Re:Swap nessisary in low mem (128M) systems
on
Is Swap Necessary?
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· Score: 1
You're rediculous to be trying to use firefox on a machine with 128Mb of RAM and no physical disk swap.
i'd not say that, if it weren't for the fact that CF media only has so many writes before it starts to die, and it's waaaay too expensive to use for such purposes. It depends on the manufacturer, but it's certainly not enough writes to use for swap consistently.
Kernel compiles do -not- tax the system. They utilize it. There are relatively few process threads used during a kernel build, substantial CPU use per process, a fair amount of disk reading, and a large amount of memory swapping about and modification.
Its perfectly reasonable to expect a system to be responsive while compiling a large project. That's not a "taxed" system. A slashdotted machine, which spawns thousands of apache processes, is taxed, however.
Except for your statement that for "anything less than 512M or 1G of RAM you want to have some swap"... You want to have swap all the time, unless there's a power-related (ie, laptop) reason to not have it. As the article says, it's trivially demonstrated that there is a performance increase by using swap, regardless of how much RAM. It is, however, imperative to have swap if the machine doesn't have much ram, otherwise you'll run into some nasty results after a while.:)
This product will not even have the chance to die. It'll never even live, I'd suspect.
Only chance it has is in a scenario that has absolutely no need for backward compatibility with old document formats, and does not interface with anyone outside the company. Why? The damned thing only has a single file format that's supported -.eio.
So basically, there's a market for 4, maybe 5 copies of EI Office.
I think the founding fathers intended for us to form armed rebellion if the federal government ever got out of hand in such a fashion.
also seems that the federal government made that fundamentally impossible when they did things like instigate a standing military and various other actions around the civil war...
Dear god that had to be the worst star trek episode, EVER. The entire episode was mostly drivel, with some of the worst choreography I've seen - worse than much of what's on shows like Andromeda even, which says a lot. Then, during the last segment of the show, they totally whack the plot, with absolutely no precidence. What's that? Yeah, we're going to make them have warped back to 1942 - or possibly an alternate dimension. The Nazis are apparently ruled by aliens, and Archer somehow didn't die in the blast. Etc. They could have at least spent the second half of the episode building up to it. Nothing like a completely pointless cliff-hanger to make a person not care anymore.
I think about how much I've learned from various games, and it makes me feel sorry for people without comptuters.
For instance: Lords of the Realm III has a bunch of battle re-enactment scenarios, complete with the history of the event. Being a geek, I read those histories... I now know a fair bit about the warfare of Britian ~1400s.
DeusEx, while not in the least bit historical, taught me a lot about conspiracy theories.:P Some might not find that helpful, but I do, as history or civics from the textbooks never gives you a full picture of how things really are - just the governmentally sponsored version. The game also provided a look into a "political worldview" where the government isn't to be trusted, in essence - something I don't doubt most students could benefit from.
I don't doubt that my most fundamental understanding of international negotiations comes from the Civ games, to some degree. Sure, it's matured, but I was playing the the original civ long before I was really aware that the US wasn't the central point of the world.
Now that I think about it, the Carmen SanDiego games helped me learn research skills fairly well. I didn't particularly enjoy the game, but I did enjoy following the trail and looking stuff up to try and get to the next point. The interesting thing is (from what I recall!) the game wasn't primarily sold to schools, but had a fairly large commercial offering as well...
You'd think that slashdot editors would get tired, or even a little embarassed, of posting things a full day behind the single guy (I think) that maintains fark.com.
I'd wager at least 2/3rds of the really interesting stuff that I come across on slashdot has been on fark for half a day or more... sad.
Anyone remember when slashdot would link to nifty project sites, nifty home-brew stuff and the like? Is it that such things aren't undertaken as much anymore, they're harder to find due to all the other garbage, or slashdot just doesn't go after the fun stuff? What am I missing here?
An office I work for has shitty HP consumer products. "Officejet" and the like. One, running the latest Win2k packs, crashes regularly with a BSOD. Latest drivers, and what have you. It was worse with older software.
I've seen it with other things as well. Had one system freeze when trying to use USB memory sticks (WinXP)...
I've not heard anyone advocate linux in such a fashion since around 2001, when Win2k started to gain acceptance (ie, when ME stopped being sold, gamers decided it really was better than win98).
Now? Now we use the oh-so-far-fetched arguement that linux doesn't suffer from the slew of worms, viruses, popups, and other such plauge-like "features" of Windows. You'd certainly be right that the effect of this is that it drives a wedge between Linux users and potential converts - it pisses those Windows users off to no end that we're able to shrug off these hindrances to a large degree. Sure, we have to deal with fixing everyone else's infections, etc., but feigning ignorance is often helpful in dealing with the stress of dozens of people asking you for help a day, for several days, roughly once a month and a half.
I've got a half-completed VW Beetle original in my garage with a Porsche 900 turbo engine in it.
I've had some difficulty finishing it, though. It keeps crashing due to the large amount of acceleration, as it appears the VW's suspension isn't built for such speeds.
I had a silly asignment for a class of mine: look up and a router, tell me what it can do, and then compare/contrast the router you picked with one another classmate picked.
Being the sadistic mothrefucker that I am, I hopped over to cisco's site at about 1am and saw this beast listed "Carrier Router System". I didn't recognize it as a "normal" Cisco offering, and 92Tb/s is really fucking fast. Though, beyond that, I didn't think anything of it. Cisco is just expected to have the fastest stuff out there, right? And to think, were I more up on my Cisco products, I could've submitted this to the front page. (And they could have denied me access, and posted someone else's submission 12 hours later, as tends to be the case around here:P)
As it sands, those sorry sons-of-bitches in my IT200 networking course are going to hate me. They likely all picked SOHO equipment to compare/contrast and won't know up from down when it comes to comparing/contrasting. "What's 'Tbps' mean?" they'll ask.
Did you bother to even look at the site? Nooo of course not. From the site:
The Cisco CRS-1 is powered by Cisco IOS XR Software, a unique self-healing and self-defending operating system designed for always-on operation while scaling system capacity up to 92 Tbps.
Click on "Cisco IOS XR" and you get:
Q. What is Cisco IOS XR Software?
A. Cisco IOS XR Software is the newest member of the Cisco IOS Software Family. Cisco IOS XR has been developed to address the requirements for scale, availability, and service flexibility which arise from the creation of converged packet infrastructures that consolidate voice, video, and data services. Cisco IOS XR Software has been specifically optimized to take advantage of the massively distributed processing capabilities of the Cisco CRS-1 Carrier Routing System.
Why do you even bother posting? I wouldn't think it's for karma whoring - such a low UID isn't likely to partake in such things unless adicted. It certainly isn't to contribute quality material to the discussion, either.
3. The third folk belief is that random passwords are better than those based on mnemonic phrases. However, each appeared to be just as strong as the other. So this belief is debunked.
Its always confounded me as to why people have insisted on this folk belief. I, for one, have always insisted that mnemonic phrases are no less secure than random numbers. (Likewise for the memorability vs. single-phrase passwords.) I'm glad there's finally some proof so that I can get people to use sane passwords (neither easy to guess, nor difficult to remember).
They're trying to make "XNA as universal as DVD". That means mass marketing. Mass marketing means there's not going to be a large percentage of gamers interested in rich titles such as role playing (FF) stuff has the potential to present. It means you're likely to see a lot more Madden games, and a lot more stupid, repetitive games that are like 007, where two people can play head-to-head if there's a second controller.
What MS is envisioning here is the death of quality gaming (as if its not already in its last days of life as it is). We're talking about the "Scary Movie 3" or "Jurassic Park 3" of gaming. I recall something similar during the later years of the NES, when there was a very low cost of entry into the market (cartridges were relatively cheap), and there was a very high saturation of NES systems in homes.
Microsoft is essentially bored with the current obsession surrounding console cycles, and the obsolescence that happens every five years.
This means one of two things to me: either MS doesn't understand the market which is composed of hardcore gamers (ie, people that like gaming largely because of this so-called obsolescence, and the perpetual upgrades in graphic quality that it causes), or these hard-core gamers are no longer a significant part of the gaming market.
Given the rash of titles I've seen over the last couple of years which are lackluster at best (stuff like "Viking Invasion" or most of the other game that fills the shelves at Best Buy), I'd personally bet my money on there being a fairly large departure of the game companies from focusing on people that enjoy games and live them, to marketing (and thus creating for) the average consumer.
In essence: gaming is dead, folks. Don't expect to see the cycle of new, fun games continue. They haven't continued for some time now.
The high school my siblings graduated from only offered one history class, and it was an optional class only available to seniors.
How is that too much history?
If anything, schools are not teaching enough anything. They're simply going through the motions of 'education'. You're absolutely right in what schools should be teaching, though.
It's not a stereotype, it's a statistical reality. A large portion of Americans believe it.
So you're saying that because it's a statistical reality, it's not a stereotype? Does the fact that it's a 'statistical reality' mean that it's truth that all Christians are "loudmouth conservative wackos who perpetuate the stereotype that the world is four thousand years old"?
In that case, since it is a "statistical reality" that black kids do poorly in school, it must be true that black kids are all less intelligent.
This is why sane people haven't used glibc for quite some time. Just search for glibc on an installed debian (or, I think gentoo) system. You won't (shouldn't!) find it.
well, being american, i can outline what makes it necessary to own a car, and why, for the most part. granted, there are regions of the US where a person can get by with a bike, public transportation, or such - at least for the majority of their weekly travels (say, in some of the smaller northeastern towns - provided they live in that town - or in the metro areas - provided they haven't too far to travel/don't mind traveling on the inefficient and expensive public transit).
1) it's not uncommon for it to be quite a few miles between anywhere you need to get throughout the day. For instance, I live in a midwestern US "metro area" fo 200,000 people - the core city itself is roughly 150,000, I'd wager. Not too big, no, but it's about 3 miles to the nearest grocery store (and we're relatively close!), 7 miles or so to my college, and all paths are heavily conjested with traffic, with no safe areas to use a bike. In larger towns or suburbs, it's often quite a few miles simply to the edge of a "housing subdivision" - you can notice this if you take a flight over the midwest. 2) Public transit is horrible. it essentially doesn't exist, as there are a scant number of stops, and they're not made very frequently (1+ hours, never on time). It'll take twice as long to get where you're going via bus as via car, usually in quite an around-about fashion. Furthermore, they're very expensive for what they are, and only the people that are unable to drive seem to take them, making them a very uncomfortable place (mentally handicapped, drunks, etc.), as these people often get city-sponsored passes. 3) Automobiles are fairly insanely priced for leasing or purchase. It's quite cheap - it makes a lot more sense to pay $100/month for car payments to a rich person than to pay $40/month for the bus. Likewise for people using used/older cars - $20/40 a month for their older car, vs $40 for the inconvenience of a bus? 4) It's a chicken/egg problem for public transit. People won't ride the transit because it's not there/it sucks. The transportation isn't put into place because people won't use it/they alraedy have 30,000$ cars. 5) many, many people don't live "in town", and thus it's a transit just to get to town. When I lived in Virginia, it was a good 20 minute drive to town, which had to be made multiple times daily. 6) Weather does not permit for biking or even public transit throughout the year in many parts of the country. It gets too cold, and is completely hostile to anyone outdoors. It gets to be -30F here in the winters regularly. My car will often have troubles traversing the roads, and it's a 6 cylinder Ford Taurus - a fairly 'average' sized car. 7) Our infrastructure was designed with the automobile in mind. Thus, nearly everything is miles appart, and towns are zoned in square yard segments that are thousands by thousands of feet. Everything is made into little "centers" - the center of town, the business district, etc.
Europeans often get off on dissing Americans for driving everywhere. This is pretty rediculous, as our medium sized states are larger than many European countries. I suspect that this stems largely from ignorance - they think the world is a lot smaller than it is. It takes days to drive across our country, driving over speed limit, even if you don't stop to sleep (rotating drivers). This size makes it so that if you don't drive, you're basically going to be a hillbilly, as you won't be able to go anywhere if you don't drive. It's not so easy to bike across a county here, as they're many, many miles across with few towns - let alone towns with stores in many states. We don't have the benefit of the nicely organic european cities, with stores and housing within a block of each other, consistently (so I hear).
There's more stuff, but I'm hoping you get a general idea...
if you're implimenting this stuff, you need to either know it like the palm of your own hand, because you will be the one that will be called when there are problems.
from the tone of your 'ask slashdot' this isn't the case.
You don't need to train everyone. You just need to train the people at the door. I believe Best Buy has practices which might be similar to what is necessary to deter such behavior, but I could be mistaken.
Slashdot Mirror
You're rediculous to be trying to use firefox on a machine with 128Mb of RAM and no physical disk swap.
i'd not say that, if it weren't for the fact that CF media only has so many writes before it starts to die, and it's waaaay too expensive to use for such purposes. It depends on the manufacturer, but it's certainly not enough writes to use for swap consistently.
Plus, CF is slow.
Kernel compiles do -not- tax the system. They utilize it. There are relatively few process threads used during a kernel build, substantial CPU use per process, a fair amount of disk reading, and a large amount of memory swapping about and modification.
:)
:)
Its perfectly reasonable to expect a system to be responsive while compiling a large project. That's not a "taxed" system. A slashdotted machine, which spawns thousands of apache processes, is taxed, however.
Except for your statement that for "anything less than 512M or 1G of RAM you want to have some swap"... You want to have swap all the time, unless there's a power-related (ie, laptop) reason to not have it. As the article says, it's trivially demonstrated that there is a performance increase by using swap, regardless of how much RAM. It is, however, imperative to have swap if the machine doesn't have much ram, otherwise you'll run into some nasty results after a while.
I'd agree with your last two sentiments.
This product will not even have the chance to die. It'll never even live, I'd suspect.
.eio.
Only chance it has is in a scenario that has absolutely no need for backward compatibility with old document formats, and does not interface with anyone outside the company. Why? The damned thing only has a single file format that's supported -
So basically, there's a market for 4, maybe 5 copies of EI Office.
I think the founding fathers intended for us to form armed rebellion if the federal government ever got out of hand in such a fashion.
also seems that the federal government made that fundamentally impossible when they did things like instigate a standing military and various other actions around the civil war...
Dear god that had to be the worst star trek episode, EVER. The entire episode was mostly drivel, with some of the worst choreography I've seen - worse than much of what's on shows like Andromeda even, which says a lot. Then, during the last segment of the show, they totally whack the plot, with absolutely no precidence. What's that? Yeah, we're going to make them have warped back to 1942 - or possibly an alternate dimension. The Nazis are apparently ruled by aliens, and Archer somehow didn't die in the blast. Etc. They could have at least spent the second half of the episode building up to it. Nothing like a completely pointless cliff-hanger to make a person not care anymore.
I think about how much I've learned from various games, and it makes me feel sorry for people without comptuters.
:P Some might not find that helpful, but I do, as history or civics from the textbooks never gives you a full picture of how things really are - just the governmentally sponsored version. The game also provided a look into a "political worldview" where the government isn't to be trusted, in essence - something I don't doubt most students could benefit from.
For instance: Lords of the Realm III has a bunch of battle re-enactment scenarios, complete with the history of the event. Being a geek, I read those histories... I now know a fair bit about the warfare of Britian ~1400s.
DeusEx, while not in the least bit historical, taught me a lot about conspiracy theories.
I don't doubt that my most fundamental understanding of international negotiations comes from the Civ games, to some degree. Sure, it's matured, but I was playing the the original civ long before I was really aware that the US wasn't the central point of the world.
Now that I think about it, the Carmen SanDiego games helped me learn research skills fairly well. I didn't particularly enjoy the game, but I did enjoy following the trail and looking stuff up to try and get to the next point. The interesting thing is (from what I recall!) the game wasn't primarily sold to schools, but had a fairly large commercial offering as well...
You'd think that slashdot editors would get tired, or even a little embarassed, of posting things a full day behind the single guy (I think) that maintains fark.com.
I'd wager at least 2/3rds of the really interesting stuff that I come across on slashdot has been on fark for half a day or more... sad.
Anyone remember when slashdot would link to nifty project sites, nifty home-brew stuff and the like? Is it that such things aren't undertaken as much anymore, they're harder to find due to all the other garbage, or slashdot just doesn't go after the fun stuff? What am I missing here?
apparently such things have been done for a long time by the US government in some capacity.
Ditto. Not the same problem for me, but:
An office I work for has shitty HP consumer products. "Officejet" and the like. One, running the latest Win2k packs, crashes regularly with a BSOD. Latest drivers, and what have you. It was worse with older software.
I've seen it with other things as well. Had one system freeze when trying to use USB memory sticks (WinXP)...
I've not heard anyone advocate linux in such a fashion since around 2001, when Win2k started to gain acceptance (ie, when ME stopped being sold, gamers decided it really was better than win98).
Now? Now we use the oh-so-far-fetched arguement that linux doesn't suffer from the slew of worms, viruses, popups, and other such plauge-like "features" of Windows. You'd certainly be right that the effect of this is that it drives a wedge between Linux users and potential converts - it pisses those Windows users off to no end that we're able to shrug off these hindrances to a large degree. Sure, we have to deal with fixing everyone else's infections, etc., but feigning ignorance is often helpful in dealing with the stress of dozens of people asking you for help a day, for several days, roughly once a month and a half.
I've got a half-completed VW Beetle original in my garage with a Porsche 900 turbo engine in it.
I've had some difficulty finishing it, though. It keeps crashing due to the large amount of acceleration, as it appears the VW's suspension isn't built for such speeds.
I had a silly asignment for a class of mine: look up and a router, tell me what it can do, and then compare/contrast the router you picked with one another classmate picked.
:P)
Being the sadistic mothrefucker that I am, I hopped over to cisco's site at about 1am and saw this beast listed "Carrier Router System". I didn't recognize it as a "normal" Cisco offering, and 92Tb/s is really fucking fast. Though, beyond that, I didn't think anything of it. Cisco is just expected to have the fastest stuff out there, right? And to think, were I more up on my Cisco products, I could've submitted this to the front page. (And they could have denied me access, and posted someone else's submission 12 hours later, as tends to be the case around here
As it sands, those sorry sons-of-bitches in my IT200 networking course are going to hate me. They likely all picked SOHO equipment to compare/contrast and won't know up from down when it comes to comparing/contrasting. "What's 'Tbps' mean?" they'll ask.
Did you bother to even look at the site? Nooo of course not. From the site:
The Cisco CRS-1 is powered by Cisco IOS XR Software, a unique self-healing and self-defending operating system designed for always-on operation while scaling system capacity up to 92 Tbps.
Click on "Cisco IOS XR" and you get:
Q. What is Cisco IOS XR Software?
A. Cisco IOS XR Software is the newest member of the Cisco IOS Software Family. Cisco IOS XR has been developed to address the requirements for scale, availability, and service flexibility which arise from the creation of converged packet infrastructures that consolidate voice, video, and data services. Cisco IOS XR Software has been specifically optimized to take advantage of the massively distributed processing capabilities of the Cisco CRS-1 Carrier Routing System.
Why do you even bother posting? I wouldn't think it's for karma whoring - such a low UID isn't likely to partake in such things unless adicted. It certainly isn't to contribute quality material to the discussion, either.
3. The third folk belief is that random passwords are better than those based on mnemonic phrases. However, each appeared to be just as strong as the other. So this belief is debunked.
Its always confounded me as to why people have insisted on this folk belief. I, for one, have always insisted that mnemonic phrases are no less secure than random numbers. (Likewise for the memorability vs. single-phrase passwords.) I'm glad there's finally some proof so that I can get people to use sane passwords (neither easy to guess, nor difficult to remember).
most technical problems I've experienced with users tends to be layer 8 of the OSI model...
You completely miss what MS is trying to do.
They're trying to make "XNA as universal as DVD". That means mass marketing. Mass marketing means there's not going to be a large percentage of gamers interested in rich titles such as role playing (FF) stuff has the potential to present. It means you're likely to see a lot more Madden games, and a lot more stupid, repetitive games that are like 007, where two people can play head-to-head if there's a second controller.
What MS is envisioning here is the death of quality gaming (as if its not already in its last days of life as it is). We're talking about the "Scary Movie 3" or "Jurassic Park 3" of gaming. I recall something similar during the later years of the NES, when there was a very low cost of entry into the market (cartridges were relatively cheap), and there was a very high saturation of NES systems in homes.
Microsoft is essentially bored with the current obsession surrounding console cycles, and the obsolescence that happens every five years.
This means one of two things to me: either MS doesn't understand the market which is composed of hardcore gamers (ie, people that like gaming largely because of this so-called obsolescence, and the perpetual upgrades in graphic quality that it causes), or these hard-core gamers are no longer a significant part of the gaming market.
Given the rash of titles I've seen over the last couple of years which are lackluster at best (stuff like "Viking Invasion" or most of the other game that fills the shelves at Best Buy), I'd personally bet my money on there being a fairly large departure of the game companies from focusing on people that enjoy games and live them, to marketing (and thus creating for) the average consumer.
In essence: gaming is dead, folks. Don't expect to see the cycle of new, fun games continue. They haven't continued for some time now.
Too much about the past, are you kidding me?
The high school my siblings graduated from only offered one history class, and it was an optional class only available to seniors.
How is that too much history?
If anything, schools are not teaching enough anything. They're simply going through the motions of 'education'. You're absolutely right in what schools should be teaching, though.
It's not a stereotype, it's a statistical reality. A large portion of Americans believe it.
So you're saying that because it's a statistical reality, it's not a stereotype? Does the fact that it's a 'statistical reality' mean that it's truth that all Christians are "loudmouth conservative wackos who perpetuate the stereotype that the world is four thousand years old"?
In that case, since it is a "statistical reality" that black kids do poorly in school, it must be true that black kids are all less intelligent.
I do hope you catch my sarcasm.
This is why sane people haven't used glibc for quite some time. Just search for glibc on an installed debian (or, I think gentoo) system. You won't (shouldn't!) find it.
Two direct links on the front page of slashdot to (literally) stollen IP?
I wonder if Slashdot will get in trouble with Cisco for this? The moderators could have at least have checked the links, no?
But if banality isn't allowed, why does slashdot even exist? I thought that was the point. :P
well, being american, i can outline what makes it necessary to own a car, and why, for the most part. granted, there are regions of the US where a person can get by with a bike, public transportation, or such - at least for the majority of their weekly travels (say, in some of the smaller northeastern towns - provided they live in that town - or in the metro areas - provided they haven't too far to travel/don't mind traveling on the inefficient and expensive public transit).
.
1) it's not uncommon for it to be quite a few miles between anywhere you need to get throughout the day. For instance, I live in a midwestern US "metro area" fo 200,000 people - the core city itself is roughly 150,000, I'd wager. Not too big, no, but it's about 3 miles to the nearest grocery store (and we're relatively close!), 7 miles or so to my college, and all paths are heavily conjested with traffic, with no safe areas to use a bike. In larger towns or suburbs, it's often quite a few miles simply to the edge of a "housing subdivision" - you can notice this if you take a flight over the midwest.
2) Public transit is horrible. it essentially doesn't exist, as there are a scant number of stops, and they're not made very frequently (1+ hours, never on time). It'll take twice as long to get where you're going via bus as via car, usually in quite an around-about fashion. Furthermore, they're very expensive for what they are, and only the people that are unable to drive seem to take them, making them a very uncomfortable place (mentally handicapped, drunks, etc.), as these people often get city-sponsored passes.
3) Automobiles are fairly insanely priced for leasing or purchase. It's quite cheap - it makes a lot more sense to pay $100/month for car payments to a rich person than to pay $40/month for the bus. Likewise for people using used/older cars - $20/40 a month for their older car, vs $40 for the inconvenience of a bus?
4) It's a chicken/egg problem for public transit. People won't ride the transit because it's not there/it sucks. The transportation isn't put into place because people won't use it/they alraedy have 30,000$ cars.
5) many, many people don't live "in town", and thus it's a transit just to get to town. When I lived in Virginia, it was a good 20 minute drive to town, which had to be made multiple times daily
6) Weather does not permit for biking or even public transit throughout the year in many parts of the country. It gets too cold, and is completely hostile to anyone outdoors. It gets to be -30F here in the winters regularly. My car will often have troubles traversing the roads, and it's a 6 cylinder Ford Taurus - a fairly 'average' sized car.
7) Our infrastructure was designed with the automobile in mind. Thus, nearly everything is miles appart, and towns are zoned in square yard segments that are thousands by thousands of feet. Everything is made into little "centers" - the center of town, the business district, etc.
Europeans often get off on dissing Americans for driving everywhere. This is pretty rediculous, as our medium sized states are larger than many European countries. I suspect that this stems largely from ignorance - they think the world is a lot smaller than it is. It takes days to drive across our country, driving over speed limit, even if you don't stop to sleep (rotating drivers). This size makes it so that if you don't drive, you're basically going to be a hillbilly, as you won't be able to go anywhere if you don't drive. It's not so easy to bike across a county here, as they're many, many miles across with few towns - let alone towns with stores in many states. We don't have the benefit of the nicely organic european cities, with stores and housing within a block of each other, consistently (so I hear).
There's more stuff, but I'm hoping you get a general idea...
if you're implimenting this stuff, you need to either know it like the palm of your own hand, because you will be the one that will be called when there are problems.
from the tone of your 'ask slashdot' this isn't the case.
You don't need to train everyone. You just need to train the people at the door. I believe Best Buy has practices which might be similar to what is necessary to deter such behavior, but I could be mistaken.