I can't help but wonder if you managed to get through college without giving out your SSN. Where I went (U of Texas), practically everything required your SSN. Regisitration, Test, Homework Papers, Telephone Services, etc.
From my understanding of ITAR (the base set of regulations on munitions and cryptography products agreed to by most countries), it is always legal to import a product assuming the export is legal from the parent country (at least for cryptography products). This means if you can legally export something from the UK, then you can legally import it in the US. The problem here is that many products originate in the US and cannot be legally exported (except to Canada). So it is also illegal to import them elsewhere, because the export would have occured through illegal, though trival, means.
On a totally different subject, I found out yesterday that a "crypologist" is a person who studies unknown animals, like bigfoot, lochness, etc. From this I take it "crypt" is the latin root for the unkown, and graphy is the practices/art of something? So cryptography really means "the art of the unkown." Sound like a some kind of cult activity.:)
What site can you go to on the internet that is updated more than slashdot? None that I have seen
Try newslinx.com. They have more news than you can handle, updated much more frequently than slashdot.
Tax and Lawsuit protection
on
Red Hat Europe
·
· Score: 1
IIR, Intel has 40+ corportations just this reason. It's standard to create a new corp when opening a site up overseas. Each country has their own laws that could open you up to a lawsuit. By starting a new corp, you limit your liability to just the assests of that company. Also the taxes will be limited to that companies earning.
This is probably RedHat's primary motivation here, as they already sold in most countries already.
When I moved here last year, I looked at some apartments near Apple in Santa Clara. $3400 a month! Holy cow. It was less than 900sq ft. You can freakin buy a humongous mansion anywhere else for that kind of money. The funny thing is, I almost took the apartment.
I live in San Jose and a saw on the new a few weeks back that Santa Clara is now offering "low income housing loans" for people making under $100,000/year. As well, I recall that the richer part of Colorado Springs (or where the host ski spot is), also has low income housing loans for the poor saps making $100K.
What I want to know is, where is the *cheapest* place in the US to live including cost of a T1/cable modem? That's one thing you don't hear much in reports of housing out here. There are hundrededs (well probably not that many) of ISPs here and internet access is cheap because of the competition. Now, I don't think I could live anywhere that leaves me with a modem as my only option.
Uhh, what is a gamma channel? Gamma is traditionally associated with color calabration in computer graphics. However it is always applied as a single function over an entire image, meaning there is no need for a channel. Am I missing something?
My favorite disassembler is IDA. It handles a lot of other targets as well. Having said that, I'd like to point out this argument is flawed. It's not always possible to disassemble something and then reassemble it. Case in point I made a program that sort makes this task impossible with a traditional disassembler.
Even without using something like this, disassembly of programs cannot be 100% correct. There is a lot of information needed to reconstruct a program that is thrown away by the compiler. For example you can't determine where a jump table (switch statement) or function pointer (virtual function) will lead to without actually executing the program and then it's not possible to cover all of the cases that could occur. IDA does a pretty good job of guessing though. Also IDA has hacks if it is looking at C code like looking for procedure frame headers (push ebp; mov ebp, esp) and termination code (pop ebp; ret). My solution to correct disassembly is to use emulation. This insures you never have an incorrect interpretation, but you will miss code that is never executed, and this can be important for understanding how errors and exceptions are handled.
Just because you can dissemble something doesn't mean you can understand it. It requires a huge amount of time to try to comprehend uses for unnamed memory locations and layout of data structures. In the case of a driver this is frustrated by the fact you are dealing with a lot of hidden code and data (the logic on the hardware). Not all drivers are "small pieces of code." Having looked at several vendor's Direct3d driver source code I can tell you each was extremely large and complex. Writing the driver with full knowledge of everything is hard enough, but disassembling one and understanding it would require super human willpower. There are all sort of commands that will do different things depending on that state of the card, so you have to understand what previously executed code was important to getting the card into that state.
I wonder if domain names will ever replace trademarks? No need for lawyers, no complicated searches and forms to fill out. No accidental granting 2 people the same TM. Instantly internationally binding and automatically enforced. If you compared the convience domain names present over TMs, they are damn cheap.
The only thing that remains is an automatic image TM system for logos, etc. Perhaps you submit your logo in a vector format and it is compared using a yet to be invented standard algorithm to other registered images. If a match of X% probability occurs the image is rejected.
While I think they are heading in the right direction, it doesn't sound like they have gotten very far according to the article. Thus far they have only run a command-line program that uses very few system calls (the Borland compiler). Consider what is needed by a compiler:
Plus a half a dozen misc functions. They state in the article that they haven't even started on the GUI, perhaps the hardest part. You can't just clone a few bits kernel32.dll and winnt.dll and say you have a windows clone. They also make no mention of how they plan to implement DDK which, IMO, would be the whole point of making a windows clone. Without device drivers what good is an OS?
The WINE project is *way* beyond this. Also WINE benefits tremendously by having a linux core and thus a solid device driver base behind it. Having said that, there are 2 problems with Wine. The first will probably never be surmounted, and that it will never be able support hardware that has win32 only drivers, and many of the APIs Microsoft has developed don't exist under linux so even if someone was willing and able to port, they couldn't. Take Direct3d for example. The best you could hope is to make a D3D->GL layer inside WINE, but it's not a very good mapping. Then there are weirder things like : CryptoAPI, Telephony API, etc.. where there is nothing at all like it under linux.
The second problem with WINE is that it is a single process solution. It makes no attempts to emulate the entire system, just the current process. This means you can't : debug a process, drag and drop, and other forms of IPC that many programs depend on. I believe this can be fixed, but will require a fairly big change to WINE.
Another project to look at that is very interesting is the FX!32 system by DEC. This system actually runs under NT, so they didn't have to write APIs except to thunk from 64->32->64. But it can run native intel binaries with very little slow down by doing dynamic code translation.
(wow, I just noticed "Linux" is not the Microsoft Spell Checker)
Since we are on this topic, I'm trying to get people to test a program I made. This is Windows only right now, but it compresses a Win32 Executable and adds a stub program to it that decompresses the program in memory when it runs. This turns out to be a very tricky thing to do because of dll imports, resources, thread local storage, and so on. Anyway, if you have any programs that don't work with it, mail me...
sounds good for robots
on
uCsimm News
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· Score: 3
compared to other micro boards used for robotics:
pros - low power ussage when idle - lots of ram (for the size) - good number of io/ports. good for controlling servo motors and reading digital sensors. - fairly fast. Probably good enough to do some image processing. - ethernet useful for fast experimentation in tethered mode. - nice environment to work in (linux!)
cons - Needs at least one A/D converter. - Wireless Ethernet would be more useful. Autonomous robots aren't going to be able to use plain ethernet.
This is not what is going to happen, but with 128 bit addresses you could just pick a number at random and use it. The odds of 2 people chosing the same number is low enough to be acceptable.
The actual probability is approx:
1- exp(-n*n/m)
where n is the number of addresses selected and m is the total addresses available.
If 4 billion people select addresses at random then the odds of a collision are: 1 in 415,828,534,307,635,078.
To put this number in perspective, your odds of guessing the right number to a 56bit DES encryption key on your first try is 1 is much better: 1 in 72,057,594,037,927,936
We won't be running out of IP addresses anytime soon. 2^128 is not big enough that we could assign each atom on the planet is own IP address (this number is ~2^170), but we certainly could assign each atom that could possibly be seen it's own IP (i.e. by excluding those in the earth's core). Considering that you need a fair number of atoms to store just to store a 128bit number, I think we are safe until space travel explodes.
Thanks for the reiview for those of us not keeping up with the cpu wars.
Jonathan
Re:The real difference between Emacs and Word
on
RMS Responds
·
· Score: 1
Don't forget not everyone has English as a native language. Word is a fully internationized product. I find this very useful when writing emails in other languages. Who can remember all the tildes and accent marks? Spell as you go helps refresh your memory. Also since I have the no-can-spell birth defect, I find it help me a lot with english.
While it true that stories aren't stored on/., in many cases I never read the actual story. Besides the fact the site is probably slashdotted, I'm more interested in what people here have to say about a topic. Often you will get much more information here than is presented in the article, so it is a waste of time to read them.
People on/. exercise brevity and with moderation it's easy to read according to how much free time you have, unlike external articles that require good skimming skills to find useful information.
While the accuracy of information here is not as well researched, it usually doesn't need to be because it is written by engineers who know what they are talking about. Journalist generally aren't engineers.. consider the salary differences.
I see the stories simply as a focus point of conversation, and it is Rob who is picking the conversations, not the journalist. There are literally several hundred online articles published daily by major papers, most of them don't provide much new information.
"The United States launched its first comet mission in February -- the Stardust spacecraft, which is to pass within 140 km (90 miles) of the Comet Wild-2 in January 2004. The mission hopes to be the first to capture dust from a comet and return it to Earth in 2006. "
Ok this is off topic, but, can anyone confirm or deny that the Stardust Casino and Hotel is actually named after abomb fallout, because it was constructed during the period of time when atomic testing occured in Nevada? I have a long standing bet with a friend, and we can't nail this down. I read this a long time ago, but can't find it now. If you look at the stardust sign with all the lights, it looks like an abomb..
Hmm. I'm note sure about this, any IP lawyers around? First of all, of the stories about companies posted on/. are not all positive. In fact, many are negative are accompanied with what could be construed as liabacious (from AC posters). In these cases, it is probably the case the companies don't say anything because the don't want to cause further bad press, or they (their lawyers at least) are just not aware of/. IIR, in a recent case is was decided in playboys favor against people using the word playboy in META tags. In most cases the META tags are not seen by the end user, so there is no mistaking the site for the real company. However they were deriving a profit (through increased traffic) through the use of the mark. I see a parallel on/. I think it would be a good idea to put a "X is a trademark of X" somewhere on/. to cover your butt. Even if you are not making a profit, you can infringe on a trademark. I think there is a good reason why newspaper stories almost always attribute any tm they display.
I've been reading the comments and I am really surprised there isn't much backlash../ers are famous for shooting down anyone who becomes sucessful.
Anyway, congrats!
I've always wondered about one thing about./ There is use of trademarks on the front page (for example today we see SGI's logo). Often the trademark is not attributed to the owner of the mark. Now that another company is responsible for you legally, while you have to change some policies that could put them at legal risk, such as this and anonymous posters.
So what was the sales price (ballpark?) It'll come out soon enough...:)
Re:The real difference between Emacs and Word
on
RMS Responds
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· Score: 1
What are you saying? Spell as you go is my favorite feature of all time! Mainly because I cannot spell. And it is done very well, the editor doesn't "nag" you as you claim. It does jaggy underlines in red, which is easy to ignore if you don't care.
And unlike 'check everything at the end', spell as you go lets you improve your spelling skills at the time when you are thinking about it.
I still use emacs for programming... if it had spell as you go I would use it for text editing as well. Without wysiwyg and a graphical interface drafting a business letter with graphics would be extremely hard in emacs. Also let's not forget printing....
I don't know that Samba and Apache selected the forking model by choice. Not to long ago threads really didn't work under linux, so there was no choice. I had a similar experience while working on a video game called Golgotha. We *really* had to have threads, but they didn't exists or didn't work properly.
The kernel has had fundamental support for them for a longer period of time, but a reliable thread safe libc (and libX11) did not surface until recently (the last year or so). Even now the distributions are struggling to get everything converted over to the new glibc.
Even though linux now has good thread support, gdb has trouble with them (last time I checked, which was a while back). Also, apache and samba are not linux-only products. The safest and most portable approach to take back then was to use a forking model.
Other than taking up an too much memory and thus causing swapping, I don't see why a threaded model would be any faster than forking model if pooling is used. Pooling keeps a fixed number of processes running all the time and dispatches request to them. When they finish they sleep and wait for the next request. This way you have the safety of a separate process space and you avoid the forking (as in you "forking piece of sheet") over head. You let each pooled process have a fixed lifetime in order to clean up any leaked memory. Some systems have libc leaks that can't be avoided, so this is important to long-term stability.
You might argue that a thread context switch is less expensive than a process context switch. Under NT (and 95), all threads are scheduled without regard to what process they belong to, so at most could skip some page table changes when going from one thread to the next. I doubt that is the case, because threads jump from ring3 to ring0 and back while executing system functions (ensuring they have different page tables). Also threads have a separate segment mapping for fs. A 3->0->3 context switch is accomplished by an interrupt in NT. One way to speed things up in linux might be to have a way to pool system request up in ring3 and then dispatch them all at once in ring0. NT did this with their GDI code. Doing this for all system calls wouldn't require a huge change in the kernel, but it would make user code harder to write as system calls have to be parallelized. GDI doesn't require any changes to user level code, because there are no return codes to worry about for graphic drawling operations. Xlib has the ability to que up commands as well. But that is not going to speed up apahche.:)
Another possible advantage to using a thread model is faster IPC. With something like Apache, there shouldn't be very much IPC going on except to dispatch a new request and possibly lock protect common files.
I have not looked at a single line of apache code, so I can't say for sure, but there seem to be a number of httpds running all the time, which would signify that it is using pooling. So why is it slower than the NT counterpart?
My email and phone # are at the top of my homepage (jc@). If you don't have javascript turned on it won't show up (spam protection).
Hmm. modulation for control sounds like a good idea, but I was hoping to use an off the shelf electric copter minus a battery pack. This way I don't have to change the control systems.
Also, eventually I would like try flying in more than one dimension which would require a pretty good tracking system. I was thinking of a mirror attached to spring & coil to direct the laser/microwaves. But to get the copter's position accurately you would want to do EM pulses and measure the reflection times. My worry is that you will not be able to track it continously and that for short periods of time it would have to rely on an alternate power source as well as communication. I suppose modulation would be ok as long as the microcontrollers held it in a stable state during these periods.
Right now I'm trying to find the best low wattage motor that can give enough torque for lift off and support the weight of a gyro and a small circuit board. It takes a lot more than I originally thought.
Actually microwave is about 2GHZ (~2.6 for microwave ovens), which is right below RF. Also microwave resonance is about the length of bird. Several environmental impact studies have been conducted on the effects of microwave on bird for this reason. Resonance cause them to heat up faster. When birds overheat in flight they drop their feet to cool off. By putting a bird in a wind tunnel and subjecting it to various levels of microwave, it was determined that power levels less than 50 mW/cm2 (I'm hope that is the right units!) had no effect on the birds. Microwave communication uses power level far less than this.
These studies did not access the potential of DNA breakage, just effects of heat. Because the length of a microwave is so long it would difficult for it effect DNA (which often results in cancerous growth). You should be much more worried about sunlight, which contains a fair amount of energy in ionizing spectrum. If you are then indoors type, sitting in front a monitor exposes you to x-rays which is also a bad spectrum to be exposed to. Even visible light is higher spectrum than microwave. There is no 100% effective way to avoid radiation induced cancer unless you live in a completely dark lead lined tank. Even then....
I'm currently looking into using laser/microwave for power transmission on a hobby project. For some links about this subject area, click on my sig. Anyone who has tried this, please write me.. I need help.:)
Ok, this is something I've wondering about. Has anyone investigated how to speed to do this for normal PCs? Where is all the time taken up during kernel boot? If you assume all the hardware hasn't changed from the last boot, is there anyway to quicky "play-back" io initialization and then load a memory image of the kernel?
I've been making a little robot with microprocessors, but I'd like to add some real CPU power without too much work. Using linux is the obvious choice, but boot time can be a pain if the bot shuts down frequently to save power.
Slashdot Mirror
I can't help but wonder if you managed to get through college without giving out your SSN. Where I went (U of Texas), practically everything required your SSN. Regisitration, Test, Homework Papers, Telephone Services, etc.
From my understanding of ITAR (the base set of regulations on munitions and cryptography products agreed to by most countries), it is always legal to import a product assuming the export is legal from the parent country (at least for cryptography products). This means if you can legally export something from the UK, then you can legally import it in the US. The problem here is that many products originate in the US and cannot be legally exported (except to Canada). So it is also illegal to import them elsewhere, because the export would have occured through illegal, though trival, means.
:)
On a totally different subject, I found out yesterday that a "crypologist" is a person who studies unknown animals, like bigfoot, lochness, etc. From this I take it "crypt" is the latin root for the unkown, and graphy is the practices/art of something? So cryptography really means "the art of the unkown." Sound like a some kind of cult activity.
Try newslinx.com. They have more news than you can handle, updated much more frequently than slashdot.
IIR, Intel has 40+ corportations just this reason. It's standard to create a new corp when opening a site up overseas. Each country has their own laws that could open you up to a lawsuit. By starting a new corp, you limit your liability to just the assests of that company. Also the taxes will be limited to that companies earning.
This is probably RedHat's primary motivation here, as they already sold in most countries already.
When I moved here last year, I looked at some apartments near Apple in Santa Clara. $3400 a month! Holy cow. It was less than 900sq ft. You can freakin buy a humongous mansion anywhere else for that kind of money. The funny thing is, I almost took the apartment.
I live in San Jose and a saw on the new a few weeks back that Santa Clara is now offering "low income housing loans" for people making under $100,000/year. As well, I recall that the richer part of Colorado Springs (or where the host ski spot is), also has low income housing loans for the poor saps making $100K.
What I want to know is, where is the *cheapest* place in the US to live including cost of a T1/cable modem? That's one thing you don't hear much in reports of housing out here. There are hundrededs (well probably not that many) of ISPs here and internet access is cheap because of the competition. Now, I don't think I could live anywhere that leaves me with a modem as my only option.
Uhh, what is a gamma channel? Gamma is traditionally associated with color calabration in computer graphics. However it is always applied as a single function over an entire image, meaning there is no need for a channel. Am I missing something?
Even without using something like this, disassembly of programs cannot be 100% correct. There is a lot of information needed to reconstruct a program that is thrown away by the compiler. For example you can't determine where a jump table (switch statement) or function pointer (virtual function) will lead to without actually executing the program and then it's not possible to cover all of the cases that could occur. IDA does a pretty good job of guessing though. Also IDA has hacks if it is looking at C code like looking for procedure frame headers (push ebp; mov ebp, esp) and termination code (pop ebp; ret). My solution to correct disassembly is to use emulation. This insures you never have an incorrect interpretation, but you will miss code that is never executed, and this can be important for understanding how errors and exceptions are handled.
Just because you can dissemble something doesn't mean you can understand it. It requires a huge amount of time to try to comprehend uses for unnamed memory locations and layout of data structures. In the case of a driver this is frustrated by the fact you are dealing with a lot of hidden code and data (the logic on the hardware). Not all drivers are "small pieces of code." Having looked at several vendor's Direct3d driver source code I can tell you each was extremely large and complex. Writing the driver with full knowledge of everything is hard enough, but disassembling one and understanding it would require super human willpower. There are all sort of commands that will do different things depending on that state of the card, so you have to understand what previously executed code was important to getting the card into that state.
I wonder if domain names will ever replace
trademarks? No need for lawyers, no complicated searches and forms to fill out. No accidental granting 2 people the same TM. Instantly internationally binding and automatically enforced. If you compared the convience domain names present over TMs, they are damn cheap.
The only thing that remains is an automatic image TM system for logos, etc. Perhaps you submit your logo in a vector format and it is compared using a yet to be invented standard algorithm to other registered images. If a match of X% probability occurs the image is rejected.
I am refering to functions like :
...)
DebugActiveProcess(), WaitForDebugEvent(), CreateProcess(... DEBUG_PROCESS
and also functions that manipulate other processes like:
VirtualAllocEx(), VirtualProctectEx()
Even stuff for your own process is missing, like GetThreadContext, and SetThreadContext.
All of these functions were missing last time I checked.
While I think they are heading in the right direction, it doesn't sound like they have gotten very far according to the article. Thus far they have only run a command-line program that uses very few system calls (the Borland compiler). Consider what is needed by a compiler:
CreateFile, CloseHandle, etc. - Minimal file operations
VirtualAlloc, GlobalAlloc, etc - Minimal memory management
Plus a half a dozen misc functions. They state in the article that they haven't even started on the GUI, perhaps the hardest part. You can't just clone a few bits kernel32.dll and winnt.dll and say you have a windows clone. They also make no mention of how they plan to implement DDK which, IMO, would be the whole point of making a windows clone. Without device drivers what good is an OS?
The WINE project is *way* beyond this. Also WINE benefits tremendously by having a linux core and thus a solid device driver base behind it. Having said that, there are 2 problems with Wine. The first will probably never be surmounted, and that it will never be able support hardware that has win32 only drivers, and many of the APIs Microsoft has developed don't exist under linux so even if someone was willing and able to port, they couldn't. Take Direct3d for example. The best you could hope is to make a D3D->GL layer inside WINE, but it's not a very good mapping. Then there are weirder things like : CryptoAPI, Telephony API, etc.. where there is nothing at all like it under linux.
The second problem with WINE is that it is a single process solution. It makes no attempts to emulate the entire system, just the current process. This means you can't : debug a process, drag and drop, and other forms of IPC that many programs depend on. I believe this can be fixed, but will require a fairly big change to WINE.
Another project to look at that is very interesting is the FX!32 system by DEC. This system actually runs under NT, so they didn't have to write APIs except to thunk from 64->32->64. But it can run native intel binaries with very little slow down by doing dynamic code translation.
(wow, I just noticed "Linux" is not the Microsoft Spell Checker)
Since we are on this topic, I'm trying to get people to test a program I made. This is Windows only right now, but it compresses a Win32 Executable and adds a stub program to it that decompresses the program in memory when it runs. This turns out to be a very tricky thing to do because of dll imports, resources, thread local storage, and so on. Anyway, if you have any programs that don't work with it, mail me...
compared to other micro boards used for robotics:
pros
- low power ussage when idle
- lots of ram (for the size)
- good number of io/ports. good for controlling servo motors and reading digital sensors.
- fairly fast. Probably good enough to do some image processing.
- ethernet useful for fast experimentation in tethered mode.
- nice environment to work in (linux!)
cons
- Needs at least one A/D converter.
- Wireless Ethernet would be more useful. Autonomous robots aren't going to be able to use plain ethernet.
This is not what is going to happen, but with 128 bit addresses you could just pick a number at random and use it. The odds of 2 people chosing the same number is low enough to be acceptable.
The actual probability is approx:
1- exp(-n*n/m)
where n is the number of addresses selected
and m is the total addresses available.
If 4 billion people select addresses at random then the odds of a collision are:
1 in 415,828,534,307,635,078.
To put this number in perspective, your odds of guessing the right number to a 56bit DES encryption key on your first try is 1 is much better:
1 in 72,057,594,037,927,936
We won't be running out of IP addresses anytime soon. 2^128 is not big enough that we could assign each atom on the planet is own IP address (this number is ~2^170), but we certainly could assign each atom that could possibly be seen it's own IP (i.e. by excluding those in the earth's core). Considering that you need a fair number of atoms to store just to store a 128bit number, I think we are safe until space travel explodes.
Thanks for the reiview for those of us not keeping up with the cpu wars.
Jonathan
Don't forget not everyone has English as a native language. Word is a fully internationized product. I find this very useful when writing emails in other languages. Who can remember all the tildes and accent marks? Spell as you go helps refresh your memory. Also since I have the no-can-spell birth defect, I find it help me a lot with english.
While it true that stories aren't stored on /., in many cases I never read the actual story. Besides the fact the site is probably slashdotted, I'm more interested in what people here have to say about a topic. Often you will get much more information here than is presented in the article, so it is a waste of time to read them.
/. exercise brevity and with moderation it's easy to read according to how much free time you have, unlike external articles that require good skimming skills to find useful information.
People on
While the accuracy of information here is not as well researched, it usually doesn't need to be because it is written by engineers who know what they are talking about. Journalist generally aren't engineers.. consider the salary differences.
I see the stories simply as a focus point of conversation, and it is Rob who is picking the conversations, not the journalist. There are literally several hundred online articles published daily by major papers, most of them don't provide much new information.
"The United States launched its first comet mission in February -- the Stardust spacecraft, which is to pass within 140 km (90 miles) of the Comet Wild-2 in January 2004. The mission hopes to be the first to capture dust from a comet and return it to Earth in 2006. "
Ok this is off topic, but, can anyone confirm or deny that the Stardust Casino and Hotel is actually named after abomb fallout, because it was constructed during the period of time when atomic testing occured in Nevada? I have a long standing bet with a friend, and we can't nail this down. I read this a long time ago, but can't find it now. If you look at the stardust sign with all the lights, it looks like an abomb..
Hmm. I'm note sure about this, any IP lawyers around? First of all, of the stories about companies posted on /. are not all positive. In fact, many are negative are accompanied with what could be construed as liabacious (from AC posters). In these cases, it is probably the case the companies don't say anything because the don't want to cause further bad press, or they (their lawyers at least) are just not aware of /. IIR, in a recent case is was decided in playboys favor against people using the word playboy in META tags. In most cases the META tags are not seen by the end user, so there is no mistaking the site for the real company. However they were deriving a profit (through increased traffic) through the use of the mark. I see a parallel on /. I think it would be a good idea to put a "X is a trademark of X" somewhere on /. to cover your butt. Even if you are not making a profit, you can infringe on a trademark. I think there is a good reason why newspaper stories almost always attribute any tm they display.
I've been reading the comments and I am really surprised there isn't much backlash. ./ers are famous for shooting down anyone who becomes sucessful.
./ There is use of trademarks on the front page (for example today we see SGI's logo). Often the trademark is not attributed to the owner of the mark. Now that another company is responsible for you legally, while you have to change some policies that could put them at legal risk, such as this and anonymous posters.
:)
Anyway, congrats!
I've always wondered about one thing about
So what was the sales price (ballpark?) It'll come out soon enough...
What are you saying? Spell as you go is my favorite feature of all time! Mainly because I cannot spell. And it is done very well, the editor doesn't "nag" you as you claim. It does jaggy underlines in red, which is easy to ignore if you don't care.
And unlike 'check everything at the end', spell as you go lets you improve your spelling skills at the time when you are thinking about it.
I still use emacs for programming... if it had spell as you go I would use it for text editing as well. Without wysiwyg and a graphical interface drafting a business letter with graphics would be extremely hard in emacs. Also let's not forget printing....
I don't know that Samba and Apache selected the forking model by choice. Not to long ago threads really didn't work under linux, so there was no choice. I had a similar experience while working on a video game called Golgotha. We *really* had to have threads, but they didn't exists or didn't work properly.
:)
The kernel has had fundamental support for them for a longer period of time, but a reliable thread safe libc (and libX11) did not surface until recently (the last year or so). Even now the distributions are struggling to get everything converted over to the new glibc.
Even though linux now has good thread support, gdb has trouble with them (last time I checked, which was a while back). Also, apache and samba are not linux-only products. The safest and most portable approach to take back then was to use a forking model.
Other than taking up an too much memory and thus causing swapping, I don't see why a threaded model would be any faster than forking model if pooling is used. Pooling keeps a fixed number of processes running all the time and dispatches request to them. When they finish they sleep and wait for the next request. This way you have the safety of a separate process space and you avoid the forking (as in you "forking piece of sheet") over head. You let each pooled process have a fixed lifetime in order to clean up any leaked memory. Some systems have libc leaks that can't be avoided, so this is important to long-term stability.
You might argue that a thread context switch is less expensive than a process context switch. Under NT (and 95), all threads are scheduled without regard to what process they belong to, so at most could skip some page table changes when going from one thread to the next. I doubt that is the case, because threads jump from ring3 to ring0 and back while executing system functions (ensuring they have different page tables). Also threads have a separate segment mapping for fs. A 3->0->3 context switch is accomplished by an interrupt in NT. One way to speed things up in linux might be to have a way to pool system request up in ring3 and then dispatch them all at once in ring0. NT did this with their GDI code. Doing this for all system calls wouldn't require a huge change in the kernel, but it would make user code harder to write as system calls have to be parallelized. GDI doesn't require any changes to user level code, because there are no return codes to worry about for graphic drawling operations. Xlib has the ability to que up commands as well. But that is not going to speed up apahche.
Another possible advantage to using a thread model is faster IPC. With something like Apache, there shouldn't be very much IPC going on except to dispatch a new request and possibly lock protect common files.
I have not looked at a single line of apache code, so I can't say for sure, but there seem to be a number of httpds running all the time, which would signify that it is using pooling. So why is it slower than the NT counterpart?
My email and phone # are at the top of my homepage (jc@). If you don't have javascript turned on it won't show up (spam protection).
Hmm. modulation for control sounds like a good idea, but I was hoping to use an off the shelf electric copter minus a battery pack. This way I don't have to change the control systems.
Also, eventually I would like try flying in more than one dimension which would require a pretty good tracking system. I was thinking of a mirror attached to spring & coil to direct the laser/microwaves. But to get the copter's position accurately you would want to do EM pulses and measure the reflection times. My worry is that you will not be able to track it continously and that for short periods of time it would have to rely on an alternate power source as well as communication. I suppose modulation would be ok as long as the microcontrollers held it in a stable state during these periods.
Right now I'm trying to find the best low wattage motor that can give enough torque for lift off and support the weight of a gyro and a small circuit board. It takes a lot more than I originally thought.
Actually microwave is about 2GHZ (~2.6 for microwave ovens), which is right below RF. Also microwave resonance is about the length of bird. Several environmental impact studies have been conducted on the effects of microwave on bird for this reason. Resonance cause them to heat up faster. When birds overheat in flight they drop their feet to cool off. By putting a bird in a wind tunnel and subjecting it to various levels of microwave, it was determined that power levels less than 50 mW/cm2 (I'm hope that is the right units!) had no effect on the birds. Microwave communication uses power level far less than this.
:)
These studies did not access the potential of DNA breakage, just effects of heat. Because the length of a microwave is so long it would difficult for it effect DNA (which often results in cancerous growth). You should be much more worried about sunlight, which contains a fair amount of energy in ionizing spectrum. If you are then indoors type, sitting in front a monitor exposes you to x-rays which is also a bad spectrum to be exposed to. Even visible light is higher spectrum than microwave. There is no 100% effective way to avoid radiation induced cancer unless you live in a completely dark lead lined tank. Even then....
I'm currently looking into using laser/microwave for power transmission on a hobby project. For some links about this subject area, click on my sig. Anyone who has tried this, please write me.. I need help.
Ok, this is something I've wondering about. Has anyone investigated how to speed to do this for normal PCs? Where is all the time taken up during kernel boot? If you assume all the hardware hasn't changed from the last boot, is there anyway to quicky "play-back" io initialization and then load a memory image of the kernel?
I've been making a little robot with microprocessors, but I'd like to add some real CPU power without too much work. Using linux is the obvious choice, but boot time can be a pain if the bot shuts down frequently to save power.
Inquiring minds want to know...