And, girls get out of class, and half of them whip out their phones for a quick chat between classes. Most of them have trouble operating a PC. What would they do with a PDA?
It becomes obvious to the point of redundancy to say:
Me? I don't leave the house (besides work and school) enough
This article isn't about a general comment as to how software should be written; it's about implementing protocols. And protocols have to be defined by specifications -- you can't simply have some vague spec that says "it should do approximately this"; you have to precisely define the language of the protocol so that everyone knows what they are implementing.
That being said, Ted Ts'o makes the most important comment in the discussion: This is the reason for the IETF Maxim --- be conservative in what you send, liberal in what you will accept. In other words, when your code talks over the protocol, be minimalist and adhere strictly to the spec; but if you can implement your code in such a way that it is tolerant of small variances (e.g. combinations of commands which make sense but are not allowed by a strict interpretation of the protocol spec) and can do it safely, then you should. This is the approach I've always taken, and having done things like implement a major printer vendor's IPP server, I have found this approach makes interoperability and compatibiltiy a lot easier and less painful to achieve.
So at least from that standpoint, I think I can see what Linus is trying to say; at any rate I agree that strictly adhering to a spec simply for reasons of mathematical correctness is not always the most productive route.
All of this kind of reminds me of another stupid disc format which fell on its face. And it did so mostly due to consumer outrage:
The idea of a system designed for metered disc viewing enraged many film buffs and home theater hobbyists, and a virulent anti-Divx campaign erupted on the Internet. Warner Home Video, a driving force behind the sell-through-oriented DVD format, wanted to derail Divx (perhaps in part because it wanted to thwart competition for its upcoming video-on-demand system). Video rental firms opposed Divx because it threatened to disrupt a lucrative revenue stream: late fees.
Protected Video Path - Macular Interface Neural Encryption (PVP-MINE) provides encryption of premium content as it passes between the user's retina and the visual centers of the user's brain. This is required when the content owner's policy regards the optic nerve as a user-accessible bus. Convenient sight management implants allow content owners to manage their media rights without unnecessarily encumbering the user's computer system.
Despite all the skepticism being bandied about military technology on this site, automated carrier landings are not new. The first fully automated landing on an aircraft carrier took place on Aug. 12, 1957, when an F3D Skyknight was landed on USS Antietam (CVA 36) at sea off Pensacola, Fla., by the Automatic Carrier Landing System (ACLS). That's right, over 40 years ago. That system is still in wide use today, and is only now slowly being replaced by the JPALS (Joint Precision Approach and Landing System) system which uses GPS instead of the radar used by ACLS.
The QinetiQ system described in the article (which is itself a component of JPALS) is remarkable in that it automates vertical landings. I'm kind of uncertain as to why that had never been done before, though I think it has more to do with the much lower level of interest, and therefore funding, than because of any technical challenge.
Is it just me, or is it impossible to filter out the politics section?
I went into my Preferences, on the Home Page, and checked that I wanted to gnore the Politics, Democrats, and Republicans topics under Exclude Stories from the Homepage. And yes, I hit Save. Nevertheless, these stories keep appearing.
For the money, I think the Sharp Actius MM20 is a better machine. Same 1GHZ Efficeon processor, but 512mb of RAM, built in ethernet, wifi, pc card slot, and 2 usb ports, and the screen is 10.1" instead of the tiny 7". It still only weighs 2 lbs, and costs quite a bit less. By itself it's $1500; there's an optional external USB DVD/CDRW drive for $99, and for an addtional $200 you get a long run battery which gives up to 9 hours of runtime.
Best of all, everything works in Linux -- Emperor Linux sells this as the Meteor, although IMO they tack on too much of a premium. But you can find do it yourself Linux install instructions for several distros at Linux on Laptops.
The specific languages that Graham and Hejip compare to Java are irrelevant; I was citing a reason for Java's perceived un-coolness and used C as an example of a language without Java's perceived shortcomings in that regard. I'd also recommend that you read the Graham article more carefully, as he does indeed mention C, right here:
If Microsoft used this approach, their software wouldn't be so full of security holes, because the less smart people writing the actual applications wouldn't be doing low-level stuff like allocating memory. Instead of writing Word directly in C, they'd be plugging together big Lego blocks of Word-language.
To put that passage in context, he's talking about a bottom up approach, and how the "great hackers" should be used as tool makers, building the Duplo blocks that the less talented people can use to assemble applications.
It's just not that hard to understand this. For good or ill, programming has always been an ego-driven profession. You hear stories of punch cards and marathon hacking sessions, and how cool it was that some guy arranged all of his code so that memory accesses were precisely in alignment with the rotation of the memory drum. You do not hear about how cool the fact that someone's applet can't crash because of automated bounds checking and lack of explicit pointers.
Java is seen as uncool precisely because it protects you from your own mistakes -- it's an attempt to make programming approachable to the masses, and the fact that it's forgiving makes it look like programming with training wheels. And just like the 50 year old MBA will never fit in with the Harley crowd, Java programming will never be seen as cool as "real" hackers' languages like C.
The military coup would have happened whether or not the US supported it. The US was prepared to send arms and other aid to the Brazilian military because they feared that without US aid the revolution would turn into a protracted and bloody affair. As it turns out, the military had broad support among the people and the coup was basically bloodless. The bloodshed came later when the military was in power.
The point, in any case, is that Brazil is hardly a shining example of peace that the US should learn from. Their government may not be involved in hostilities with other nations, but it certainly perpetrates its share of violence.
However, it has been more than 100 years since the Brazilian government has been involved with aggression against its neighbors.
Other than World War II, that's basically true. But it's convenient to omit that Brazil's civilian government was deposed in a military coup in 1964, civilian rule was only restored in 1985, and in the meantime death squads and terrorism were a fact of life in Brazil. And despite a return to civilian government, death squads and otehr violence sponsored by the Brazilian government against its own citizens continues to this day.
Isn't it funny how, in the dot-com boom of the roaring 90's, "disintermediation" was the buzzword for the phenomenon that was going to make everyone super rich? Cut out the middleman, allow shoppers to directly access your site, and watch the dough roll in.
And isn't it great how the most successful web businesses, like Yahoo, Amazon, eBay, and Google, are all busy making money through "intermediation", acting as the middleman who points buyers to sellers, and making money by selling ad space and transaction fees?
Just FYI, plugin support has worked since at least RealPlayer version 8.
I currently have RP8 + the RP9 codecs installed on slackware 10, and plugin support works just fine. You just need to put raclass.zip and rpnp.so in your mozilla plugins/ dir, and make sure that "realplay" is in your PATH, and it works fine.
Between that and mplayerplugin, I'm all set for media types. I'll consider upgrading to RP10 when I find something I can't watch with RP8/9.
Oh, and didn't you have some problems with civil rights in the southern states in the 60's ?
Yes, we did, and that really is an illustration of jgardn's post. Notice how many laws have been passed since then to enforce civil rights and equality. Those came about because people took action, not because the government happily saw the error of its ways. But because the US is a democracy, and because people have freedom of political speech here, changes came about and those "problems" with civil rights in the south eventually were dealt with. No, we still don't have perfect racial harmony or equality. But at least from a legal perspective, we do. Now it's up to citizens to do the rest, not the government.
Incidentally, his point about the Second Amendment is well taken in this context as well: a lot of blacks in the South benefited from being able to bear arms, to defend themselves against groups like the Ku Klux Klan which opposed their fight for equality.
If you choose to run a distro which doesn't do things like install CUPS and Ghostscript, then you've chosen to do those things yourself if you want to print. If you find this too difficult, use a Linux distribution more suited to your skill level.
I recently installed Fedora Core 1 for a coworker who wanted to try Linux but thought something like Slackware (what I run) looked too daunting.
I got his printer working by opening the printer control applet and selecting the printer type and connection. Sharing it with SMB and LPD clients was equally trivial and all accomplished with the GUI. Nothing to install, no files to edit, nada.
Wake up and smell the coffee guy!! We are now well into the 21st Century and you're still using a distribution that appears to have been developed in the 1990's.
As everyone knows, DSL speed is limited by wire distance from the local telco Central Office or Remote Terminal. A couple of summers ago, SNET (Connecticut independent phone company, now assimilated by SBC) was having a lot of trouble with bad DSL performance. They had wildly oversold their bandwidth and the service was almost unuseable between 5PM and 9PM, peak gaming hours. Faced with a barrage of calls from angry customers, telephone tech support people were telling callers that the reason for their DSL trouble was that the summer heat was stretching the telephone wires, which increased their effective distance to the CO/RT and therefore slowing down their traffic. As the lines cooled in the evening, they shrank again and performance returned.
I went to the manufacturer's website and found it interesting. Some of their ideas are great -- particularly the tailgate warning feature. In general, the products actually described on their web site are great ideas and would definitely make driving safer.
However, none of those products seem to involve cameras or any kind of specific-vehicle identification. I'm disappointed in that, as I was really curious as to how they supposedly accomplish licence-plate captures. I've worked on a number of Electronic Toll Collection projects, including the world's first high-speed system, and setting up cameras for capturing images of vehicles moving at freeway speeds clear enough to read the licence plate is not trivial. Granted, the proximity to the vehicle would help -- most of the systems I work with use a camera off to the side, which requres taking images of vehicles some distance away to compensate for the angle -- but to mount those kinds of optics into a package that small... I'd have to see it to believe it.
If you read the story, you'd see that this is in no way a state-wide issue, but a single municipality. The town, as it turns out, is one of the wealthiest per capita in the United States, and its citizens have recently suffered a rash of burglaries and other crimes. They demanded additional protection to curb these problems, and their tax dollars paid for this system among other things.
If you don't like this, you have no obligation to go there - it's not like an interstate passes through it or anything like that. In fact, it's on one of the barrier islands near Palm Springs.
Shouldn't there be a #include after the #include ? The extern variable environ is available only if unistd.h has been included.
Nope. unistd.h declares extern char **environ, so if you do not #include that header, your code needs to declare the variable. The example program does that, so this is OK in this case.
I would argue that it's never very good practice to declare by hand things that are declared in header files, because the implementation can change -- witness the problems caused recently when errno became a macro, yet lots of code which used it failed to properly #include errno.h. But I'm guessing the example was coded this way for clarity.
While I am talking about this example, it could have used int main(void) instead of...(int argc, char **argv) (like he does in ch03-getline.c).
It's interesting to notice that in these tests, the Opterons were clocked quite a bit slower and had a lot less cache than the Intel CPUs, yet performed comparably in 2-way and better in 4-way than the Intel chips.
The Opteron clocked at 2.2ghz with 1MB of cache was very close in 2-way performance with the Xeon 3.0 and 3.2 ghz each with 4 and 2 mb of cache respectively. The 1.8ghz Xeon compared well with the Xeon 2.8ghz with 2MB of cache. The Opterons were typically within 3% or so of their Intel counterparts in 2-way benchmarks and closer to 10% ahead in 4-way.
If nothing else, this says a lot about the efficiency of the Opteron's design. Less silicon, and more importantly for AMD, less expensive silicon, manages to achieve very close results.
Can we please stop letting people use slashdot to increase the hit rate on their articles in order to make themselves seem relevant to their bosses?
Fred moody, the infamous anti-Linux ABC News columnist, was doing the exact same thing four years ago. In fact, he was writing on pretty much the same subject, that Open Source is insecure and untrustworthy by its very nature.
Those who do not study history are doomed to repost it.
Second, it's not as simple as saying, "that's where people want to live, too bad." Silicon Valley is built on the best farmland in California, possibly in North America. The early electronic factories didn't come here for easy access to food -- they came here to be near Stanford and the Moffett Naval Air Station.
Yes, I remember tales of the pioneers of the 1800s hitching up the Conestoga and braving the crossing of the great plains in their brave quest to live near Stanford and Moffett Field, visions of higher learning and F-14s dancing in their heads as they struggled to ford streams with their teams of oxen...
One of my favorite projects in my sophomore operating systems class at university was to implement various little toy programs on Jean Labrosse's uCOS realtime operating system to illustrate various OS features like IPC and multitasking.. We did things like implement a "horse race" with two "horse" threads moving across the screen and an "announcer" thread which displayed positions, all synchronized by semaphores and communicating through mailboxes. Nothing earth shattering, but since the code for each thread and the related OS code was only a couple of pages of text, it made for a great presentation. Enough code to be fully functional, but not so much as to cause anyone to get lost.
The nice thing about uCOS is that it is a very clean design that runs on simple platforms and can run as a task under another OS. We ran it on a 8mhz 286 running DOS. The source code is clean and well-commented, and there are a number of books written by the author which do a good job explaining the design and implementation and come with the complete source. It's a great way to see a simple implementation of task management on an OS and get a solid footing in the basics before delving into something like BSD or Linux.
Slashdot Mirror
When you make a comment like:
And, girls get out of class, and half of them whip out their phones for a quick chat between classes. Most of them have trouble operating a PC. What would they do with a PDA?
It becomes obvious to the point of redundancy to say:
Me? I don't leave the house (besides work and school) enough
This article isn't about a general comment as to how software should be written; it's about implementing protocols. And protocols have to be defined by specifications -- you can't simply have some vague spec that says "it should do approximately this"; you have to precisely define the language of the protocol so that everyone knows what they are implementing.
That being said, Ted Ts'o makes the most important comment in the discussion: This is the reason for the IETF Maxim --- be conservative in what you send, liberal in what you will accept. In other words, when your code talks over the protocol, be minimalist and adhere strictly to the spec; but if you can implement your code in such a way that it is tolerant of small variances (e.g. combinations of commands which make sense but are not allowed by a strict interpretation of the protocol spec) and can do it safely, then you should. This is the approach I've always taken, and having done things like implement a major printer vendor's IPP server, I have found this approach makes interoperability and compatibiltiy a lot easier and less painful to achieve.
So at least from that standpoint, I think I can see what Linus is trying to say; at any rate I agree that strictly adhering to a spec simply for reasons of mathematical correctness is not always the most productive route.
Protected Video Path - Macular Interface Neural Encryption (PVP-MINE) provides encryption of premium content as it passes between the user's retina and the visual centers of the user's brain. This is required when the content owner's policy regards the optic nerve as a user-accessible bus. Convenient sight management implants allow content owners to manage their media rights without unnecessarily encumbering the user's computer system.
Despite all the skepticism being bandied about military technology on this site, automated carrier landings are not new. The first fully automated landing on an aircraft carrier took place on Aug. 12, 1957, when an F3D Skyknight was landed on USS Antietam (CVA 36) at sea off Pensacola, Fla., by the Automatic Carrier Landing System (ACLS). That's right, over 40 years ago. That system is still in wide use today, and is only now slowly being replaced by the JPALS (Joint Precision Approach and Landing System) system which uses GPS instead of the radar used by ACLS.
The QinetiQ system described in the article (which is itself a component of JPALS) is remarkable in that it automates vertical landings. I'm kind of uncertain as to why that had never been done before, though I think it has more to do with the much lower level of interest, and therefore funding, than because of any technical challenge.
Is it just me, or is it impossible to filter out the politics section?
I went into my Preferences, on the Home Page, and checked that I wanted to gnore the Politics, Democrats, and Republicans topics under Exclude Stories from the Homepage. And yes, I hit Save. Nevertheless, these stories keep appearing.
Heh but I spoke too soon. There was also a Venturcom Venix that ran on PDP's.
I used the x86 version in the mid 90's, and had never heard of the PDP one.
Venturcom Venix was a System V derivative for x86 PC's. It's basically an early revision of SCO Unix with realtime extensions.
There were plenty of regular AT&T Unix versions that ran on PDP-11s though.
For the money, I think the Sharp Actius MM20 is a better machine. Same 1GHZ Efficeon processor, but 512mb of RAM, built in ethernet, wifi, pc card slot, and 2 usb ports, and the screen is 10.1" instead of the tiny 7". It still only weighs 2 lbs, and costs quite a bit less. By itself it's $1500; there's an optional external USB DVD/CDRW drive for $99, and for an addtional $200 you get a long run battery which gives up to 9 hours of runtime.
Best of all, everything works in Linux -- Emperor Linux sells this as the Meteor, although IMO they tack on too much of a premium. But you can find do it yourself Linux install instructions for several distros at Linux on Laptops.
To put that passage in context, he's talking about a bottom up approach, and how the "great hackers" should be used as tool makers, building the Duplo blocks that the less talented people can use to assemble applications.
Have fun with your Lego.
It's just not that hard to understand this. For good or ill, programming has always been an ego-driven profession. You hear stories of punch cards and marathon hacking sessions, and how cool it was that some guy arranged all of his code so that memory accesses were precisely in alignment with the rotation of the memory drum. You do not hear about how cool the fact that someone's applet can't crash because of automated bounds checking and lack of explicit pointers.
Java is seen as uncool precisely because it protects you from your own mistakes -- it's an attempt to make programming approachable to the masses, and the fact that it's forgiving makes it look like programming with training wheels. And just like the 50 year old MBA will never fit in with the Harley crowd, Java programming will never be seen as cool as "real" hackers' languages like C.
The military coup would have happened whether or not the US supported it. The US was prepared to send arms and other aid to the Brazilian military because they feared that without US aid the revolution would turn into a protracted and bloody affair. As it turns out, the military had broad support among the people and the coup was basically bloodless. The bloodshed came later when the military was in power.
The point, in any case, is that Brazil is hardly a shining example of peace that the US should learn from. Their government may not be involved in hostilities with other nations, but it certainly perpetrates its share of violence.
However, it has been more than 100 years since the Brazilian government has been involved with aggression against its neighbors.
Other than World War II, that's basically true. But it's convenient to omit that Brazil's civilian government was deposed in a military coup in 1964, civilian rule was only restored in 1985, and in the meantime death squads and terrorism were a fact of life in Brazil. And despite a return to civilian government, death squads and otehr violence sponsored by the Brazilian government against its own citizens continues to this day.
Isn't it funny how, in the dot-com boom of the roaring 90's, "disintermediation" was the buzzword for the phenomenon that was going to make everyone super rich? Cut out the middleman, allow shoppers to directly access your site, and watch the dough roll in.
:)
And isn't it great how the most successful web businesses, like Yahoo, Amazon, eBay, and Google, are all busy making money through "intermediation", acting as the middleman who points buyers to sellers, and making money by selling ad space and transaction fees?
I love it when a plan comes together
Just FYI, plugin support has worked since at least RealPlayer version 8.
I currently have RP8 + the RP9 codecs installed on slackware 10, and plugin support works just fine. You just need to put raclass.zip and rpnp.so in your mozilla plugins/ dir, and make sure that "realplay" is in your PATH, and it works fine.
Between that and mplayerplugin, I'm all set for media types. I'll consider upgrading to RP10 when I find something I can't watch with RP8/9.
Oh, and didn't you have some problems with civil rights in the southern states in the 60's ?
Yes, we did, and that really is an illustration of jgardn's post. Notice how many laws have been passed since then to enforce civil rights and equality. Those came about because people took action, not because the government happily saw the error of its ways. But because the US is a democracy, and because people have freedom of political speech here, changes came about and those "problems" with civil rights in the south eventually were dealt with. No, we still don't have perfect racial harmony or equality. But at least from a legal perspective, we do. Now it's up to citizens to do the rest, not the government.
Incidentally, his point about the Second Amendment is well taken in this context as well: a lot of blacks in the South benefited from being able to bear arms, to defend themselves against groups like the Ku Klux Klan which opposed their fight for equality.
If you choose to run a distro which doesn't do things like install CUPS and Ghostscript, then you've chosen to do those things yourself if you want to print. If you find this too difficult, use a Linux distribution more suited to your skill level.
I recently installed Fedora Core 1 for a coworker who wanted to try Linux but thought something like Slackware (what I run) looked too daunting.
I got his printer working by opening the printer control applet and selecting the printer type and connection. Sharing it with SMB and LPD clients was equally trivial and all accomplished with the GUI. Nothing to install, no files to edit, nada.
Wake up and smell the coffee guy!! We are now well into the 21st Century and you're still using a distribution that appears to have been developed in the 1990's.
As everyone knows, DSL speed is limited by wire distance from the local telco Central Office or Remote Terminal. A couple of summers ago, SNET (Connecticut independent phone company, now assimilated by SBC) was having a lot of trouble with bad DSL performance. They had wildly oversold their bandwidth and the service was almost unuseable between 5PM and 9PM, peak gaming hours. Faced with a barrage of calls from angry customers, telephone tech support people were telling callers that the reason for their DSL trouble was that the summer heat was stretching the telephone wires, which increased their effective distance to the CO/RT and therefore slowing down their traffic. As the lines cooled in the evening, they shrank again and performance returned.
I went to the manufacturer's website and found it interesting. Some of their ideas are great -- particularly the tailgate warning feature. In general, the products actually described on their web site are great ideas and would definitely make driving safer.
However, none of those products seem to involve cameras or any kind of specific-vehicle identification. I'm disappointed in that, as I was really curious as to how they supposedly accomplish licence-plate captures. I've worked on a number of Electronic Toll Collection projects, including the world's first high-speed system, and setting up cameras for capturing images of vehicles moving at freeway speeds clear enough to read the licence plate is not trivial. Granted, the proximity to the vehicle would help -- most of the systems I work with use a camera off to the side, which requres taking images of vehicles some distance away to compensate for the angle -- but to mount those kinds of optics into a package that small... I'd have to see it to believe it.
If you read the story, you'd see that this is in no way a state-wide issue, but a single municipality. The town, as it turns out, is one of the wealthiest per capita in the United States, and its citizens have recently suffered a rash of burglaries and other crimes. They demanded additional protection to curb these problems, and their tax dollars paid for this system among other things.
If you don't like this, you have no obligation to go there - it's not like an interstate passes through it or anything like that. In fact, it's on one of the barrier islands near Palm Springs.
Shouldn't there be a #include after the #include ? The extern variable environ is available only if unistd.h has been included.
...(int argc, char **argv) (like he does in ch03-getline.c).
Nope. unistd.h declares extern char **environ, so if you do not #include that header, your code needs to declare the variable. The example program does that, so this is OK in this case.
I would argue that it's never very good practice to declare by hand things that are declared in header files, because the implementation can change -- witness the problems caused recently when errno became a macro, yet lots of code which used it failed to properly #include errno.h. But I'm guessing the example was coded this way for clarity.
While I am talking about this example, it could have used int main(void) instead of
You should never use int main(void).
size is declared size_t, so it should be printed with %z
Yup, you are correct. It should not be cast to unsigned long, however.
I also agree with you about the other examples, especially regarding the alloca cast.
It's interesting to notice that in these tests, the Opterons were clocked quite a bit slower and had a lot less cache than the Intel CPUs, yet performed comparably in 2-way and better in 4-way than the Intel chips.
The Opteron clocked at 2.2ghz with 1MB of cache was very close in 2-way performance with the Xeon 3.0 and 3.2 ghz each with 4 and 2 mb of cache respectively. The 1.8ghz Xeon compared well with the Xeon 2.8ghz with 2MB of cache. The Opterons were typically within 3% or so of their Intel counterparts in 2-way benchmarks and closer to 10% ahead in 4-way.
If nothing else, this says a lot about the efficiency of the Opteron's design. Less silicon, and more importantly for AMD, less expensive silicon, manages to achieve very close results.
Mod story down (-1, troll).
Can we please stop letting people use slashdot to increase the hit rate on their articles in order to make themselves seem relevant to their bosses?
Fred moody, the infamous anti-Linux ABC News columnist, was doing the exact same thing four years ago. In fact, he was writing on pretty much the same subject, that Open Source is insecure and untrustworthy by its very nature.
Those who do not study history are doomed to repost it.
Second, it's not as simple as saying, "that's where people want to live, too bad." Silicon Valley is built on the best farmland in California, possibly in North America. The early electronic factories didn't come here for easy access to food -- they came here to be near Stanford and the Moffett Naval Air Station.
Yes, I remember tales of the pioneers of the 1800s hitching up the Conestoga and braving the crossing of the great plains in their brave quest to live near Stanford and Moffett Field, visions of higher learning and F-14s dancing in their heads as they struggled to ford streams with their teams of oxen...
One of my favorite projects in my sophomore operating systems class at university was to implement various little toy programs on Jean Labrosse's uCOS realtime operating system to illustrate various OS features like IPC and multitasking.. We did things like implement a "horse race" with two "horse" threads moving across the screen and an "announcer" thread which displayed positions, all synchronized by semaphores and communicating through mailboxes. Nothing earth shattering, but since the code for each thread and the related OS code was only a couple of pages of text, it made for a great presentation. Enough code to be fully functional, but not so much as to cause anyone to get lost.
The nice thing about uCOS is that it is a very clean design that runs on simple platforms and can run as a task under another OS. We ran it on a 8mhz 286 running DOS. The source code is clean and well-commented, and there are a number of books written by the author which do a good job explaining the design and implementation and come with the complete source. It's a great way to see a simple implementation of task management on an OS and get a solid footing in the basics before delving into something like BSD or Linux.