I think this is actually the fastest most compact way possible to encode information. It all depends on how good the compilers are. What they've done is replaces a generalized system like XML with custom written code that works only for the specific messages that are being passed. Nothing could be faster. The objection has always been that writing the custom code is hard. They have solved that issue.
No, you are only half right. An electric car not only moves the point where energy to produced from the car itself to the electric plant. But in doing so it uses to net total od far less energy. A gas powered car at most uses only 20% of the energy in the gas. the rest goes to heating air. A power plant on the other hand is much better
"Never going to happen. Nothing will ever beat the private car for convenience."
True ONLY in low-density areas. As soon as the number of people per square area goes up to some threshold cars are such a hassel that they become useless even if fuel were free. The problem is road conjestion and parking. Yes you can build huge parking lots and make more roads but this only makes the travel times longer becuase the city has to be much larger. Your typical suburb has more area devoted to cars than to buildings so EVERYTHING is spread out. If you loose all those cars then most places you need to go you can walk to.
I think the ideal design would be for dense urban areas each surrounded by open land
Technolgy can (some day) help. many in 25 years cars can drive them selves. Thenthey can travel on the road with only inches between bumbers and we don't need traffic lights as the cars can "weave" through intersections without stoping. Speeds can be very fast because the cars do not need to "react" becasue they know in advance what every other car is going to do, they comunicate.
Also you can share a car because it can drive itself to the next pick up point. like a driverless taxi. We would not need parking lots.
OK, if not in 25 years than in 100 years. I'm certain that with expensive energy and cheap computers a driverless taxi system and less space wasted with parking lots.
Solves the re-fueling problem too. The car just goes off and gets fuel itself
I had this same problem was compressed natural gas tanks. These are used for stove fuel on some sailboats.
The way to solve this problem is that you never buy a nice new battery. The cars are sold with just some random used battery the deal puts in. The car dealers just order them from the same place you'd go to swap them. You just pay a deposit once when you buy the car. Later you are charge for the "power" in the battery. If you get one that only holds 80% charge you pay for 80% of the full price.
Going with one framework simple can't work if you need to do a wide rang of work. For example I've worked on embedded microcontrollers where you have only a few kilobytes of RAM. I've worked on radar systems that used large mainframes as a processing engine and new rocket telemetry. There is no way the same tools could work on those three jobs.
But on the other hand if all you do is general office apps on a PC. Yes then standardize on a few tools
"Now it seems the majority have always thought he was guilty as Hell? Good grief!"
The majority can think different things and there be no conflict. The reason is that we have a different group of people. The set of people expressing opinion has likely changed. This is common problem with web-based surveys people are not selected at random but "self select" based on their level of interest so you end up with a very biased sample that does not refect the general population. This effect is very big here on slashdot.
If a person could wholly be inside a plane mentally (in a sense), imagine the increased control one could have,
We can do that now. If you think of the World War III Scenario, a major conflict in Europe. Piloted planes were to be flown on instruments. In europe the skies are not clear. Also with the speed of moderd planes you can't see the other plane except by instrumnets.
I worked on the B1 bommer project. One interresting feature of the plane were the aluminum panels that could fitted to the insides of the windows. Then you could not see out. This is the way the plan is designed to be flown when there are nuclear weapons being used. I suspect the B1 is not the only plane equipted with metal pannels. It is the only way to block EMP.
So now I ask what is the defference between flying inside a simulator in Kansas or in a real plan with blacked out windows except for the degree of risk to the crew. In both cases flying means punching in commands to an autopilot and reacting to various threats detected by instruments.
The days of looking through a gun site and shooting a machine gun at other airplans are long gone. It was 40 years out of date even when the first Star Wars movie was new.
most of the code out there is sequential (or nearly so) and I/O bound. So your home user checking his email, running a web browser, etc is not going to benefit much from having all that compute power. (Gamers are obviously not included in this) Thus, he predicted, processors would max out at a "relatively" low number of cores - 64 was his prediction.
Yes in 2020 if people are still doing those tasks all they would need were a "few" cores. But what if your email program actually tried t understand the text of the mail and tried to decide for you what you might be interested in? That is a HUGE and complex task that could use many, many cores per email message. Parsing the text and matching it into some kind of big semantic network is a non-trivel task. Next, what if your computer in 2020 had a web cam attached and used hand motion and lip reading as input. That alone could keep many cores bussy. Say nothing about voise input and output. And what if the company's PBX system actually answeredthe phone and talked with users and understadd simple things like "tell susan the meeting is at 2 not 3." and then the phone whould find susan and tell her.
OK my point is that if you had 1,000+ core you could do tasks you can't do now, like lip reading and answring 250 incoming calls all at once.
Ho, and what about controlling that walking robot that needs to carry your beer up the stairs? The robiot must have 1,000+ motors and sensors inside of it. One core, one thread per sonsor or motor.
THis is simply caching the results of a search. The cache gives a 10% speed up over re-doing each search. The smart thing here is finding a way the tag or label the cache so that to searches are recognized as being the equivalent if they are not exactly the same. Someone invented a clever hash algorithm
"Bloat" is a non-technical word. What would you have Apple remove if you could ask? Do yo want them to remove Core Image. Maybe they could loose that SQLlite thing or they could drop support for X11. I's easy to say "bloat" because it's meaning less.
It's like "government waste" yes let's get rid of that too. but then when it gets down to specifics you have to point to some guy named "John" and hand him the pink slip. When you cut waste who exactly do you fire? Same with "bloat" exactly which lines of code do you want to remove?
Microsoft is chain to their own "lock-in" model
on
Fresh Air For Windows?
·
· Score: 2, Insightful
Microsoft can't do this. Their entire business model is called "lock-in". No one buys Windows because they like it, they buy it because they need it to run the software they are invested in. If the new "Windows 7" did not run all the old software and looka dna ct just like Windows always had then people would see no reasn to buy it. Microsoft is stuck and is chained to it's own past.
The popular term "bloated" is meaning less. Who cares about software you don't use. All modern OSes (even Windows) simply leave the parts you don't actually use on the disk and they don't slow anything down. (Look up how demand paged virtual memory systems work.)
Apple did not have to create a new OS whne they switched to OS X. They bought it from Next and Next had adopted BSD Unix. So Apple was able to get a mature system that had been under continuous development from 1969. I doubt Microsoft would simply adopt Unix and thereby save a decade of work. Technically it would work but it would destroy their "lock-in" business model
"I've heard of others that have died from cancer, but nobody I personally knew, and definitely not as frequent as the successes that must be happening."
Me and my buddy were running a while back on the side walk. We'd do 10 kilometers twice a week together. He told me "This is great. If we keep doing this every week we'll likely die of cancer." He was right. Statistically if you die early it is heart disease or a stroke but if you are in good shape, exercise and eat right you can avoid that but then the second most common thing out there gets you later.
This is Japan not the US. What percent of adults in Tokyo would have a driver's license? I suspect most don't have one. Japan is also the "land of vending machines". You can't walk half a block without seeing many of them. They are everywhere, mostly facing city side walks and streets. Until not long ago they sold beer in machines. It wasn't the problem it would be in the US either because few people drive so you don't have kids driving drunk.
I'd think a better age verification system would be to use the cell phone link or bank card Many vending machines are set up to accept non-cash payments. It would be easy to check records.
My guess is this system was designed to fail. Tobacco companies have to sell to kids if they are to remain in business for long
No, you've got it wrong. The first and only goal of any government is to remain in power. If they have any other goals they are only secondary and in support of the first goal.
In a democracy there is some hope for the peole because the government tries to keep people happy so as to affect their vote.
It's easy. If you own the TLD then you have control of all the names "below it. In other words if I get.foobar then it is my DNS server that stores the.foobar data
THese photos don't reveil any secrets. The possitions or "obital elements" are published. They have to be or you have the potential of crashes and colisions. What's not publised and what's not shown in these pictures are the details of what the spacecraft do.
These things are really easy to find. You don't need a telescope. Looking that way would be hard. The better way to find them (If the orbital elements weren't published) would be to listen, not look. All of them have radio transmitters that send data to the ground.
Using radio is not a new idea. It was used on the very first satellite. When Russia launched "Sputnik" thousands of US ham radio operators would tune into the radio and used this signal to track the satellite.
Why do you say "dead"? There are more amateur radio today than there ever were. Maybe as a percent of the population the numbers are down but the total number of people holding a license is growing
I think we are actually right at the beginning of another "golden era" of amateur home building and design. With thing like Software Defined Radio (SDR) and parts like FPGAs and low cost high speed analog to digital converters a new design space has opened up.
You are correct. The bottle neck is management. Working in the aerospace field I've seen some very large software projects. I've worked on some that had 250 or more software engineers and those projects were just sub-projects of larger ones. I basically cost about a billion dollars to put up a new design spacecraft, more or less. ($1M buys about 5 engineering man years, $1B gets you 5K man years, about what it takes.) You can't run a project of that size without good project management and good system engineers and requirements management and review committees ad so on and so on. To build a big AI system you are going to have to find a way to hire managers and testers and configuration control and QA people.
No one in the AI community has the skills to pull off a large project so all of them are limited in scope to whatever the lead person can manage
"True AI" will be much more complex than building and launching a manned trip to the moon. I'm thinking on the order of hundred of thousands of engineering man years.
Yes, we all hate big organizations and paper work and red tape but just try and get 1,000 engineers allon the same path without it. Until this happens we will see even more decades of toy projects that come and go.
Back when Windows was first designed Microsoft assumed there was only one user on the computers and there was not way to get at the computer other than via the keyboard/mouse.
Unix was designed from the first to be used on a shared computer. The idea was that computers were so expensive that you could only afford one for an entire department, so you hooked up a bunch of terminals and let lots of peopleuse the machine at the same time. The "prime directive" of OS design was "it should not be possable for one user to screw up an others users work."
Unix was designed to run on very expensive shared computers while Windows was designed to run on cheap in-expensive personal computers that were owned and used by just one person. Mac OS X is based in Unix and ha very stong abillty to pertition users from each other. Untill recent years Windows did not even have to concept that there might be more then one user
Nothing special about "video". You can just ask how to keep digital data for 20 years.....
Just follow these simple rules and you will have a good change of keeping your data:
(1) The data needs to be kept on at least three different physical media (2) The data needs to be kept in at least two different geographic locations.
So by the above at a minimum you'd make write off three copies to DVD and take one of those copies to some off-site location.
But re-read the rules. Notice it says "kept" not "stored away and forgoten" that mmeans you periodically read and re-write the media. You can't expect any physical device to last 20 years. that is why you make thee copies so when one fails (not if it fails) you still have a backup. You have to KEEP thise three copys alive.
Today hard drives make good backup devices. You can buy a 500GB drive for $80. Buy four of these and rotate them to an off site location. Just take one to work with you and bring one home with you every weeks or so and re-fresh the backup. This ensures that the backups are always readable and every four or five years you replace the hard drive with whatever technology is then available.
Today 500GB hard drives give the most storage per dolar. When the 500GB drives get old maybe the 2TB drive or some Flash RAM based device will be beter.
A secondary question is what video format is best. I say it's bet to keep whatever came off the camera un-touched plus keep your finished edited shows in whatever format you are currently using. Conversion ALWAYS degrades the quality, so convert if you want but keep the camera output too.
"Where in Calif* can you find water just 2" below the surface?"
Everywhere in the entire state including the deserts. Even when the air is very dry it is never zero percent humidity. The siil 2 inches down will have some small amount of water if the air has ny at all
"I for instance, refuse to take any job that creates weapons"
The "standard" argumant against this is this: Let's say you worked in a day care center and I walked in one day and starting killing babies one after the other. You being anti-weapon would have no way to stop me. I'd just continue baby killing untill I ran out of badies then move on the the next day care center.
Next I get 50 other people and systematically rob and loot end-end retail stors and banks. We steal truck and just load them up with the goods. What would you do.
In many cases I say that weapon usage is morally required. Certainly in the bady killing scenario use of force is justified.
The people who wrote it are always complaining about there being too many lawsuits, yet they engage in the same activity that they critisize.
The above argument is not valid because the word "they" is used twice but each use of the work does not refer to the same set of people. To be valid you would need to show that the SAME PERSON is performing both actions. To do that you would have to use a proper name. The problem here is that you are judging a large group by the actions of a small subset of the group and there can be many small subsets. It's like saying "Americans are for both low taxes and higher government service. No not at all. for the most part it's poor Americans who hant bigger handouts and rich Americans who don't want to pay for handouts. Different sub-groups.
Slashdot Mirror
I think this is actually the fastest most compact way possible to encode information. It all depends on how good the compilers are. What they've done is replaces a generalized system like XML with custom written code that works only for the specific messages that are being passed. Nothing could be faster. The objection has always been that writing the custom code is hard. They have solved that issue.
No, you are only half right. An electric car not only moves the point where energy to produced from the car itself to the electric plant. But in doing so it uses to net total od far less energy. A gas powered car at most uses only 20% of the energy in the gas. the rest goes to heating air. A power plant on the other hand is much better
"Never going to happen. Nothing will ever beat the private car for convenience."
True ONLY in low-density areas. As soon as the number of people per square area goes up to some threshold cars are such a hassel that they become useless even if fuel were free. The problem is road conjestion and parking. Yes you can build huge parking lots and make more roads but this only makes the travel times longer becuase the city has to be much larger. Your typical suburb has more area devoted to cars than to buildings so EVERYTHING is spread out. If you loose all those cars then most places you need to go you can walk to.
I think the ideal design would be for dense urban areas each surrounded by open land
Technolgy can (some day) help. many in 25 years cars can drive them selves. Thenthey can travel on the road with only inches between bumbers and we don't need traffic lights as the cars can "weave" through intersections without stoping. Speeds can be very fast because the cars do not need to "react" becasue they know in advance what every other car is going to do, they comunicate.
Also you can share a car because it can drive itself to the next pick up point. like a driverless taxi. We would not need parking lots.
OK, if not in 25 years than in 100 years. I'm certain that with expensive energy and cheap computers a driverless taxi system and less space wasted with parking lots.
Solves the re-fueling problem too. The car just goes off and gets fuel itself
I had this same problem was compressed natural gas tanks. These are used for stove fuel on some sailboats.
The way to solve this problem is that you never buy a nice new battery. The cars are sold with just some random used battery the deal puts in. The car dealers just order them from the same place you'd go to swap them. You just pay a deposit once when you buy the car. Later you are charge for the "power" in the battery. If you get one that only holds 80% charge you pay for 80% of the full price.
Going with one framework simple can't work if you need to do a wide rang of work. For example I've worked on embedded microcontrollers where you have only a few kilobytes of RAM. I've worked on radar systems that used large mainframes as a processing engine and new rocket telemetry. There is no way the same tools could work on those three jobs.
But on the other hand if all you do is general office apps on a PC. Yes then standardize on a few tools
"Now it seems the majority have always thought he was guilty as Hell? Good grief!"
The majority can think different things and there be no conflict. The reason is that we have a different group of people. The set of people expressing opinion has likely changed. This is common problem with web-based surveys people are not selected at random but "self select" based on their level of interest so you end up with a very biased sample that does not refect the general population. This effect is very big here on slashdot.
If a person could wholly be inside a plane mentally (in a sense), imagine the increased control one could have,
We can do that now. If you think of the World War III Scenario, a major conflict in Europe. Piloted planes were to be flown on instruments. In europe the skies are not clear. Also with the speed of moderd planes you can't see the other plane except by instrumnets.
I worked on the B1 bommer project. One interresting feature of the plane were the aluminum panels that could fitted to the insides of the windows. Then you could not see out. This is the way the plan is designed to be flown when there are nuclear weapons being used. I suspect the B1 is not the only plane equipted with metal pannels. It is the only way to block EMP.
So now I ask what is the defference between flying inside a simulator in Kansas or in a real plan with blacked out windows except for the degree of risk to the crew. In both cases flying means punching in commands to an autopilot and reacting to various threats detected by instruments.
The days of looking through a gun site and shooting a machine gun at other airplans are long gone. It was 40 years out of date even when the first Star Wars movie was new.
most of the code out there is sequential (or nearly so) and I/O bound. So your home user checking his email, running a web browser, etc is not going to benefit much from having all that compute power. (Gamers are obviously not included in this) Thus, he predicted, processors would max out at a "relatively" low number of cores - 64 was his prediction.
Yes in 2020 if people are still doing those tasks all they would need were a "few" cores. But what if your email program actually tried t understand the text of the mail and tried to decide for you what you might be interested in? That is a HUGE and complex task that could use many, many cores per email message. Parsing the text and matching it into some kind of big semantic network is a non-trivel task. Next, what if your computer in 2020 had a web cam attached and used hand motion and lip reading as input. That alone could keep many cores bussy. Say nothing about voise input and output. And what if the company's PBX system actually answeredthe phone and talked with users and understadd simple things like "tell susan the meeting is at 2 not 3." and then the phone whould find susan and tell her.
OK my point is that if you had 1,000+ core you could do tasks you can't do now, like lip reading and answring 250 incoming calls all at once.
Ho, and what about controlling that walking robot that needs to carry your beer up the stairs? The robiot must have 1,000+ motors and sensors inside of it. One core, one thread per sonsor or motor.
we will find new tasks.
THis is simply caching the results of a search. The cache gives a 10% speed up over re-doing each search. The smart thing here is finding a way the tag or label the cache so that to searches are recognized as being the equivalent if they are not exactly the same. Someone invented a clever hash algorithm
"Bloat" is a non-technical word. What would you have Apple remove if you could ask? Do yo want them to remove Core Image. Maybe they could loose that SQLlite thing or they could drop support for X11. I's easy to say "bloat" because it's meaning less.
It's like "government waste" yes let's get rid of that too. but then when it gets down to specifics you have to point to some guy named "John" and hand him the pink slip. When you cut waste who exactly do you fire? Same with "bloat" exactly which lines of code do you want to remove?
Microsoft can't do this. Their entire business model is called "lock-in". No one buys Windows because they like it, they buy it because they need it to run the software they are invested in. If the new "Windows 7" did not run all the old software and looka dna ct just like Windows always had then people would see no reasn to buy it. Microsoft is stuck and is chained to it's own past.
The popular term "bloated" is meaning less. Who cares about software you don't use. All modern OSes (even Windows) simply leave the parts you don't actually use on the disk and they don't slow anything down. (Look up how demand paged virtual memory systems work.)
Apple did not have to create a new OS whne they switched to OS X. They bought it from Next and Next had adopted BSD Unix. So Apple was able to get a mature system that had been under continuous development from 1969. I doubt Microsoft would simply adopt Unix and thereby save a decade of work. Technically it would work but it would destroy their "lock-in" business model
"I've heard of others that have died from cancer, but nobody I personally knew, and definitely not as frequent as the successes that must be happening."
Me and my buddy were running a while back on the side walk. We'd do 10 kilometers twice a week together. He told me "This is great. If we keep doing this every week we'll likely die of cancer." He was right. Statistically if you die early it is heart disease or a stroke but if you are in good shape, exercise and eat right you can avoid that but then the second most common thing out there gets you later.
This is Japan not the US. What percent of adults in Tokyo would have a driver's license? I suspect most don't have one. Japan is also the "land of vending machines". You can't walk half a block without seeing many of them. They are everywhere, mostly facing city side walks and streets. Until not long ago they sold beer in machines. It wasn't the problem it would be in the US either because few people drive so you don't have kids driving drunk.
I'd think a better age verification system would be to use the cell phone link or bank card Many vending machines are set up to accept non-cash payments. It would be easy to check records.
My guess is this system was designed to fail. Tobacco companies have to sell to kids if they are to remain in business for long
No, you've got it wrong. The first and only goal of any government is to remain in power. If they have any other goals they are only secondary and in support of the first goal.
In a democracy there is some hope for the peole because the government tries to keep people happy so as to affect their vote.
It's easy. If you own the TLD then you have control of all the names "below it. In other words if I get .foobar then it is my DNS server that stores the .foobar data
No different then today if I owned foobar.com
I got a better idea...
Why wait until after the crime? The police should but the would-be criminal in jail before he does the crime so as to prevent it.
Hey I said "better" not good.
Why not simply buy the Mac now. Why wait and hope for two years when you can have something that just works now?
THese photos don't reveil any secrets. The possitions or "obital elements" are published. They have to be or you have the potential of crashes and colisions. What's not publised and what's not shown in these pictures are the details of what the spacecraft do.
These things are really easy to find. You don't need a telescope. Looking that way would be hard. The better way to find them (If the orbital elements weren't published) would be to listen, not look. All of them have radio transmitters that send data to the ground.
Using radio is not a new idea. It was used on the very first satellite. When Russia launched "Sputnik" thousands of US ham radio operators would tune into the radio and used this signal to track the satellite.
Why do you say "dead"? There are more amateur radio today than there ever were. Maybe as a percent of the population the numbers are down but the total number of people holding a license is growing
I think we are actually right at the beginning of another "golden era" of amateur home building and design. With thing like Software Defined Radio (SDR) and parts like FPGAs and low cost high speed analog to digital converters a new design space has opened up.
You are correct. The bottle neck is management. Working in the aerospace field I've seen some very large software projects. I've worked on some that had 250 or more software engineers and those projects were just sub-projects of larger ones. I basically cost about a billion dollars to put up a new design spacecraft, more or less. ($1M buys about 5 engineering man years, $1B gets you 5K man years, about what it takes.) You can't run a project of that size without good project management and good system engineers and requirements management and review committees ad so on and so on. To build a big AI system you are going to have to find a way to hire managers and testers and configuration control and QA people.
No one in the AI community has the skills to pull off a large project so all of them are limited in scope to whatever the lead person can manage
"True AI" will be much more complex than building and launching a manned trip to the moon. I'm thinking on the order of hundred of thousands of engineering man years.
Yes, we all hate big organizations and paper work and red tape but just try and get 1,000 engineers allon the same path without it. Until this happens we will see even more decades of toy projects that come and go.
Back when Windows was first designed Microsoft assumed there was only one user on the computers and there was not way to get at the computer other than via the keyboard/mouse.
Unix was designed from the first to be used on a shared computer. The idea was that computers were so expensive that you could only afford one for an entire department, so you hooked up a bunch of terminals and let lots of peopleuse the machine at the same time. The "prime directive" of OS design was "it should not be possable for one user to screw up an others users work."
Unix was designed to run on very expensive shared computers while Windows was designed to run on cheap in-expensive personal computers that were owned and used by just one person. Mac OS X is based in Unix and ha very stong abillty to pertition users from each other. Untill recent years Windows did not even have to concept that there might be more then one user
Nothing special about "video". You can just ask how to keep digital data for 20 years.....
Just follow these simple rules and you will have a good change of keeping your data:
(1) The data needs to be kept on at least three different physical media
(2) The data needs to be kept in at least two different geographic locations.
So by the above at a minimum you'd make write off three copies to DVD and take one of those copies to some off-site location.
But re-read the rules. Notice it says "kept" not "stored away and forgoten" that mmeans you periodically read and re-write the media. You can't expect any physical device to last 20 years. that is why you make thee copies so when one fails (not if it fails) you still have a backup. You have to KEEP thise three copys alive.
Today hard drives make good backup devices. You can buy a 500GB drive for $80. Buy four of these and rotate them to an off site location. Just take one to work with you and bring one home with you every weeks or so and re-fresh the backup. This ensures that the backups are always readable and every four or five years you replace the hard drive with whatever technology is then available.
Today 500GB hard drives give the most storage per dolar. When the 500GB drives get old maybe the 2TB drive or some Flash RAM based device will be beter.
A secondary question is what video format is best. I say it's bet to keep whatever came off the camera un-touched plus keep your finished edited shows in whatever format you are currently using. Conversion ALWAYS degrades the quality, so convert if you want but keep the camera output too.
"Where in Calif* can you find water just 2" below the surface?"
Everywhere in the entire state including the deserts. Even when the air is very dry it is never zero percent humidity. The siil 2 inches down will have some small amount of water if the air has ny at all
"I for instance, refuse to take any job that creates weapons"
The "standard" argumant against this is this: Let's say you worked in a day care center and I walked in one day and starting killing babies one after the other. You being anti-weapon would have no way to stop me. I'd just continue baby killing untill I ran out of badies then move on the the next day care center.
Next I get 50 other people and systematically rob and loot end-end retail stors and banks. We steal truck and just load them up with the goods. What would you do.
In many cases I say that weapon usage is morally required. Certainly in the bady killing scenario use of force is justified.
The people who wrote it are always complaining about there being too many lawsuits, yet they engage in the same activity that they critisize.
The above argument is not valid because the word "they" is used twice but each use of the work does not refer to the same set of people. To be valid you would need to show that the SAME PERSON is performing both actions. To do that you would have to use a proper name. The problem here is that you are judging a large group by the actions of a small subset of the group and there can be many small subsets.
It's like saying "Americans are for both low taxes and higher government service. No not at all. for the most part it's poor Americans who hant bigger handouts and rich Americans who don't want to pay for handouts. Different sub-groups.