| Author |
Message |
glen herrmannsfeldt
Guest
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 Posted:
Sat Jan 29, 2005 1:00 am Post subject:
Re: Relocating application architecture and compiler support |
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CBFalconer wrote:
(snip)
| Quote: | People who program your microwave, or even your famous RFI
generating stove, are not likely to be worried about dynamically
relocatable code on system 360, or even on a PDP10. They are
worried about where to get a ten cent chip to handle talking
Barbies, etc.
|
I think you are right, but much of the problem with OS/360 was
getting all the features (remember the second system effect)
into a small (compared to today) memory.
Embedded systems still have small RAMs, so there might be
some things to learn. On the other hand, not having a disk
will make much of it less applicable.
The 2K transient areas were one solution to the "whole OS
won't fit into memory" problem, one that MS doesn't seem to
be worried about.
-- glen |
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Morten Reistad
Guest
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| Posted:
Sat Jan 29, 2005 1:31 am Post subject:
Re: Relocating application architecture and compiler support |
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In article <cte5ha$iki$1@gemini.csx.cam.ac.uk>,
Nick Maclaren <nmm1@cus.cam.ac.uk> wrote:
| Quote: | In article <41FA8EFF.1B63B6B2@yahoo.com>,
CBFalconer <cbfalconer@worldnet.att.net> wrote:
jmfbahciv@aol.com wrote:
CBFalconer <cbfalconer@yahoo.com> wrote:
jmfbahciv@aol.com wrote:
Where are you posting from? There's been a complaint about
posting this to c.a.e. And I always get kicked out of c.a.
This is all OT on comp.arch.embedded. Please set followups on any
further entries in this thread to eliminate c.a.e.
And the heavens forbid that people who only read c.a.e. find out
about problems they may have to think about some time.
People who program your microwave, or even your famous RFI
generating stove, are not likely to be worried about dynamically
relocatable code on system 360, or even on a PDP10. They are
worried about where to get a ten cent chip to handle talking
Barbies, etc.
|
Those who forget history's mistakes are bound to repeat them.
It is ironic, because many embedded os'es have a lot in common
with tops10 design-wise, and show a clear heritage.
| Quote: | Try reading what was posted again, carefully. Then think about it.
In particular, contemplate:
1) Not everyone writing embedded codes is writing joke ones;
some people are doing heavyweight tasks, like controlling aircraft
or chemical plants.
|
I don't consider controlling a kilowatt of radiation a joke
application. Nor is the control of a stove and other stuff that
can burn down a house if it malfunctions the wrong way.
| Quote: |
2) There is an increasing trend to use general purpose hardware
and software for embedded work, so knowing about goes on there is a
potential advantage.
3) The techniques for dynamic relocation are quite important for
high-reliability codes, where you may want to move running code from
a failing CPU to a backup one.
|
-- amen. |
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Nick Maclaren
Guest
|
| Posted:
Sat Jan 29, 2005 1:43 am Post subject:
Re: Relocating application architecture and compiler support |
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In article <pr6etc.3id.ln@via.reistad.priv.no>,
Morten Reistad <firstname@lastname.pr1v.n0> wrote:
| Quote: |
1) Not everyone writing embedded codes is writing joke ones;
some people are doing heavyweight tasks, like controlling aircraft
or chemical plants.
I don't consider controlling a kilowatt of radiation a joke
application. Nor is the control of a stove and other stuff that
can burn down a house if it malfunctions the wrong way.
|
Compared with controlling a chemical plant, it is. Compare the common
cases of electrical faults causing house fires with Bhopal.
But I think that we are agreed that even small scale embedded coding
should not be treated as a joke, i.e. where mistakes don't matter, even
if you can usually get away with it. However, you CAN afford to take
the trivial approach that you shut down on any problem, and leave the
user to restart the system. In that sense, they don't need anything
more than a joke operating system - UNLIKE chemical plants.
Regards,
Nick Maclaren. |
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Peter Flass
Guest
|
| Posted:
Sat Jan 29, 2005 6:48 am Post subject:
Re: Relocating application architecture and compiler support |
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Stephen Fuld wrote:
| Quote: | jmfbahciv@aol.com> wrote in message news:KtudnRP6wN8T1WfcRVn-sQ@rcn.net...
In article <41f948f4$1@ibixwebf.ibi.com>,
Edward Wolfgram <Not_Edward_Wolfgram@notiwaysoftware.com> wrote:
snip
..Thus, at an
interruption, we can swap a user's context (program and data) at will to
another location in memory.
Nope that (swap) takes too long. At monitor that knows its job
will store the address of the user's page map page on its stack.
If the data and/or program needs to be moved or swapped for
any reason, this work is done once the interrupt is dismissed.
I don't think it's ever done at interrupt level...I can't think
of a scenario when swap and/or moving is done. In the computing
biz, there is always an exception to every rule...including this
one :-).
Of course. :-) Actually, it is quite frequent. Consider a time sharing
system where the user program does a request for input from the human at the
terminal. There is an interrupt of the user program from the kernel
request, and it makes sense to swap the program out for what is probably at
least seconds of user think time if there are other user program waiting to
gain access to memory. When the human responds and it is time to swap the
program back in, you don't want to be constrained to swap it in at the same
physical location from where it was swapped out.
|
I think this is what OS/360 MVT ROLLIN/ROLLOUT did. Probably why no one
used it much AFAIK. |
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Guest
|
| Posted:
Sat Jan 29, 2005 4:43 pm Post subject:
Re: Relocating application architecture and compiler support |
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In article <pr6etc.3id.ln@via.reistad.priv.no>,
Morten Reistad <firstname@lastname.pr1v.n0> wrote:
| Quote: | In article <cte5ha$iki$1@gemini.csx.cam.ac.uk>,
Nick Maclaren <nmm1@cus.cam.ac.uk> wrote:
In article <41FA8EFF.1B63B6B2@yahoo.com>,
CBFalconer <cbfalconer@worldnet.att.net> wrote:
jmfbahciv@aol.com wrote:
CBFalconer <cbfalconer@yahoo.com> wrote:
jmfbahciv@aol.com wrote:
Where are you posting from? There's been a complaint about
posting this to c.a.e. And I always get kicked out of c.a.
This is all OT on comp.arch.embedded. Please set followups on any
further entries in this thread to eliminate c.a.e.
And the heavens forbid that people who only read c.a.e. find out
about problems they may have to think about some time.
People who program your microwave, or even your famous RFI
generating stove, are not likely to be worried about dynamically
relocatable code on system 360, or even on a PDP10. They are
worried about where to get a ten cent chip to handle talking
Barbies, etc.
Those who forget history's mistakes are bound to repeat them.
It is ironic, because many embedded os'es have a lot in common
with tops10 design-wise, and show a clear heritage.
Try reading what was posted again, carefully. Then think about it.
In particular, contemplate:
1) Not everyone writing embedded codes is writing joke ones;
some people are doing heavyweight tasks, like controlling aircraft
or chemical plants.
I don't consider controlling a kilowatt of radiation a joke
application. Nor is the control of a stove and other stuff that
can burn down a house if it malfunctions the wrong way.
2) There is an increasing trend to use general purpose hardware
and software for embedded work, so knowing about goes on there is a
potential advantage.
3) The techniques for dynamic relocation are quite important for
high-reliability codes, where you may want to move running code from
a failing CPU to a backup one.
-- amen.
Thank you, both. Note that this didn't make it into c.a.e. |
/BAH
Subtract a hundred and four for e-mail. |
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Stephen Fuld
Guest
|
| Posted:
Sun Jan 30, 2005 7:55 am Post subject:
Re: Relocating application architecture and compiler support |
|
|
"Peter Flass" <Peter_Flass@Yahoo.com> wrote in message
news:wXBKd.10313$MX2.4511@twister.nyroc.rr.com...
| Quote: | Stephen Fuld wrote:
jmfbahciv@aol.com> wrote in message
news:KtudnRP6wN8T1WfcRVn-sQ@rcn.net...
In article <41f948f4$1@ibixwebf.ibi.com>,
Edward Wolfgram <Not_Edward_Wolfgram@notiwaysoftware.com> wrote:
snip
..Thus, at an
interruption, we can swap a user's context (program and data) at will to
another location in memory.
Nope that (swap) takes too long. At monitor that knows its job
will store the address of the user's page map page on its stack.
If the data and/or program needs to be moved or swapped for
any reason, this work is done once the interrupt is dismissed.
I don't think it's ever done at interrupt level...I can't think
of a scenario when swap and/or moving is done. In the computing
biz, there is always an exception to every rule...including this
one :-).
Of course. :-) Actually, it is quite frequent. Consider a time sharing
system where the user program does a request for input from the human at
the terminal. There is an interrupt of the user program from the kernel
request, and it makes sense to swap the program out for what is probably
at least seconds of user think time if there are other user program
waiting to gain access to memory. When the human responds and it is time
to swap the program back in, you don't want to be constrained to swap it
in at the same physical location from where it was swapped out.
I think this is what OS/360 MVT ROLLIN/ROLLOUT did. Probably why no one
used it much AFAIK.
|
Precisely! The limitation of having to be rolled back in to the same
physical location from which it was rolled out made it almost useless. That
is why having the features I described early in this thread, which were not
in S/360 hardware were such an advantage.
--
- Stephen Fuld
e-mail address disguised to prevent spam |
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Dan Koren
Guest
|
| Posted:
Mon Jan 31, 2005 7:56 am Post subject:
Re: Relocating application architecture and compiler support |
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|
"Nick Maclaren" <nmm1@cus.cam.ac.uk> wrote in message
news:cte84t$nt0$1@gemini.csx.cam.ac.uk...
| Quote: |
But I think that we are agreed that
even small scale embedded coding
should not be treated as a joke,
i.e. where mistakes don't matter,
even if you can usually get away
with it.
|
*NO* coding should be treated as a joke.
One should treat every byte one writes
as a matter of life and death.
dk |
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Nick Maclaren
Guest
|
| Posted:
Mon Jan 31, 2005 2:19 pm Post subject:
Re: Relocating application architecture and compiler support |
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|
In article <41fde33b$1@news.meer.net>, Dan Koren <dankoren@yahoo.com> wrote:
| Quote: | "Nick Maclaren" <nmm1@cus.cam.ac.uk> wrote in message
news:cte84t$nt0$1@gemini.csx.cam.ac.uk...
But I think that we are agreed that
even small scale embedded coding
should not be treated as a joke,
i.e. where mistakes don't matter,
even if you can usually get away
with it.
*NO* coding should be treated as a joke.
One should treat every byte one writes
as a matter of life and death.
|
There are only 24 hours in a day, you know.
I agree with you that should be a target, but not one that should
necessarily be more than aimed towards. It would be better if a few
more utilities (such as compilers) took on board that they can become
critical when they are used as a component for something critical.
Regards,
Nick Maclaren. |
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Terje Mathisen
Guest
|
| Posted:
Mon Jan 31, 2005 3:25 pm Post subject:
Re: Relocating application architecture and compiler support |
|
|
Dan Koren wrote:
| Quote: | "Nick Maclaren" <nmm1@cus.cam.ac.uk> wrote in message
news:cte84t$nt0$1@gemini.csx.cam.ac.uk...
But I think that we are agreed that
even small scale embedded coding
should not be treated as a joke,
i.e. where mistakes don't matter,
even if you can usually get away
with it.
*NO* coding should be treated as a joke.
|
Agreed.
| Quote: |
One should treat every byte one writes
as a matter of life and death.
|
That, in my not so humble opinion, is rubbish, and you almost certainly
know it.
Terje
--
- <Terje.Mathisen@hda.hydro.com>
"almost all programming can be viewed as an exercise in caching" |
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Dan Koren
Guest
|
| Posted:
Mon Jan 31, 2005 4:05 pm Post subject:
Re: Relocating application architecture and compiler support |
|
|
"Terje Mathisen" <terje.mathisen@hda.hydro.com> wrote in message
news:ctl128$dj$2@osl016lin.hda.hydro.com...
| Quote: | Dan Koren wrote:
"Nick Maclaren" <nmm1@cus.cam.ac.uk> wrote in message
news:cte84t$nt0$1@gemini.csx.cam.ac.uk...
But I think that we are agreed that
even small scale embedded coding
should not be treated as a joke,
i.e. where mistakes don't matter,
even if you can usually get away
with it.
*NO* coding should be treated as a joke.
Agreed.
One should treat every byte one writes
as a matter of life and death.
That, in my not so humble opinion, is
rubbish,
|
It is not.
| Quote: | and you almost certainly know it.
|
No, I don't. I spent the early years
of my career writing OS's for hard
real time mission critical systems
-- *truly* mission critical as in
"aircraft might fall off the sky"
if the systems underperforms (let
alone malfunctions). And I take my
responsibility as seriously as a
cardiac or neuro surgeon. Do you?
dk |
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Nick Maclaren
Guest
|
| Posted:
Mon Jan 31, 2005 5:01 pm Post subject:
Re: Relocating application architecture and compiler support |
|
|
In article <41fe1269$1@news.meer.net>,
"Dan Koren" <dankoren@yahoo.com> writes:
|> "Terje Mathisen" <terje.mathisen@hda.hydro.com> wrote in message
|> news:ctl128$dj$2@osl016lin.hda.hydro.com...
|> > Dan Koren wrote:
|> >
|> > > One should treat every byte one writes
|> > > as a matter of life and death.
|> >
|> > That, in my not so humble opinion, is
|> > rubbish,
|>
|> It is not.
|>
|> > and you almost certainly know it.
|>
|> No, I don't. I spent the early years
|> of my career writing OS's for hard
|> real time mission critical systems
|> -- *truly* mission critical as in
|> "aircraft might fall off the sky"
|> if the systems underperforms (let
|> alone malfunctions). And I take my
|> responsibility as seriously as a
|> cardiac or neuro surgeon. Do you?
And not all coding is like that. I write a fair number
of one-off programs to check out some aspect of a system,
fix something up that I am going to check manually and so
on. Should I really worry about getting every last bug
out of those programs?
Regards,
Nick Maclaren. |
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Guest
|
| Posted:
Mon Jan 31, 2005 5:25 pm Post subject:
Re: Relocating application architecture and compiler support |
|
|
In article <ctl128$dj$2@osl016lin.hda.hydro.com>,
Terje Mathisen <terje.mathisen@hda.hydro.com> wrote:
| Quote: | Dan Koren wrote:
"Nick Maclaren" <nmm1@cus.cam.ac.uk> wrote in message
news:cte84t$nt0$1@gemini.csx.cam.ac.uk...
But I think that we are agreed that
even small scale embedded coding
should not be treated as a joke,
i.e. where mistakes don't matter,
even if you can usually get away
with it.
*NO* coding should be treated as a joke.
Agreed.
One should treat every byte one writes
as a matter of life and death.
That, in my not so humble opinion, is rubbish, and you almost certainly
know it.
|
Pride might be better.
/BAH
Subtract a hundred and four for e-mail. |
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Terje Mathisen
Guest
|
| Posted:
Mon Jan 31, 2005 6:24 pm Post subject:
Re: Relocating application architecture and compiler support |
|
|
Dan Koren wrote:
| Quote: | "Terje Mathisen" <terje.mathisen@hda.hydro.com> wrote in message
news:ctl128$dj$2@osl016lin.hda.hydro.com...
Dan Koren wrote:
One should treat every byte one writes
as a matter of life and death.
That, in my not so humble opinion, is
rubbish,
It is not.
and you almost certainly know it.
No, I don't. I spent the early years
of my career writing OS's for hard
real time mission critical systems
-- *truly* mission critical as in
"aircraft might fall off the sky"
if the systems underperforms (let
alone malfunctions). And I take my
responsibility as seriously as a
cardiac or neuro surgeon. Do you?
|
Yes, I believe I do.
I still write quite a bit of throw-away (use-once) code though, i.e. in
the form of perl one-liners.
I do not treat this in the same way as when I write code where a bug
could (probably would!) bankrupt the company my wife's grandfather started.
The only way your statement makes sense to me would be if you _only_
write (at least potentially) mission critical code. Do you?
Terje
--
- <Terje.Mathisen@hda.hydro.com>
"almost all programming can be viewed as an exercise in caching" |
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Duane Rettig
Guest
|
| Posted:
Mon Jan 31, 2005 10:18 pm Post subject:
Re: Relocating application architecture and compiler support |
|
|
"Dan Koren" <dankoren@yahoo.com> writes:
| Quote: | "Terje Mathisen" <terje.mathisen@hda.hydro.com> wrote in message
news:ctl128$dj$2@osl016lin.hda.hydro.com...
Dan Koren wrote:
"Nick Maclaren" <nmm1@cus.cam.ac.uk> wrote in message
news:cte84t$nt0$1@gemini.csx.cam.ac.uk...
But I think that we are agreed that
even small scale embedded coding
should not be treated as a joke,
i.e. where mistakes don't matter,
even if you can usually get away
with it.
*NO* coding should be treated as a joke.
Agreed.
One should treat every byte one writes
as a matter of life and death.
That, in my not so humble opinion, is
rubbish,
It is not.
and you almost certainly know it.
No, I don't. I spent the early years
of my career writing OS's for hard
real time mission critical systems
-- *truly* mission critical as in
"aircraft might fall off the sky"
if the systems underperforms (let
alone malfunctions). And I take my
responsibility as seriously as a
cardiac or neuro surgeon. Do you?
|
I understand and agree with your general sentiment; many programmers
don't take their programming seriously enough. However, even a cardiac
surgeon is not "on" 24/7, and certainly need not take the same care
in extracting a sliver from his skin as he does in sewing up heart
tissue (for one thing, he won't surround himself with nurses and an
anesthesiologist for the former :-)
--
Duane Rettig duane@franz.com Franz Inc. http://www.franz.com/
555 12th St., Suite 1450 http://www.555citycenter.com/
Oakland, Ca. 94607 Phone: (510) 452-2000; Fax: (510) 452-0182 |
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Mabden
Guest
|
| Posted:
Tue Feb 01, 2005 6:14 am Post subject:
Re: Relocating application architecture and compiler support |
|
|
"Dan Koren" <dankoren@yahoo.com> wrote in message
news:41fe1269$1@news.meer.net...
| Quote: |
"Terje Mathisen" <terje.mathisen@hda.hydro.com> wrote in message
news:ctl128$dj$2@osl016lin.hda.hydro.com...
Dan Koren wrote:
"Nick Maclaren" <nmm1@cus.cam.ac.uk> wrote in message
news:cte84t$nt0$1@gemini.csx.cam.ac.uk...
But I think that we are agreed that
even small scale embedded coding
should not be treated as a joke,
i.e. where mistakes don't matter,
even if you can usually get away
with it.
*NO* coding should be treated as a joke.
Agreed.
One should treat every byte one writes
as a matter of life and death.
That, in my not so humble opinion, is
rubbish,
It is not.
and you almost certainly know it.
No, I don't. I spent the early years
of my career writing OS's for hard
real time mission critical systems
-- *truly* mission critical as in
"aircraft might fall off the sky"
if the systems underperforms (let
alone malfunctions). And I take my
responsibility as seriously as a
cardiac or neuro surgeon. Do you?
|
Well, my tile game uses a simple "shuffle" routine that I've never even
examined once. I just run through all the tiles and randomly place them
in "the bag". If it isn't a good function then I guess my game might
generate the same tile set twice. So far I haven't noticed it happening,
tho. One day I should look into "proving" it is not omitting some
combinations, or repeating some. But, hey, it's only a tile game, NOT a
matter of life and death. OH it's for the Palm OS and it's free here:
http://www.sitenook.com/Games/PARishido.zip
--
Mabden |
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