The Massachusetts case has nothing to do with the quality of software, its about policy makers making broad rules based on ideology without regard to the specific needs of individuals and organizations.
Saying that real-time software was completely dead was perhaps overstating the case, but I think the use of dedicated microcontrollers implementing a single function and specialized hardware has made the programming effort less complex than in the past. That's as it should be.
A single microcontroller in car probably represents less than.1% of the overall cost. Why not have more than one and improve the safety and lower the cost of developing the software?
My point was that less hard real-time software is being written today relative to non-real-time software than 10 or 20 years ago. I don't know the details of the software running in cars but I doubt that it's hard real-time. The fact that you used the word micro-processor rather than microcontroller suggests to me that you may not be all that knowledgeable about it either. If you are, then maybe you could expand on the details a bit.
"How about if you try to look into facts before shooting your mouth off?"
I'm not an expert in RT java, but I've written code with required timing accuracy to 1 cpu cycle which I think qualifies me quite well to comment on RT issues.
"What's important is that if you have a specific architecture you need to know, exactly, what delays occur and that they have upper bounds."
The issue isn't speed, it's accuracy. Hard RT systems have lower bounds as well as upper bounds. Being early is no better than being late.
"The same would be true with a Asm or C RT system"
Sure, but the difference is that in Java you have another layer to deal with so determining the timing is more complex.
"The main reason you'd want to run Java RT is because first off, it's faster to write correctly."
This is a matter of opinion even for conventional programs. For a RT system, I think you have the burden of proof for this claim.
"Yeah, like Google, who runs a custom Linux kernel. Sure would be nice to get ahold of that."
Yes, I'm sure Google has put the word out that they have a custom Linux kernel and it's really, really great. I doubt that it has broad appeal or that it does something nobody else can do.
"because with linux, all improvements are available to all whereas with bsds they can be taken away and nobody will be able to takes advantage of it. "
You're wrong. Not all improvements to Linux will be available since not all of the modified code is distributed. No BSD code can every be taken away, only the private modifications people make.
I think this "improvements" argument isn't a very strong one anyway. I'll bet that most of them will never appear in a major distribution.
"As the name suggests, it was IBM who first started building standardised desktops and letting others in on the standards in question."
This is revisionist history. It took years for other vendors to be able to clone the non-OS part of the PC. It would have taken many more years to make a viable clone if the vendors had not been able to buy the OS from MS.
IBM introduced the PS/2 computer line (with its proprietary Micro Channel bus architecture) specifically to gain back the market share lost to the clones. Hardly the behavior of a company that wanted to be totally open.
I think the term "distribution" is quite open to interpretation by the courts. Is it a distribution if I distribute it to a coworker or a friend? What about my parent company? Can somebody start a Screw-the-GPL club where they modify GPL'd software and give it only to club members so they don't really distribute it?
I think the real purpose of putting this in the GPL is to sucker people into GPLing their own code. If you create something really useful internally and GPL fanatics get wind of it, you can bet their intrepretation of distribution will be very broad.
The problem with a simple loop is that you often end up with timing relationships between functions that are really arbitrary ("Function A occurs on every interrupt. Let's make function B happen every 10 times function A occurs by having it run once every 10 loops. That's probably about right"). Then you find out that later that you need to change the timing for function A and now the timing for function B is off.
When of the main benefits of an RTOS is modularizing time. The only timing relationships between tasks are those you create.
Real-time software isn't even necessarily processor speed-independent, let alone platform dependent.
In the worst case, you have to know exactly how many time (accurate to the length of a CPU cycle) it will take for a section of code to be executed or know exactly how long it will take an interrupt to vector to your interrupt handler.
I'll be Java timing isn't even consistent from one JVM release to the next for the same code running on the same computer.
I think as long as you're talking about the "new" embedded systems (i.e. no or easy real-time or a general purpose computer in a smaller form-factor) then OS's like Windows CE or Linux will be OK.
For traditional embedded systems (i.e extremely limited resources or true real-time software) these OS's will come up short. They are too bloated for low resources systems and their timing is to variable for serious real-time work.
Of course, most of today's microprocessors aren't appropriate for hard real-time software either. Once you add complicated prefetch schemes and caches to the mix, you can't really do anything that requires fine timing precision.
Fortunately for traditional OS's, real-time software is a dying art and most real-time work is done in specialized hardware rather than software these days. In addition, the resource issue is not really much of a problem these days.
"Let programers do what they want. " "thats great, assuming they all want to do it the same way."
Why should they all do it the same way? The argument typically advanced by those promoting coding standards is that they make the code easier to understand. If a programmer is going to be scratching his head because he's unfamiliar with the naming convention, he's certainly not going to be able handle C/C++ pointers or Java generics.
In truth understandability is really just an excuse. The main motivation for coding standards are power and a compulsive need to produce order where none is required. In practice, a manager or the "alpha" programmer dictates the bulk of the standard that everyone else has to live with. It's very rare that the process is democratic.
The fact that holograms haven't taken over photographs has nothing to do with people's preferences for 2D over 3D. It's because of the expense, lack of true color and the fact that people can't stand still that long. If you could point and shoot a hologram with full color using normal exposure speeds and the camera was less than $500, they'd be selling faster than iPods.
Holograms also solve the focus issue since they reproduce the wavefront that came from the original scene.
"Better from a technological standpoint, yes, but logistically impossible... but I'm afraid HTTP/HTML/CSS/Javascript is far too ingrained for that. "
On the other hand, consider how ingrained desktop applications were prior to the WWW. History is littered with the remains of technologies that are "too ingrained" to be replaced.
Let's face it though. Javascript is hack to make a web-based document viewing technology into an interactive one. It would be far better to upgrade HTTP and HTML to natively support the functionality that all interactive web-apps need then to download the same boiler-plate javascript code trillions of times forever and ever.
"They really would prefer that they be the gateway to the web and that you pay $$$ to them to be able to get the content as well as selling their OS. AJAX makes windows less relevant because you can run apps on firefox on any platform."
Sure, AJAX technology detects if you're charging for your web app and shuts down immediately if you are.
Seriously, there's no relationship between the type of technology you use for your application and your ability to charge for it.
I think we've already gone too far in our pursuit of portable code.
Look at Java threading. You have to use synchronization to protect your thread against being preempted, while yielding to protect all the other threads in case you never are.
That's because the underlying process and thread models used by different OS can't be abstracted away in single model. So you end up with very little thread behavior that you can count on.
Cross-platform code will always be more complex and less satisfying than targeting a particular platform.
"They are perfectly fine analogies. If there's a flaw, why don't you point it out instead of dismissing them off hand as "straw"?"
Sure. First of all we are talking about a decade of financial transactions over the Internet (at the most). Not 50 years, not hundreds of years, but only 10 years. In addition while connecting all the networks together provides some value, that value is not remotely comparable to the difference between doing calculations by hand vs. with a computer. There are also real-time use of computers that simply could not be done by hand at all. The difference between pre-Internet financial transaction capability and post-Internet financial transaction capablitity is negligable by comparison.
"Just as you made a "general observation" about how "young people" experience the world, I made one about old people, one which resonates well with how many old people react to new technology."
What you actually said "you're too old to realize just how much things have changed since you were young" which is not a comment on how old people react to new technology. But hey, don't let facts get in your way.
"You have presented absolutely zero evidence in favor of your position, only vague allusions to "it worked before" which are completely irrelevant, as several people have already pointed out."
So you don't think that "it worked before without it" is relevant to a discussion on the effects of removing something. Then what, pray tell, could possibly be relevant?
"Insulting the parent poster implying that his stance is the result of youth puts you in a very poor light, especially since you're so obviously wrong"
There was no insult involved, just the observation that it's difficult for those that haven't lived under different conditions to imagine what it was like. It was true for your parents, it's true for you, and it will be true for your children.
"Guns aren't necessary to the operation of national defense..." "Computers aren't necessary to the operation of financial institutions"
Thanks for the straw arguments.
"I could write a thousand word post about the immense havoc that immediately would ensure if the Internet disappeared, but what's the use?"
Hey, if you don't want to write a thousand words, why bother writing any, right?
"you're too old to realize just how much things have changed since you were young"
What happened to your concern about insults? It's not an insult to suggest that someone who didn't live through a particular era might not understand it, it is an insult to suggest that someone who is older has been asleep for the last decade.
I suspect you're fairly young and have a great interest in technology. Thus the consequences seem more dire to you than to those who have lived longer under a pre-Internet society and have no special interest.
The Internet as we know it is not really necessary to the operation of financial institutions, education, and national defense. In fact one could argue that the Internet has made financial transactions more vunerable, and has been more of a distraction to students than a research tool.
Hey, they say the French love Jerry Lewis which I don't get, but they sure as hell were a lot smarter than the average US citizen when it came to WMDs in Iraq.
Hell, about 30% of Americans still believe that there are WMDs in Iraq, so I don't think we should be lecturing the French until we admit we were wrong.
Slashdot Mirror
The Massachusetts case has nothing to do with the quality of software, its about policy makers making broad rules based on ideology without regard to the specific needs of individuals and organizations.
Saying that real-time software was completely dead was perhaps overstating the case, but I think the use of dedicated microcontrollers implementing a single function and specialized hardware has made the programming effort less complex than in the past. That's as it should be.
.1% of the overall cost. Why not have more than one and improve the safety and lower the cost of developing the software?
A single microcontroller in car probably represents less than
My point was that less hard real-time software is being written today relative to non-real-time software than 10 or 20 years ago. I don't know the details of the software running in cars but I doubt that it's hard real-time. The fact that you used the word micro-processor rather than microcontroller suggests to me that you may not be all that knowledgeable about it either. If you are, then maybe you could expand on the details a bit.
"How about if you try to look into facts before shooting your mouth off?"
I'm not an expert in RT java, but I've written code with required timing accuracy to 1 cpu cycle which I think qualifies me quite well to comment on RT issues.
"What's important is that if you have a specific architecture you need to know, exactly, what delays occur and that they have upper bounds."
The issue isn't speed, it's accuracy. Hard RT systems have lower bounds as well as upper bounds. Being early is no better than being late.
"The same would be true with a Asm or C RT system"
Sure, but the difference is that in Java you have another layer to deal with so determining the timing is more complex.
"The main reason you'd want to run Java RT is because first off, it's faster to write correctly."
This is a matter of opinion even for conventional programs. For a RT system, I think you have the burden of proof for this claim.
"Yeah, like Google, who runs a custom Linux kernel. Sure would be nice to get ahold of that."
Yes, I'm sure Google has put the word out that they have a custom Linux kernel and it's really, really great. I doubt that it has broad appeal or that it does something nobody else can do.
"because with linux, all improvements are available to all whereas with bsds they can be taken away and nobody will be able to takes advantage of it. "
You're wrong. Not all improvements to Linux will be available since not all of the modified code is distributed. No BSD code can every be taken away, only the private modifications people make.
I think this "improvements" argument isn't a very strong one anyway. I'll bet that most of them will never appear in a major distribution.
"As the name suggests, it was IBM who first started building standardised desktops and letting others in on the standards in question."
This is revisionist history. It took years for other vendors to be able to clone the non-OS part of the PC. It would have taken many more years to make a viable clone if the vendors had not been able to buy the OS from MS.
IBM introduced the PS/2 computer line (with its proprietary Micro Channel bus architecture) specifically to gain back the market share lost to the clones. Hardly the behavior of a company that wanted to be totally open.
I think the term "distribution" is quite open to interpretation by the courts. Is it a distribution if I distribute it to a coworker or a friend? What about my parent company? Can somebody start a Screw-the-GPL club where they modify GPL'd software and give it only to club members so they don't really distribute it?
I think the real purpose of putting this in the GPL is to sucker people into GPLing their own code. If you create something really useful internally and GPL fanatics get wind of it, you can bet their intrepretation of distribution will be very broad.
You're right in some cases.
The problem with a simple loop is that you often end up with timing relationships between functions that are really arbitrary ("Function A occurs on every interrupt. Let's make function B happen every 10 times function A occurs by having it run once every 10 loops. That's probably about right"). Then you find out that later that you need to change the timing for function A and now the timing for function B is off.
When of the main benefits of an RTOS is modularizing time. The only timing relationships between tasks are those you create.
Real-time software isn't even necessarily processor speed-independent, let alone platform dependent.
In the worst case, you have to know exactly how many time (accurate to the length of a CPU cycle) it will take for a section of code to be executed or know exactly how long it will take an interrupt to vector to your interrupt handler.
I'll be Java timing isn't even consistent from one JVM release to the next for the same code running on the same computer.
I think as long as you're talking about the "new" embedded systems (i.e. no or easy real-time or a general purpose computer in a smaller form-factor) then OS's like Windows CE or Linux will be OK.
For traditional embedded systems (i.e extremely limited resources or true real-time software) these OS's will come up short. They are too bloated for low resources systems and their timing is to variable for serious real-time work.
Of course, most of today's microprocessors aren't appropriate for hard real-time software either. Once you add complicated prefetch schemes and caches to the mix, you can't really do anything that requires fine timing precision.
Fortunately for traditional OS's, real-time software is a dying art and most real-time work is done in specialized hardware rather than software these days. In addition, the resource issue is not really much of a problem these days.
"Let programers do what they want. "
"thats great, assuming they all want to do it the same way."
Why should they all do it the same way? The argument typically advanced by those promoting coding standards is that they make the code easier to understand. If a programmer is going to be scratching his head because he's unfamiliar with the naming convention, he's certainly not going to be able handle C/C++ pointers or Java generics.
In truth understandability is really just an excuse. The main motivation for coding standards are power and a compulsive need to produce order where none is required. In practice, a manager or the "alpha" programmer dictates the bulk of the standard that everyone else has to live with. It's very rare that the process is democratic.
"You mean like this camera?"
No, not at all.
"Holograms have not take over photographs"
The fact that holograms haven't taken over photographs has nothing to do with people's preferences for 2D over 3D. It's because of the expense, lack of true color and the fact that people can't stand still that long. If you could point and shoot a hologram with full color using normal exposure speeds and the camera was less than $500, they'd be selling faster than iPods.
Holograms also solve the focus issue since they reproduce the wavefront that came from the original scene.
"Better from a technological standpoint, yes, but logistically impossible ...
but I'm afraid HTTP/HTML/CSS/Javascript is far too ingrained for that. "
On the other hand, consider how ingrained desktop applications were prior to the WWW. History is littered with the remains of technologies that are "too ingrained" to be replaced.
Let's face it though. Javascript is hack to make a web-based document viewing technology into an interactive one. It would be far better to upgrade HTTP and HTML to natively support the functionality that all interactive web-apps need then to download the same boiler-plate javascript code trillions of times forever and ever.
"They really would prefer that they be the gateway to the web and that you pay $$$ to them to be able to get the content as well as selling their OS. AJAX makes windows less relevant because you can run apps on firefox on any platform."
Sure, AJAX technology detects if you're charging for your web app and shuts down immediately if you are.
Seriously, there's no relationship between the type of technology you use for your application and your ability to charge for it.
Those are nice advantages. The only problem with your argument is that AJAX isn't required for any of them.
I think we've already gone too far in our pursuit of portable code.
Look at Java threading. You have to use synchronization to protect your thread against being preempted, while yielding to protect all the other threads in case you never are.
That's because the underlying process and thread models used by different OS can't be abstracted away in single model. So you end up with very little thread behavior that you can count on.
Cross-platform code will always be more complex and less satisfying than targeting a particular platform.
My interpretation is that the quality and usefulness of universally portable code will make all its users feel like someone is flipping them off.
"They are perfectly fine analogies. If there's a flaw, why don't you point it out instead of dismissing them off hand as "straw"?"
Sure. First of all we are talking about a decade of financial transactions over the Internet (at the most). Not 50 years, not hundreds of years, but only 10 years. In addition while connecting all the networks together provides some value, that value is not remotely comparable to the difference between doing calculations by hand vs. with a computer. There are also real-time use of computers that simply could not be done by hand at all. The difference between pre-Internet financial transaction capability and post-Internet financial transaction capablitity is negligable by comparison.
"Just as you made a "general observation" about how "young people" experience the world, I made one about old people, one which resonates well with how many old people react to new technology."
What you actually said "you're too old to realize just how much things have changed since you were young" which is not a comment on how old people react to new technology. But hey, don't let facts get in your way.
"You have presented absolutely zero evidence in favor of your position, only vague allusions to "it worked before" which are completely irrelevant, as several people have already pointed out."
So you don't think that "it worked before without it" is relevant to a discussion on the effects of removing something. Then what, pray tell, could possibly be relevant?
"ATMs, to take your examples, have been made unavailable because of script kiddie worms. What does that tell you?"
It tells me that the security of ATMs have been compromised by being connected to the Internet.
"But if you seriously think people wouldn't notice all that much if the Internet went down, you're seriously insane."
Keep those straw arguments coming.
"Insulting the parent poster implying that his stance is the result of youth puts you in a very poor light, especially since you're so obviously wrong"
..."
There was no insult involved, just the observation that it's difficult for those that haven't lived under different conditions to imagine what it was like. It was true for your parents, it's true for you, and it will be true for your children.
"Guns aren't necessary to the operation of national defense
"Computers aren't necessary to the operation of financial institutions"
Thanks for the straw arguments.
"I could write a thousand word post about the immense havoc that immediately would ensure if the Internet disappeared, but what's the use?"
Hey, if you don't want to write a thousand words, why bother writing any, right?
"you're too old to realize just how much things have changed since you were young"
What happened to your concern about insults? It's not an insult to suggest that someone who didn't live through a particular era might not understand it, it is an insult to suggest that someone who is older has been asleep for the last decade.
I suspect you're fairly young and have a great interest in technology. Thus the consequences seem more dire to you than to those who have lived longer under a pre-Internet society and have no special interest.
The Internet as we know it is not really necessary to the operation of financial institutions, education, and national defense. In fact one could argue that the Internet has made financial transactions more vunerable, and has been more of a distraction to students than a research tool.
Hey, they say the French love Jerry Lewis which I don't get, but they sure as hell were a lot smarter than the average US citizen when it came to WMDs in Iraq.
Hell, about 30% of Americans still believe that there are WMDs in Iraq, so I don't think we should be lecturing the French until we admit we were wrong.