Pfft, Barsoukov's stuff is sophmotic. Note, for instance, that he doesn't consider entrainment of the surrounding medium as a working mass in his "what it's not" section.
ion wind + air pulled along with it = lots of airflow
Don't believe me? Check out back issues of PopMech from the late 1960's, they build a fan with no moving parts out of lifter parts.
Townsend Brown worked on it in the late 20's to 40's and IIRC, but lived into the 1970's.
As far as I can tell even he realized it was ion wind at the end, because he wrote all about other such devices. He worked for years in the field, and the last device I can think of was an electric ash tray thay sucked in the smoke with a little fan and then collected it with an ionizer.
It was only after his death, more specifically the publication of Charles Berlitz's books, that he suddenly became the touchstone to the anti-gravity folks.
>causes a *temperature* change in the frozen particles
That does not provide propulsion, only the ability to leave the nucleus. The _dust_tail_ of a comet is still generally accepted to be due to radiation pressure.
> Anyhow, there's been no tests showing that a solar sail *could* work
Type "laser levitation" into Google. You'll get just under 10,000 hits, the first few pages of which are almost all examples of real-world experiments. People are doing this as I write this.
Your statement above is ill-informed. Then again, apparently Gold is too, because he makes direct claims that this everyday practical system does not exist, even though he could just as easily find this:
http://astp.msfc.nasa.gov/ast/presentations/3g_k no w.pdf...as I could in 30 seconds.
More to the point, if you type in "radiation pressure" you'll get an equally useful list of examples of space-related examples. The very first hit:
http://www.terrapub.co.jp/journals/EPS/pdf/5109/ 51 090979.pdf... contains a detailed study of the radiation pressure effects on a satellite going to the moon -- even though the effect is very small, it is required in this case to accurately calculate the orbit.
Or you could read this short little blurb, which is quite useful:
http://yarchive.net/space/spacecraft/radiation_p re ssure.html
Solar sails are not heat engines. Period. Neither are electric motors, balls rolling down hills, springs, or lots of other things. All of these "other things" have effeciencies much higher than the ideal heat engine.
Consider: what is the temperature of the electricity after it comes out of a motor? Does that explain the power you're getting from it?
Heat engines are only one way of many to extract energy, one our culture has become dependant on because we can dig up fuel cheaply. It is not a particularily good one however, and our widespread use of heat engines is likely to change in the next 20 years or so.
For instance, take an existing car that gets, say 30mpg. Now take out the normal engine, and replace it with an electric motor, fuel cell, and a reformer that extracts the hydrogen from the gas. This will improve milage to about 40mpg, even though reformers are rather ineffecient. This is because the energy in the fuel can be still extracted with higher effeciency as electricity than as heat, notably in the motor which is close to 90%.
Gold's argument is just plain dumb. I can't imgine how anyone could seriously suggest it. I wonder if even he believes it. In fact, a radiometer DOES spin towards the black side in a high vacume, a fact he should be familiar with.
Re:silly question... what's a microkernel?
on
Realtime OS Jaluna
·
· Score: 2, Informative
The basic difference is that the kernel in a microkernel system is just that, micro. It includes functionality only for the concepts of tasks, the memory they use, the CPU time they get, and the messages they pass to each other.
This is rather different than, say, Linux. Here the kernel includes all sorts of things, like networking stacks, device drivers, file systems, etc. These are basic parts of the kernel itself, along with everything in the microkernel too.
So how does one use a microkernel if it doesn't have all this (required) stuff? Basically all of these things are compiled into modules known as "servers", and run as separate tasks -- just like any other program. So if your web browser needs to send a request to a web server, it does so by (essentially) saying "hey microkernel, could you tell the networking program to send this to this address? Thanks!". In a traditional kernel your web browser would do a local "method call".
This might sound piquane, and for the end user it often is. However, in theory at least, microkernels offer the ability to help development. That's because you can load up or ditch any of these little "servers" without any effect on anyone else -- that's why they're so useful for RTOSs, because you can ditch what you don't need -- and even do so while the computer continues working. No reboots to fix a bug in your ethernet card driver...
I've been wondering this for some time now. I remember using QNX (back when it was QnX from Quantum!) on the ICON computers round-about 84-85. These were 268's with big screens, graphics, everything. The thing I remember most was that they were FAST, snappy, you know, everything this 2k box isn't.
So is there any downside to an RTOS? I know about the slots and scheduling yadda yadda, but these strike me as theoretical problems and not nessesarily real-world ones.
Can someone clue me in here? Why don't we all use QNX for everything?
I really like CVS actually. I have few complaints - which is odd for me. In four years of constant use, I'd like to see things change primarily in the GUI's I use with it. I'd like...
1) FAST way of knowing what I've changed, globally. Using WinCVS is SLOW for this task.
2) No CVS folders in my local source. I don't know how you avoid this though. However when I move source from one machine to another, it breaks CVS. That is a Bad Thing.
3) A better/easier way of sending my revisions into an existing tree on a global basis. You can do this fairly easily in the CLI but it's invisible as to what you're doing. Something like a two-stage commit would be excellent for this, you ask it to do the merge and it responds with a list of the files and a few lines of diff before going on.
Anyone here old enough to remember that series of "futuristic computer" videos that Apple did in the late 80's? This thing looks just like it.
Maury
This is not news. Doesn't ANYONE study history
on
.NETly News
·
· Score: 4, Insightful
Once again I find myself ashamed to be a part of an industry that can't remember anything five years into the past..NET has been done before, many times. The only news here is the hype, as always.
Let's see, unified runtime, libraries of code with multiple versions, simplified networked object support, standardized metadata...
OpenStep circa 1995.
Sure, OS used plists instead of XML (which didn't exist), a private system instead of UDDI (which didn't exist) and was aimed at C people instead of Java (whichy didn't exist) but the broad strokes are the same:
A multi-platform runtime with standardized libraries, which can exist as multiple versions (with resources) at the same time, with objects that can write themselves out so they can be manipulated as flat data (for storage or network invocation).
The differences are interesting too,.net includes more security features (useful in some contexts) and is multi-language instead of multi-platform. This last issue is a practical one only, at least until Mono is working. And they decided to go multi-language via an IDL, which I consider to be moronic (OpenStep used fat binaries, faster, smaller, better, realistic).
I'm sure other "old timers" will have their own similar systems to include for comparison, but the real point is not that OpenStep did it, but that SOMEONE did it.
And years later no one is using OS (mostly), whereas I'm sure five years from now.net will be one of the most used systems out there. That's the power of marketting. Look how well it worked on the droid on Salon.
The original note notes "Lots of people hated him. I believe he has been one of the truly great leaders of our time. He has completely turned NASA around during his 10 year tenure."
Ten years ago it was coming off the Challenger disaster and attempting to get funding for the space station. Morale sucked, and all the good science projects kept getting canned.
Today NASA has largely forgotten the Challenger disaster, to the point where it cut the space lifeboat. They continue to attempt to get funding for the hole-in-space station, but now they can't even justify why. Morale sucks, and all the good science projects keep getting canned.
Some change, indeed.
I don't know if Goldin is a good or bad guy, I don't think that's the point. The point is that he is definitely the WRONG guy. I don't know, making money at TRW during Star Wars doesn't really strike me as credentials for running NASA.
He did no good for NASA's image, and his hissy fit over Tito make him look like an ass. Congress doesn't seem to like him either. And he just can't seem to say no.
What NASA needs is Steve Jobs. A completely crazy git who will cancel a whole bunch of really great things and freak the crap out of everyone, but in the end leave a core with a vision and the bottom line to do it. You might not like the vision and be pissed off that he killed the Comet Smasher Express, but it would have died anyway, death of a thousand cuts.
I remember back in my Air Warrior days that the new version was always just two weeks away. After a while it became a running joke about anything at all, new machines, your new baby, etc.
Open on my desk is a copy of "Project Sherwood - The U.S. Program in Controlled Fusion", published in 1958 - I believe as a part of a huge nuclear energy conference in Geneva. I'll quote something from the conclusion for you:
"With ingenuity, hard work, and a sprinkling of good luck, it even seems reasonable to hope that a full-scale power-producing thermonuclear device may be built within the next decade or two."
Well _I_ find it amusing!
I believe it is safe to say we will not see fusion plants as power sources within our lifetime. Oh, it's certainly possible that we will build a working reactor, but no one will buy it. Why bother? We already have nukes and they're about the same cost to run. Better yet, coal is cheap.
We just don't need them. At least not right now. If we need more non-poluting power, we will build more nukes. We haven't even come close to saturating that market even for the existing overbuilt infrastructure. Now we have to build new devices and infrastructure for this new power source that we don't even need?
Sorry. Maybe as a space driver around 2100, but with micro-nukes that seems unlikey too.
Some basic points here...
1) Spacewar! was the first _computer_video_game. There were video games that were earlier (Tennis for Two and possibly a Golf game from England). There were computer games that were earlier (tic-tac-toe and such). Spacewar! was certainly the first to put them together.
2) The first video arcade game, as such, was neither Computer Space or PONG. It was Galaxy Game. It was built to the tune of one machine, but ran for seven years straight. It claims the title by about one month.
3) Computer Space was the first arcade game to make it out to the public, and thus arguably claims the title for itself. Also the dates are so close one may be able to show this was earlier than GG, but that might be tough.
Full details: www.gamesoffame.com
Maury
Slashdot Mirror
Pfft, Barsoukov's stuff is sophmotic. Note, for instance, that he doesn't consider entrainment of the surrounding medium as a working mass in his "what it's not" section.
ion wind + air pulled along with it = lots of airflow
Don't believe me? Check out back issues of PopMech from the late 1960's, they build a fan with no moving parts out of lifter parts.
Townsend Brown worked on it in the late 20's to 40's and IIRC, but lived into the 1970's.
As far as I can tell even he realized it was ion wind at the end, because he wrote all about other such devices. He worked for years in the field, and the last device I can think of was an electric ash tray thay sucked in the smoke with a little fan and then collected it with an ionizer.
It was only after his death, more specifically the publication of Charles Berlitz's books, that he suddenly became the touchstone to the anti-gravity folks.
>causes a *temperature* change in the frozen particles
k no w.pdf ...as I could in 30 seconds.
/ 51 090979.pdf ... contains a detailed study of the radiation pressure effects on a satellite going to the moon -- even though the effect is very small, it is required in this case to accurately calculate the orbit.
p re ssure.html
That does not provide propulsion, only the ability to leave the nucleus. The _dust_tail_ of a comet is still generally accepted to be due to radiation pressure.
> Anyhow, there's been no tests showing that a solar sail *could* work
Type "laser levitation" into Google. You'll get just under 10,000 hits, the first few pages of which are almost all examples of real-world experiments. People are doing this as I write this.
Your statement above is ill-informed. Then again, apparently Gold is too, because he makes direct claims that this everyday practical system does not exist, even though he could just as easily find this:
http://astp.msfc.nasa.gov/ast/presentations/3g_
More to the point, if you type in "radiation pressure" you'll get an equally useful list of examples of space-related examples. The very first hit:
http://www.terrapub.co.jp/journals/EPS/pdf/5109
Or you could read this short little blurb, which is quite useful:
http://yarchive.net/space/spacecraft/radiation_
Solar sails are not heat engines. Period. Neither are electric motors, balls rolling down hills, springs, or lots of other things. All of these "other things" have effeciencies much higher than the ideal heat engine.
Consider: what is the temperature of the electricity after it comes out of a motor? Does that explain the power you're getting from it?
Heat engines are only one way of many to extract energy, one our culture has become dependant on because we can dig up fuel cheaply. It is not a particularily good one however, and our widespread use of heat engines is likely to change in the next 20 years or so.
For instance, take an existing car that gets, say 30mpg. Now take out the normal engine, and replace it with an electric motor, fuel cell, and a reformer that extracts the hydrogen from the gas. This will improve milage to about 40mpg, even though reformers are rather ineffecient. This is because the energy in the fuel can be still extracted with higher effeciency as electricity than as heat, notably in the motor which is close to 90%.
Gold's argument is just plain dumb. I can't imgine how anyone could seriously suggest it. I wonder if even he believes it. In fact, a radiometer DOES spin towards the black side in a high vacume, a fact he should be familiar with.
It's ALWAYS the metric system:
http://www.wikipedia.org/wiki/Gimli_Glider
The basic difference is that the kernel in a microkernel system is just that, micro. It includes functionality only for the concepts of tasks, the memory they use, the CPU time they get, and the messages they pass to each other.
This is rather different than, say, Linux. Here the kernel includes all sorts of things, like networking stacks, device drivers, file systems, etc. These are basic parts of the kernel itself, along with everything in the microkernel too.
So how does one use a microkernel if it doesn't have all this (required) stuff? Basically all of these things are compiled into modules known as "servers", and run as separate tasks -- just like any other program. So if your web browser needs to send a request to a web server, it does so by (essentially) saying "hey microkernel, could you tell the networking program to send this to this address? Thanks!". In a traditional kernel your web browser would do a local "method call".
This might sound piquane, and for the end user it often is. However, in theory at least, microkernels offer the ability to help development. That's because you can load up or ditch any of these little "servers" without any effect on anyone else -- that's why they're so useful for RTOSs, because you can ditch what you don't need -- and even do so while the computer continues working. No reboots to fix a bug in your ethernet card driver...
I've been wondering this for some time now. I remember using QNX (back when it was QnX from Quantum!) on the ICON computers round-about 84-85. These were 268's with big screens, graphics, everything. The thing I remember most was that they were FAST, snappy, you know, everything this 2k box isn't.
So is there any downside to an RTOS? I know about the slots and scheduling yadda yadda, but these strike me as theoretical problems and not nessesarily real-world ones.
Can someone clue me in here? Why don't we all use QNX for everything?
Anyone care to read/review/comment/review:
http://www.wikipedia.org/wiki/INMOS_Transputer
BTW turgid, the nCube was not Transputer based, they used their own custom CPU.
I really like CVS actually. I have few complaints - which is odd for me. In four years of constant use, I'd like to see things change primarily in the GUI's I use with it. I'd like...
1) FAST way of knowing what I've changed, globally. Using WinCVS is SLOW for this task.
2) No CVS folders in my local source. I don't know how you avoid this though. However when I move source from one machine to another, it breaks CVS. That is a Bad Thing.
3) A better/easier way of sending my revisions into an existing tree on a global basis. You can do this fairly easily in the CLI but it's invisible as to what you're doing. Something like a two-stage commit would be excellent for this, you ask it to do the merge and it responds with a list of the files and a few lines of diff before going on.
The Concorde seats 100. This one seats 300. Expect the price per seat to fall by 3x for that reason alone.
Now add the fact that there actually is a market for long-haul 300 seat aircraft, so it's quite possible they'll sell more than 20.
Finally, consider that the price of R&D has fallen dramatically with the increasing speed of computers.
It all adds up. It might be business-class price, but it won't be Concorde-class price.
Anyone here old enough to remember that series of "futuristic computer" videos that Apple did in the late 80's? This thing looks just like it.
Maury
Once again I find myself ashamed to be a part of an industry that can't remember anything five years into the past. .NET has been done before, many times. The only news here is the hype, as always.
.net includes more security features (useful in some contexts) and is multi-language instead of multi-platform. This last issue is a practical one only, at least until Mono is working. And they decided to go multi-language via an IDL, which I consider to be moronic (OpenStep used fat binaries, faster, smaller, better, realistic).
.net will be one of the most used systems out there. That's the power of marketting. Look how well it worked on the droid on Salon.
Let's see, unified runtime, libraries of code with multiple versions, simplified networked object support, standardized metadata...
OpenStep circa 1995.
Sure, OS used plists instead of XML (which didn't exist), a private system instead of UDDI (which didn't exist) and was aimed at C people instead of Java (whichy didn't exist) but the broad strokes are the same:
A multi-platform runtime with standardized libraries, which can exist as multiple versions (with resources) at the same time, with objects that can write themselves out so they can be manipulated as flat data (for storage or network invocation).
The differences are interesting too,
I'm sure other "old timers" will have their own similar systems to include for comparison, but the real point is not that OpenStep did it, but that SOMEONE did it.
And years later no one is using OS (mostly), whereas I'm sure five years from now
Maury
The original note notes "Lots of people hated him. I believe he has been one of the truly great leaders of our time. He has completely turned NASA around during his 10 year tenure."
Ten years ago it was coming off the Challenger disaster and attempting to get funding for the space station. Morale sucked, and all the good science projects kept getting canned.
Today NASA has largely forgotten the Challenger disaster, to the point where it cut the space lifeboat. They continue to attempt to get funding for the hole-in-space station, but now they can't even justify why. Morale sucks, and all the good science projects keep getting canned.
Some change, indeed.
I don't know if Goldin is a good or bad guy, I don't think that's the point. The point is that he is definitely the WRONG guy. I don't know, making money at TRW during Star Wars doesn't really strike me as credentials for running NASA.
He did no good for NASA's image, and his hissy fit over Tito make him look like an ass. Congress doesn't seem to like him either. And he just can't seem to say no.
What NASA needs is Steve Jobs. A completely crazy git who will cancel a whole bunch of really great things and freak the crap out of everyone, but in the end leave a core with a vision and the bottom line to do it. You might not like the vision and be pissed off that he killed the Comet Smasher Express, but it would have died anyway, death of a thousand cuts.
Maury
I remember back in my Air Warrior days that the new version was always just two weeks away. After a while it became a running joke about anything at all, new machines, your new baby, etc.
Open on my desk is a copy of "Project Sherwood - The U.S. Program in Controlled Fusion", published in 1958 - I believe as a part of a huge nuclear energy conference in Geneva. I'll quote something from the conclusion for you:
"With ingenuity, hard work, and a sprinkling of good luck, it even seems reasonable to hope that a full-scale power-producing thermonuclear device may be built within the next decade or two."
Well _I_ find it amusing!
I believe it is safe to say we will not see fusion plants as power sources within our lifetime. Oh, it's certainly possible that we will build a working reactor, but no one will buy it. Why bother? We already have nukes and they're about the same cost to run. Better yet, coal is cheap.
We just don't need them. At least not right now. If we need more non-poluting power, we will build more nukes. We haven't even come close to saturating that market even for the existing overbuilt infrastructure. Now we have to build new devices and infrastructure for this new power source that we don't even need?
Sorry. Maybe as a space driver around 2100, but with micro-nukes that seems unlikey too.
Maury
Consider this comment:
After an intensive hands-on Linux project lasting several months, I was able to provide my client with a pertinent answer to this question.
Which is followed by this comment:
The primary reason for this decision was a $10,000 saving on his IT budget!
Facinating.
Galaxy Game indeed took coins, although dimes, not quarters. The machine was built on the PDP-11, not the IBM 704. Maury
Some basic points here... 1) Spacewar! was the first _computer_video_game. There were video games that were earlier (Tennis for Two and possibly a Golf game from England). There were computer games that were earlier (tic-tac-toe and such). Spacewar! was certainly the first to put them together. 2) The first video arcade game, as such, was neither Computer Space or PONG. It was Galaxy Game. It was built to the tune of one machine, but ran for seven years straight. It claims the title by about one month. 3) Computer Space was the first arcade game to make it out to the public, and thus arguably claims the title for itself. Also the dates are so close one may be able to show this was earlier than GG, but that might be tough. Full details: www.gamesoffame.com Maury
> like come on computers shouldnt be appliances.
Like, come on, they ARE appliances.
What rock do you live under?
Maury