... I could see how it'd be easy for a malicious user to force a huge number of updates by manipulating their files to force a re-patch operation, quickly taking up an ungodly amount of disk space on the server.
Ungodly? The size of the patch depends on the size of the binary diff. If the patches are very large then maybe direct download would be easier then using a differential patch system. Also, it would be quite trivial to stop an attack like this.
A strong cryptographic hash like SHA-1 would be necessary.
I don't think you really understand the rsync algorithm. Andrew Tridgell has an excellent discussion on signature size in section 4.1 of his PhD thesis. You should estimate the correct size for yourself since it depends on the size of your files. BTW, Tridgell asserts that 32 bits of strength is enough for files up to 64GB in size.
Patching between multiple version steps would probably make more sense, but it'd be better to adapt the algorithm to patch several times in a row instead.
I thought I mentioned this in my original post. A single pass is sometimes sufficient but not always. You must be ready to handle multiple passes.
There are two sides to a market, supply and demand. As you have conclusively pointed out demand for MMO games is still rising. However, supply is rising also. Unfortunately there are no hard numbers on supply since game development is so secretive. However, I think most industry insiders would agree that the supply of MMO games is growing much faster than it should be. This discrepancy between growth of supply and growth of demand is causing the observed market saturation despite rising consumer interest in MMO games.
Something that might be useful to try out is a patch method I developed for a MMORPG. The problem is a challenge since MMOs are constantly updating game files. Also, many of the files are very large art resources which might only change a small percentage from patch to patch. On top of this, players are always mesing with their files so you can't assume that any file is in any known state on the basis of some "patch level".
The method I came up with was to use essentially the rsync algorithm, but I reversed it so that the computationally expensive parts were performed on the client side. The results of each computation were stored on the server side as a "patch" so that the computation was performed only once. This provided a patch system that was dynamic but without generating large server load.
The advantages are:
1. Patches are generated dynamically so the files can be in any state (truncated, too big, filled with garbage, missing enitirely, etc).
2. The heavy computation is performed on the client side so that patch generation does not drive up server load.
3. Computed patches are stored and reused, so a database of patches it quickly built up.
4. Patches are efficient (based on binary diff).
A detailed example follows; knowledge of rsync is required for understanding.
For example, let's suppose you are releasing a new content upgrade. A particular file's signature has changed from F4A3 to 26B1. (For brevity I am using a 16-bit signature, in practice it is much much larger.) When the first client connects to the patch server it receives the updated list of file signatures. The client notices that the file is now old so it requests a patch for F4A3->26B1. The patch does not exist yet, so the reverse-rsync algorithm activates and the client calculates the F4A3->26B1 patch. When that patch has been generated it is returned to the patch server and all future clients can just download the patch and skip the reverse-rsync. After applying a patch, the result is checked to make sure that you actually ended up with 26B1. If you did not, extra rounds of patching are performed.
Some Notes: These extra rounds are consequences of rsync and a security check as well to prevent bad patches from being uploaded to the server. And, normally the release maintainer would "pre-seed" the patch server by patching a clean current version to the new version just before release.
My encumberance numbers may not be accurate for you. It depends a lot on where the company is located and what kind of people you are hiring. I hope I haven't misled you.
You seem dedicated, I suggest you get on the MUD-Dev mailing list and ask Andrew Tepper for advice. He is lead on A Tale in the Desert. ATITD is a small-scale MMORPG on par with your target of 1500 subscribers (they have over 2000 I believe). When I last kept track of ATITD they had about 5 people working on the project. Andrew Tepper could probably give you a lot of useful feedback on the business aspects of your idea.
A smaller, more focused MMORPG, perhaps even the "massive" part needs to be removed. Target subscription is 500-1500 subscribers, with a set upper limit of probably 1500. Target subscription fee $50 a month (read on before you just dismiss everything outright).
...
Anyone care to comment on how stupid all of this is?
1500 people at $50 per month = $900,000 annual revenue.
Let's assume cost of revenue is only 50% (very generous!) so that leaves us with $450,000 gross profit.
Let's assume a total encumberance of $160,000 per employee (realistic). That gives us enough for 2.8 employees, not including you. That, of course, would be for zero net income.
Not much of a company, eh?
(Encumberance means all costs associated with an employee: ie. salary, taxes, healthcare, office space, electricity, etc. Think of it as TCO for people. It can get as high as $220,000 in large companies.)
4. RPOW uses hashcash for its proof of work (POW) tokens. Hashcash tokens are evidence that a certain substantial amount of computer effort was expended to create them. RPOW allows hashcash tokens to be exchanged for RPOW tokens of an equivalent value, which can then be further exchanged for new RPOW tokens. The effect is similar to being able to pass hashcash tokens from hand to hand while they retained their value, as if they were real physical objects that had an inherent rarity.
Some people have proposed an anti-spam system where spammers need to generate RPOW tokens, but ordinary users can exchange them. Is there anything in the system to prevent copying an RPOW token? If a spammer receives a single good token, couldn't he just make a million copies of that token and send one of each token to each spam recipient? Without collaboration each individual receiver cannot know that it is receiving a duplicated token.
Firstly, I think it is unreasonable to expect mail servers to collaborate to look for duplicated tokens. And secondly, I think that any digital token can be duplicated regardless of any hardware or software copy protection.
Just because an airline is a private corporation rather than a goverment agency doesn't mean that they can violate your fourth amendment rights.
A classic example, and one Slashdotters are likely to be familiar with, is the bag checkers at Fry's. They have no right to search your personal effects without cause, and that includes a Fry's bag. Since you just came away from the register with that bag, they have no justification to search it.
I always ignore them, and they have never tried to search me forcibly. They know that they have no right to do so. They can only search you if you meekly allow yourself to be searched.
Actually, I have no problem with seeing a self-taught doctor. I call her Mom. She would prescribe me chicken soup, orange juice, bed rest, etc for common colds and other minor illnesses. If the illness was serious I would, of course, go to a specialist, an M.D.
Similarly, self-taught programmers are good enough for the bulk of programs. Let's face it, programming is actaully quite easy. You don't need a crack team of ivy league computer scientists to organize your MP3 collection anymore than you need to go to the hospital every time you get a little sniffle.
There was a furor that surrounded the nuetrino when it was first thought up and they did think that it was so weakly interacting that they'd never find it. (...we found it)
The Higgs boson is another case in point; (...). Do we write off the Higgs boson because we don't have a detector for it?
Oh, please. You bring up a single example of a hard to find particle that was eventually detected, and use that to support the existence of the Higgs boson? That's not science, it's religion. The existence or non-existence of the Higgs boson will be determined experimentally, not by theory.
The history of physics is full of theorized particles or fields that never panned out. We just never read about them in textbooks, because who wants to learn things that are wrong. We tell glamorous annecdotes about the hard to find particles that were discovered (e.g. Neutrino) and ignore the theories that were failures (e.g. Ether). So, our perceptions are colored, and we over-value theory.
Please don't fall into that trap. Look at things objectively and critically. No matter how good the theory looks, experimental confirmation is necessary. Physicists believed in the existence of Ether right up until the 1887 Michelson-Morley experiment.
PS. I wanted to provide links to more examples than just Ether, but for the exact reasons I outlined above I had diffculty locating web pages on other failures.
Suppose a grocery store is selling two brands of soft drink that taste the same. Pep sells in a 6 pack for $6, and Coca sells only a gross (144 cans) for $144. They are the same price per can, but which one do you think will sell better?
But, this analogy is no good because soft drinks have weight and volume, but stock has neither!
Okay, so replace the soft drink cans with a credit card. You can take the credit card to any restaurant and redeem it for a can of Pep or Coca. Now weight and volume don't matter. Do Pep and Coca sell equally now? No. Pep still sells better, because nobody wants to shell out $144 just to get a drink.
Stock price doesn't matter as far as the financial value of stock, but it does matter for the convenience of buying and selling stock. Therefore most companies split and reverse-split to keep their stock price in a nominal range. And they are correct to do so.
But people who use google's search engine just to find stuff are
not customers...they're the product.
Very insightful. However, I offer a slightly different viewpoint. People who use google's search engine are customers. They buy search results and pay with their eyeballs.
Isn't economics great? So many ways to view the same activity.
PS. Will a real economist please step in and let us know which viewpoint is correct?
2. Computers infected with the worm spam random addresses.
3. Sit back and enjoy the chaos.
Or, even better: If authentication is weak, then have the worm email you and collect the bonds.
I read the article and they basically say that this is possible. Their defense is that you can only lose at most the (small) amount that you keep in your ABM account. However, when your account is depleted what happens next? You can't send email anymore? How do you get your money back? Some kind of insurance claims type procedure? No thanks.
Q. Why does the game industry { advertise hours of gameplay | not innovate | sell the same game over and over | only make games for males | advertise polygon counts | only make violent games }?
Bacteria sems to be a common thread here. Specifically whether they can live on Mars or not. For those who want to find more information on bacteria living under extremely adverse conditions, they are referred to in scientific literature as extremophiles
apollo trip = 6500 kg (the 2500 kg mentioned is extraneous right?)
proposed laser = 1 KW
150 proposed lasers = 150 KW * 1 kg / 1 MW = 150 g
units needed for apollo trip = 6500 kg / 150 KW * 1 MW / 1 kg = 43,333 units (what is a unit anyway? a set of 150 lasers or a single laser? whatever, 6.5 million lasers are needed)
12 GW = ? (huh? I thought it was 1 MW/kg, so who cares how many lasers or units are used it's going to be 6.5 GW)
Can you repost with the math again? I must be missing a conversion somewhere, or there is a typo. Thanks.
The life as an engineer was (excuse me) pathetic. Why should I spend all my life chained to a desk, living in a cube farm, and putting up with the Boss from Hell who figured he owned me as so much chattel property? Life is much better now.
My life as an engineer is fantastic. I love staying indoors at a desk and exercising my mind. I don't have to suck up to my boss because my industry is a meritocracy. I enjoy the freedom that comes from being able to switch jobs anytime because good people are always in demand. Life couldn't be better.
I am happy that you have finally found your calling in life. But, don't put down my industry. Leave those teenagers alone; let them find their own way. They just might enjoy engineering. I know I do.
This is going to get modded down as flamebait, but it has to be said.
To all the whiners saying it can't be done:
We already have something called DNS. What exactly do you think DNS does? It translates from a portable network address to a hierarchically structured IP address.
To the guys who want to own their IP address:
Suck on it. Get a domain name, that's what DNS was invented for.
I'm currently 17, employed by a euro internet exchange(I'm in the US), making ~$1800/mo, with huge room to grow. I didn't get this job under any false pretenses-- no lying or denying, I even brought it up. I'm sure income wise I'm far from the top of slashdot, but I'd say I'm doing pretty well off.
Slashdot Mirror
bmail
cmail
dmail (taken)
email (taken)
gmail (taken)
pmail
tmail
vmail
zmail
So the robot consumes flies for power ... what do Buddhists think about this?
There are two sides to a market, supply and demand. As you have conclusively pointed out demand for MMO games is still rising. However, supply is rising also. Unfortunately there are no hard numbers on supply since game development is so secretive. However, I think most industry insiders would agree that the supply of MMO games is growing much faster than it should be. This discrepancy between growth of supply and growth of demand is causing the observed market saturation despite rising consumer interest in MMO games.
The method I came up with was to use essentially the rsync algorithm, but I reversed it so that the computationally expensive parts were performed on the client side. The results of each computation were stored on the server side as a "patch" so that the computation was performed only once. This provided a patch system that was dynamic but without generating large server load.
The advantages are:
1. Patches are generated dynamically so the files can be in any state (truncated, too big, filled with garbage, missing enitirely, etc).
2. The heavy computation is performed on the client side so that patch generation does not drive up server load.
3. Computed patches are stored and reused, so a database of patches it quickly built up.
4. Patches are efficient (based on binary diff).
A detailed example follows; knowledge of rsync is required for understanding.
For example, let's suppose you are releasing a new content upgrade. A particular file's signature has changed from F4A3 to 26B1. (For brevity I am using a 16-bit signature, in practice it is much much larger.) When the first client connects to the patch server it receives the updated list of file signatures. The client notices that the file is now old so it requests a patch for F4A3->26B1. The patch does not exist yet, so the reverse-rsync algorithm activates and the client calculates the F4A3->26B1 patch. When that patch has been generated it is returned to the patch server and all future clients can just download the patch and skip the reverse-rsync. After applying a patch, the result is checked to make sure that you actually ended up with 26B1. If you did not, extra rounds of patching are performed.
Some Notes: These extra rounds are consequences of rsync and a security check as well to prevent bad patches from being uploaded to the server. And, normally the release maintainer would "pre-seed" the patch server by patching a clean current version to the new version just before release.
You seem dedicated, I suggest you get on the MUD-Dev mailing list and ask Andrew Tepper for advice. He is lead on A Tale in the Desert. ATITD is a small-scale MMORPG on par with your target of 1500 subscribers (they have over 2000 I believe). When I last kept track of ATITD they had about 5 people working on the project. Andrew Tepper could probably give you a lot of useful feedback on the business aspects of your idea.
Good luck.
Let's assume cost of revenue is only 50% (very generous!) so that leaves us with $450,000 gross profit.
Let's assume a total encumberance of $160,000 per employee (realistic). That gives us enough for 2.8 employees, not including you. That, of course, would be for zero net income.
Not much of a company, eh?
(Encumberance means all costs associated with an employee: ie. salary, taxes, healthcare, office space, electricity, etc. Think of it as TCO for people. It can get as high as $220,000 in large companies.)
Some people have proposed an anti-spam system where spammers need to generate RPOW tokens, but ordinary users can exchange them. Is there anything in the system to prevent copying an RPOW token? If a spammer receives a single good token, couldn't he just make a million copies of that token and send one of each token to each spam recipient? Without collaboration each individual receiver cannot know that it is receiving a duplicated token.
Firstly, I think it is unreasonable to expect mail servers to collaborate to look for duplicated tokens. And secondly, I think that any digital token can be duplicated regardless of any hardware or software copy protection.
A classic example, and one Slashdotters are likely to be familiar with, is the bag checkers at Fry's. They have no right to search your personal effects without cause, and that includes a Fry's bag. Since you just came away from the register with that bag, they have no justification to search it.
I always ignore them, and they have never tried to search me forcibly. They know that they have no right to do so. They can only search you if you meekly allow yourself to be searched.
Similarly, self-taught programmers are good enough for the bulk of programs. Let's face it, programming is actaully quite easy. You don't need a crack team of ivy league computer scientists to organize your MP3 collection anymore than you need to go to the hospital every time you get a little sniffle.
The history of physics is full of theorized particles or fields that never panned out. We just never read about them in textbooks, because who wants to learn things that are wrong. We tell glamorous annecdotes about the hard to find particles that were discovered (e.g. Neutrino) and ignore the theories that were failures (e.g. Ether). So, our perceptions are colored, and we over-value theory.
Please don't fall into that trap. Look at things objectively and critically. No matter how good the theory looks, experimental confirmation is necessary. Physicists believed in the existence of Ether right up until the 1887 Michelson-Morley experiment.
PS. I wanted to provide links to more examples than just Ether, but for the exact reasons I outlined above I had diffculty locating web pages on other failures.
But, this analogy is no good because soft drinks have weight and volume, but stock has neither!
Okay, so replace the soft drink cans with a credit card. You can take the credit card to any restaurant and redeem it for a can of Pep or Coca. Now weight and volume don't matter. Do Pep and Coca sell equally now? No. Pep still sells better, because nobody wants to shell out $144 just to get a drink.
Stock price doesn't matter as far as the financial value of stock, but it does matter for the convenience of buying and selling stock. Therefore most companies split and reverse-split to keep their stock price in a nominal range. And they are correct to do so.
Isn't economics great? So many ways to view the same activity.
PS. Will a real economist please step in and let us know which viewpoint is correct?
2. Computers infected with the worm spam random addresses.
3. Sit back and enjoy the chaos.
Or, even better: If authentication is weak, then have the worm email you and collect the bonds.
I read the article and they basically say that this is possible. Their defense is that you can only lose at most the (small) amount that you keep in your ABM account. However, when your account is depleted what happens next? You can't send email anymore? How do you get your money back? Some kind of insurance claims type procedure? No thanks.
I give ABM two thumbs down.
Q. Why does the game industry { advertise hours of gameplay | not innovate | sell the same game over and over | only make games for males | advertise polygon counts | only make violent games }?
A. Because that's what the customers want.
No Derek Smart thread can be complete without the classic Taco Supreme Commander thread.
Bacteria sems to be a common thread here. Specifically whether they can live on Mars or not. For those who want to find more information on bacteria living under extremely adverse conditions, they are referred to in scientific literature as extremophiles
That would be funnier if it didn't make fun of other people's accents.
1 MW = 1 kg
apollo trip = 6500 kg (the 2500 kg mentioned is extraneous right?)
proposed laser = 1 KW
150 proposed lasers = 150 KW * 1 kg / 1 MW = 150 g
units needed for apollo trip = 6500 kg / 150 KW * 1 MW / 1 kg = 43,333 units (what is a unit anyway? a set of 150 lasers or a single laser? whatever, 6.5 million lasers are needed)
12 GW = ? (huh? I thought it was 1 MW/kg, so who cares how many lasers or units are used it's going to be 6.5 GW)
Can you repost with the math again? I must be missing a conversion somewhere, or there is a typo. Thanks.
a@a.com - 8,980
My life as an engineer is fantastic. I love staying indoors at a desk and exercising my mind. I don't have to suck up to my boss because my industry is a meritocracy. I enjoy the freedom that comes from being able to switch jobs anytime because good people are always in demand. Life couldn't be better.
I am happy that you have finally found your calling in life. But, don't put down my industry. Leave those teenagers alone; let them find their own way. They just might enjoy engineering. I know I do.
This is going to get modded down as flamebait, but it has to be said.
To all the whiners saying it can't be done:
We already have something called DNS. What exactly do you think DNS does? It translates from a portable network address to a hierarchically structured IP address.
To the guys who want to own their IP address:
Suck on it. Get a domain name, that's what DNS was invented for.