:46 +0100, "Steve at fivetrees"
<steve@NOSPAMTAfivetrees.com> wrote:

>"Alan Balmer" <albalmer@att.net> wrote in message >news:5vk9b01keq1rqhj1ti2vdh8eqpailpkbqn@4ax.com... >> >> The watchdog timer is a fairly recent invention, millions of older >systems >> >run >> >> fine without them. >> > >> >It's exactly as old as embedded microprocessors. (I know. I was there.) >It's >> >dumb having one without the other. >> > >> No, it's much older than embedded microprocessors. > >I'm intrigued! I only came across them in the context of embedded micros >(late '70s), but on reflection I can imagine they'd be useful thingies in >non-embedded contexts. However, I presume still within the realms of >hardware/software integration? Pray tell!
We used them in the mid to late 60's on process control systems. On a dual system, the watchdog did two things - it switched the process control bus to the backup computer and rebooted it. The control database was piped once per second from the control computer to the backup on a high-speed core-to-core link, and the reboot took less than a second. This was from a head-per-track disk, and the biggest system had a whole megabyte of memory, so it didn't take long :-) On single-processor systems, we sometimes used a sort of long-period mechanical watchdog. If there was a power interruption, the system would recover when power was restored, and the watchdog would enable the decision as to whether to pick up the process where it left off, or stay in failsafe and yell for an operator. -- Al Balmer Balmer Consulting removebalmerconsultingthis@att.net
On Wed, 26 May 2004 17:37:52 +0100, "Steve at fivetrees"
<steve@NOSPAMTAfivetrees.com> wrote:
[...]
>Ah... the Intel MDS <sigh of nostalgia>. I still miss the editor, CREDIT...
It wasn't a bad editor at the time. I liked it so much, I wrote a paper for my employer using it. This was back in the day when SOP was to write it out longhand and hand the chicken scratch to a secretary. This was also before I got used to Windoze and computers that crashed, so I spent about 3 hours on it before trying to save it. Unfortunately, I made a typo and tried to save the file to the system disk -- which was full. "Insufficient space" error message followed by -- the ISIS prompt. Game over. Thanks for playing. Aargh. The second version of the paper only took about an hour and a half, and was probably better overall. But I learned my lesson (one of them anyway). Regards, -=Dave -- Change is inevitable, progress is not.
"Alan Balmer" <albalmer@att.net> wrote in message
news:bpq9b01m8va4ss24s9p6d7jgrtkv3alvvi@4ax.com...
> We used them in the mid to late 60's on process control systems. On a > dual system, the watchdog did two things - it switched the process > control bus to the backup computer and rebooted it. The control > database was piped once per second from the control computer to the > backup on a high-speed core-to-core link, and the reboot took less > than a second. This was from a head-per-track disk, and the biggest > system had a whole megabyte of memory, so it didn't take long :-)
Impressive!
> On single-processor systems, we sometimes used a sort of long-period > mechanical watchdog. If there was a power interruption, the system > would recover when power was restored, and the watchdog would enable > the decision as to whether to pick up the process where it left off, > or stay in failsafe and yell for an operator.
My main background is also in process control (mainly temperature control). From working in Chicago in the early 80s I recall that "watchdogs" (or was it "policemen"?) were mandatory (insurance-wise) on certain processes in certain states, but these were simply over-temperature/pressure failsafes... or have I got that all backwards? A lot of neurons have flowed under the bridge since... Steve (older, wiser, balder) http://www.sfdesign.co.uk http://www.fivetrees.com
"Dave Hansen" <iddw@hotmail.com> wrote in message
news:40b4ee34.151436706@News.individual.net...
> On Wed, 26 May 2004 17:37:52 +0100, "Steve at fivetrees" > <steve@NOSPAMTAfivetrees.com> wrote: > [...] > >Ah... the Intel MDS <sigh of nostalgia>. I still miss the editor,
CREDIT...
> > It wasn't a bad editor at the time. I liked it so much, I wrote a > paper for my employer using it. This was back in the day when SOP was > to write it out longhand and hand the chicken scratch to a secretary.
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