The problem is that compared to a pared down monolithic kernel, the savings aren't that good. If at all. NB: I'm making things up as a go along, so add salt to taste, and don't hesitate to flame and correct:
I think Mach needs something like 4 meg of runtime memory to manage IPC (?). 'Thing is that since it is completely dynamic, each kernel metacomponent (like a filesystem driver) needs to have a very generic interface. These add up. Then you need to configure the various objects at boot time and store that in ram. A statically compiled kernel can use standard compiler tricks like dead code elimination (especially if you are allowed to make the whole program assumption) to axe out huge swaths of unneeded code.
The real value of microkernels is stability. You can use a buggy driver, if you need to. On a production system. The driver can crash without killing the kernel. Just add a heartbeat monitor and you get life-support for buggy drivers. The boon for developers of said drivers is obvious.
Now is where I start speculating: I'd like to see a pyKernel. Write low level performance critical parts of the code in C, but write the rest of the kernel in python. An example: the code that performs context switch is obviously in C, but the code that implements the policy is in python.
I know there's a LISPos project, but IIRC it got stalled early on in bickering and overreaching (If you run code from a safe language, you can get rid of expensive process separation and run them all in one memory space). Any other projects out there?
It's been a long time since I saw the ellipsis used in place of the period, comma, or semicolon. After all, most people stop doing that a few weeks into their email experience.
But "birds" provide wider coverage -- larger footprint from higher altitude, so you'd need ALOT of these wings. Still might be cheap enough for local coverage, but likely not global.
What about sterling engined gliders? Basically, they have GPS and simple station holding avionics, so they circle in the same general area, day after day. They're above the clouds, so they can recharge the fuel cells for the night's flight during the day. During the day, they take advantage of the heat differential between black top of wing and white bottom for a sterling engine.
huh? has anyone built one? How high could you get it to go?
I am always appalled at the details of what should be a fine legal system (I mean, the premises on which it is built make sense).
However, the fact that state does not have any liability for seized goods, nor a burden of proof to seize it in the first place is completely flabergasting. I just don't see how this travesty came about?
It seems to me that the state should have to bond all items it seizes. If they are kept more than so long, a partial payment (rent) is made to the owner, and upon their return, any value diminishment is to be reimbursed from the bond. Thus, if a car is damaged in the pound, the bond will repair it, or if a computer is obsolesed, the owner reimbursed.
This will give the agencies the incentive to a) care for physical evidence, and b) return it in a timely manner -- for example, returning a computer after having made a certified copy of the hard drive (or keeping the hard drive and offering the owner a chance to make a copy).
yes. I was unimpressed with Inversions by the same token that I was unimpressed with Greg Bear's last eon novel; the one where Olmy is trapped in a planet waiting for rescue.
It's the old Star Trek bait and switch tactic; hook the SciFi audience with a few technology references, then write a completly non SciFi story. Any Star Trek that occurs while Kirk is unable to contact the ship, or any story taking place on the HoloDeck all use this. Inversions and the Greg Bear novels both do this, although the former less blatantly (in that you only realise it is a culture-universe novel if you are familiar with the concept before).
First person!?! Argh! I hate fscking first person. Only one in 10 novels brings it off. It's almost as bad as writing dialecally (which I recall Mr. Banks has also commited, in Feersum Enjinn).
Conscider Phelebas, not Player of Games, but that's only 'cause you kinda asked.
I was going to bring up those books by -- now I forget -- Michael Moorecock or Brian Aldiss. Something about Riders of the Apocalypse? I read them only once, a long time ago, and I kept getting confused as to chronology. People kept on popping in and out of the story. Ring any bells?
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State Of The Art is great, if not as detailed as the others. I also enjoyed the non-culture POV of Conscider Phelebas; perhaps that is why I liked SOTA -- it is narrated by the 1.0 drone Unhana Closp (sp?).
I liked feersum endjinn but not enough to reread it, and it's been a goodly number of years.
This patenting of specific functions smacks of Microsoft tactics
I'm suprised. Really. I had long understood that the industry had agreed that specifications are not patentable. Implementations, yes, but not specs. This is why it is legal to create plug-in replacements for things like windows, libc, whatever; because their APIs are unprotectable. Of course, you are under no obligation to publish any or all (c.f. intel undocumented instructions) of these APIs.
Surely the instructionset of a CPU is its API? Now if intel were patenting nifty tricks to implement these instructions, all would be well, but I just don't see how anyone could think it possible to patent an API (MIPS case nonwithstanding -- key here is the subclaim "and method for same", I think).
So I'll throw this out for discussion: what nifty implementation tricks do you see as patentable?
Negative example: the tomasulo algorithm, which is a big ball of hair implementationwise but effectively just renaming.
Positive example: outof order commit with exception coherence.
yup. Since the original host (infection 0?) was infected via an email attachment, it would have been easy for the attackers to tunnel through the firewall (port 80, perhaps: outgoing information encoded in the URLs).
Greenspun's Tenth Rule of Programming states that "any sufficiently complicated C or Fortran program contains an ad hoc informally-specified bug-ridden slow implementation of half of Common Lisp"
DivX does partial decoding instead of dropping frames? Pretty nifty. And a P500III isn't fast enough to have buchloads of cycles left over? That is scary
I think you can basically apply the diagonalisation argument to show that it is impossible for code that is able to scan itself to be translated correctly 100% of the time.
Ta. That's exactly the sort of overview I was after. So the key for the cipher changes over time. Doesn't this approach give you known plaintext, tho (you can guestimate what the counter is). Why not encrypt the previous value, or the low order digits of the time?
If the pressure in the suit is lower than the outside pressure, the main problem would be the methane leaking in. Not that I know whether this is the case, but let's speculate.
Since methane stinks, you'd probably notice the leak pretty quickly, and be able to hold your breath until the leak was fixed. Since methane isn't poisonous for us, we might only keep the helmet oxygenated and fill the rest of the suit with warmed up methane. The smaller the area you need to protect against leaks, the easier, and the helmet has the excellent property of not having any moving parts.
The importance of a good random number generator is often overlooked. Since symmetric (== fast)session keys are mostly randomly generated (and then encrypted by the asymmetric (==dog slow) user keys) if the the random number generator is weak, this can undermine the whole system's security.
You all recall that netscape's already paltry 40 bit encraption actually only had something like 14 bits of entropy, because so many bits came from the easily guessable clock (or something like that).
Anyway, Yarrow is from the always popular counterpane people. I haven't had a look at it myself yet, so if anyone has given it a gander, a summary would be well appreciated.
Reminds me of a short story by Jorge Borges' "Library of Babel" which was a near-infinite structure that contained a staggering number of identical books. In fact, every single possible book of that lenght was in the library.
Some books were all "a" repeated over and over, some were the true histories of famous people, some were the false histories of poor people. Some books coninued on from other books... you get the idea.
The book that was the "holy grail" is the book that indexes all the other true books (probably with several continuing tomes). Of course, there were a large number of false indexes lying around.
The story is basically making exactly your point, in that the difference between information and data is selection. I can enumerate all numbers encoding 3 minute songs at cd quality, but only a small fraction of them will be interesting to listen to. The information is telling you which one data point is interesting to listen to.
To continue this rambling post some more; in the vein of GEB, any creation can be facted, by stating that it is a creation.
"cherry blossoms fall pink / with dew drops / heavy from morning light" is my creation, and thus can be copyrighted.
However, the entire previous sentence is a fact, and thus cannot (nor can this one). Tim Robbins ref: this sentence is in the mob; it has italic connections. This sentence is pregnant, it is missing its period
I believe this was a constructive proof; they not only proved it was possible, but also how to solve for motions. The problem's open status suggests that no such solution was known earlier.
You don't have to guarantee that you can rollback a file; just being smart about not overwriting previous versions until you have to (and then in a LIFO/LRU order) should be a neato 90% solution.
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The problem is that compared to a pared down monolithic kernel, the savings aren't that good. If at all. NB: I'm making things up as a go along, so add salt to taste, and don't hesitate to flame and correct:
I think Mach needs something like 4 meg of runtime memory to manage IPC (?). 'Thing is that since it is completely dynamic, each kernel metacomponent (like a filesystem driver) needs to have a very generic interface. These add up. Then you need to configure the various objects at boot time and store that in ram. A statically compiled kernel can use standard compiler tricks like dead code elimination (especially if you are allowed to make the whole program assumption) to axe out huge swaths of unneeded code.
The real value of microkernels is stability. You can use a buggy driver, if you need to. On a production system. The driver can crash without killing the kernel. Just add a heartbeat monitor and you get life-support for buggy drivers. The boon for developers of said drivers is obvious.
Now is where I start speculating: I'd like to see a pyKernel. Write low level performance critical parts of the code in C, but write the rest of the kernel in python. An example: the code that performs context switch is obviously in C, but the code that implements the policy is in python.
I know there's a LISPos project, but IIRC it got stalled early on in bickering and overreaching (If you run code from a safe language, you can get rid of expensive process separation and run them all in one memory space). Any other projects out there?
It's been a long time since I saw the ellipsis used in place of the period, comma, or semicolon. After all, most people stop doing that a few weeks into their email experience.
Thanks for the flashback!
But "birds" provide wider coverage -- larger footprint from higher altitude, so you'd need ALOT of these wings. Still might be cheap enough for local coverage, but likely not global.
How self similar are the air streams at altitude? How far do I have to fly in order to find one to "blow me back" to where I was?
What about sterling engined gliders? Basically, they have GPS and simple station holding avionics, so they circle in the same general area, day after day. They're above the clouds, so they can recharge the fuel cells for the night's flight during the day. During the day, they take advantage of the heat differential between black top of wing and white bottom for a sterling engine.
huh? has anyone built one? How high could you get it to go?
Wouldn't the computer case work like a faraday cage and sheild the hard-drive?
I am always appalled at the details of what should be a fine legal system (I mean, the premises on which it is built make sense).
However, the fact that state does not have any liability for seized goods, nor a burden of proof to seize it in the first place is completely flabergasting. I just don't see how this travesty came about?
It seems to me that the state should have to bond all items it seizes. If they are kept more than so long, a partial payment (rent) is made to the owner, and upon their return, any value diminishment is to be reimbursed from the bond. Thus, if a car is damaged in the pound, the bond will repair it, or if a computer is obsolesed, the owner reimbursed.
This will give the agencies the incentive to a) care for physical evidence, and b) return it in a timely manner -- for example, returning a computer after having made a certified copy of the hard drive (or keeping the hard drive and offering the owner a chance to make a copy).
yes. I was unimpressed with Inversions by the same token that I was unimpressed with Greg Bear's last eon novel; the one where Olmy is trapped in a planet waiting for rescue.
It's the old Star Trek bait and switch tactic; hook the SciFi audience with a few technology references, then write a completly non SciFi story. Any Star Trek that occurs while Kirk is unable to contact the ship, or any story taking place on the HoloDeck all use this. Inversions and the Greg Bear novels both do this, although the former less blatantly (in that you only realise it is a culture-universe novel if you are familiar with the concept before).
First person!?! Argh! I hate fscking first person. Only one in 10 novels brings it off. It's almost as bad as writing dialecally (which I recall Mr. Banks has also commited, in Feersum Enjinn).
Conscider Phelebas, not Player of Games, but that's only 'cause you kinda asked.
I was going to bring up those books by -- now I forget -- Michael Moorecock or Brian Aldiss. Something about Riders of the Apocalypse? I read them only once, a long time ago, and I kept getting confused as to chronology. People kept on popping in and out of the story. Ring any bells?
State Of The Art is great, if not as detailed as the others. I also enjoyed the non-culture POV of Conscider Phelebas; perhaps that is why I liked SOTA -- it is narrated by the 1.0 drone Unhana Closp (sp?).
I liked feersum endjinn but not enough to reread it, and it's been a goodly number of years.
This patenting of specific functions smacks of Microsoft tactics
I'm suprised. Really. I had long understood that the industry had agreed that specifications are not patentable. Implementations, yes, but not specs. This is why it is legal to create plug-in replacements for things like windows, libc, whatever; because their APIs are unprotectable. Of course, you are under no obligation to publish any or all (c.f. intel undocumented instructions) of these APIs.
Surely the instructionset of a CPU is its API? Now if intel were patenting nifty tricks to implement these instructions, all would be well, but I just don't see how anyone could think it possible to patent an API (MIPS case nonwithstanding -- key here is the subclaim "and method for same", I think).
So I'll throw this out for discussion: what nifty implementation tricks do you see as patentable?
Negative example: the tomasulo algorithm, which is a big ball of hair implementationwise but effectively just renaming.
Positive example: outof order commit with exception coherence.
yup. Since the original host (infection 0?) was infected via an email attachment, it would have been easy for the attackers to tunnel through the firewall (port 80, perhaps: outgoing information encoded in the URLs).
Cute typo:
"in lisp in C++"
Greenspun's Tenth Rule of Programming states that "any sufficiently complicated C or Fortran program contains an ad hoc informally-specified bug-ridden slow implementation of half of Common Lisp"
DivX does partial decoding instead of dropping frames? Pretty nifty. And a P500III isn't fast enough to have buchloads of cycles left over? That is scary
I think you can basically apply the diagonalisation argument to show that it is impossible for code that is able to scan itself to be translated correctly 100% of the time.
Tho I'm not completely sure.
Cryptonomicon: They all had laptops with cameras. If the user left the view of the camera, the password had to be reentered.
Ta. That's exactly the sort of overview I was after. So the key for the cipher changes over time. Doesn't this approach give you known plaintext, tho (you can guestimate what the counter is). Why not encrypt the previous value, or the low order digits of the time?
Johan
If the pressure in the suit is lower than the outside pressure, the main problem would be the methane leaking in. Not that I know whether this is the case, but let's speculate.
Since methane stinks, you'd probably notice the leak pretty quickly, and be able to hold your breath until the leak was fixed. Since methane isn't poisonous for us, we might only keep the helmet oxygenated and fill the rest of the suit with warmed up methane. The smaller the area you need to protect against leaks, the easier, and the helmet has the excellent property of not having any moving parts.
The importance of a good random number generator is often overlooked. Since symmetric (== fast)session keys are mostly randomly generated (and then encrypted by the asymmetric (==dog slow) user keys) if the the random number generator is weak, this can undermine the whole system's security.
You all recall that netscape's already paltry 40 bit encraption actually only had something like 14 bits of entropy, because so many bits came from the easily guessable clock (or something like that).
Anyway, Yarrow is from the always popular counterpane people. I haven't had a look at it myself yet, so if anyone has given it a gander, a summary would be well appreciated.
Reminds me of a short story by Jorge Borges' "Library of Babel" which was a near-infinite structure that contained a staggering number of identical books. In fact, every single possible book of that lenght was in the library.
Some books were all "a" repeated over and over, some were the true histories of famous people, some were the false histories of poor people. Some books coninued on from other books... you get the idea.
The book that was the "holy grail" is the book that indexes all the other true books (probably with several continuing tomes). Of course, there were a large number of false indexes lying around.
The story is basically making exactly your point, in that the difference between information and data is selection. I can enumerate all numbers encoding 3 minute songs at cd quality, but only a small fraction of them will be interesting to listen to. The information is telling you which one data point is interesting to listen to.
To continue this rambling post some more; in the vein of GEB, any creation can be facted, by stating that it is a creation.
"cherry blossoms fall pink / with dew drops / heavy from morning light" is my creation, and thus can be copyrighted.
However, the entire previous sentence is a fact, and thus cannot (nor can this one). Tim Robbins ref: this sentence is in the mob; it has italic connections. This sentence is pregnant, it is missing its period
erm. I forgot my point. ramble ramble
I believe this was a constructive proof; they not only proved it was possible, but also how to solve for motions. The problem's open status suggests that no such solution was known earlier.
Phutureboy was at least funny. You're just stodgy and misunderstanding on purpose. Bah!
and that has what to do with communism?
You don't have to guarantee that you can rollback a file; just being smart about not overwriting previous versions until you have to (and then in a LIFO/LRU order) should be a neato 90% solution.