My quick Wikipedia-based calculations are that the ISS could match orbits with the moon in 9.2 years if its solar panels were entirely devoted to powering ion engines.
(They wouldn't be, of course, and my other major omission is the need to orbit the moon -- I have no idea how the moon's gravity would perturb the ISS as it approached, I suppose it would increase or decrease orbital transfer efficiency but I don't know which.)
Sources:
Low-thrust transfer - "going from one circular orbit to another by gradually changing the radius costs a delta-v of simply the absolute value of the difference between the two speeds"
ISS Solar Arrays - 4 pairs of "wings" to be installed on ISS, totalling 262 kW (I think; might be half that if I misunderstood "wing"); ISS weighs 1 million pounds
Since it's hosted by Hulu, they won't stream to a computer outside the U.S
Looks like it's fixed now. The homepage reads:
All those outside the USA who have been eagerly awaiting Doctor Horrible's Act 1 should now be able to view it via the Official Web Site. If it doesn't load, try clearing your browser cache and doing a forced refresh of the page (Hold down the Ctrl key while pressing the F5 key).
Prefetching your search results doesn't protect you from viruses any more than just checking the pages you try to load at the time of loading.
What it does, is basically scanning the entire internet, weighted toward the pages its users search for, and I assume reporting back to AVG which websites have malware or suspected malware on them.
The problem with this theory is that malware sites can move around quickly, so learning that domain xzclqqkxzz.com tried to upload a virus to someone's computer 48 hours ago is not especially valuable information.
That's in addition to AV software being essentially impossible to keep up-to-date anyway, you can look up studies but most AV software lets a lot of malware through.
And the increased traffic annoys webmasters because the prefetches are (attempted to be) disguised as actual page fetches, and they come from all over the internet, so we think they're real clicks from real users but they're not. Plus, for some sites the increased load/bandwidth may be a problem.
It's not really the load -- it's throwing off our internal metrics so we don't know what readers are actually interested in. We like numbers, and messing with our stats annoys us.
The promises of Minsky et al. never materialized simply because the early researchers into strong A.I. (which was then simply called "A.I.") didn't know what they were doing and had not even the beginning of a handle on what problems they were trying to solve.
In 1972, Hubert Dreyfus debunked the field's efforts as misguided from the start, and in the couple of decades since he was shown to be absolutely right...
Water injection is used in large engines and high-performance engines. Installing a water injector in a 70 hp Volvo might be a fun project but it's a little silly, as it's not going to give a dramatic improvement in either gas mileage or power.
If your car ran quieter after installing a water injection system, it's because you weren't using high enough octane fuel to begin with, and you were getting engine knock.
(This also has nothing to do with the "car runs on water" claim...)
Well, there are 7 justices nominated by Republicans, and the other 2 were suggested by a Republican. The Court is already fully packed.
The 5-4 decision split along ideological lines, with the five justices most widely considered "more liberal" voting that a CSRT doesn't qualify as habeas. The four considered "more conservative" -- including GWB's two -- voted that secret kangaroo courts are plenty good for any o' them furriners that our president wants to hold without charges.
In a major rebuke to the Bush administration's theories of presidential power -- and in an equally stinging rebuke to the bipartisan political class which has supported the Bush detention policies -- the U.S. Supreme Court today, in a 5-4 decision (.pdf), declared Section 7 of the Military Commissions Act of 2006 unconstitutional. The Court struck down that section of the MCA because it purported to abolish the writ of habeas corpus...
To our country's pseudo-tough-guy "conservatives," the very idea of merely requiring the Government to prove the guilt of the people it wants to imprison for life or execute is so intolerable, so offensive, that they want instead to release them all -- including detainees who are indisputably innocent -- onto a battlefield so that they can be slaughtered by our planes with no trial at all. [...]
The question I put to him again and again was one that he simply couldn't answer: how and why would any American object to the mere requirement that our Government prove that someone is guilty before we imprison them indefinitely or execute them?
Yet the Government's view is that the Constitution had no effect there [at Guantanamo], at least as to noncitizens, because the United States disclaimed sovereignty in the
formal sense of the term. The necessary implication of the
argument is that by surrendering formal sovereignty over
any unincorporated territory to a third party, while at the
same time entering into a lease that grants total control
over the territory back to the United States, it would be
possible for the political branches to govern without legal
constraint.
Our basic charter cannot be contracted away like this.
The Constitution grants Congress and the President the
power to acquire, dispose of, and govern territory, not the
power to decide when and where its terms apply. Even
when the United States acts outside its borders, its powers
are not "absolute and unlimited" but are subject "to such
restrictions as are expressed in the Constitution." Murphy
v. Ramsey, 114 U. S. 15, 44 (1885). Abstaining from questions involving formal sovereignty and territorial governance is one thing. To hold the political branches have the
power to switch the Constitution on or off at will is quite
another. The former position reflects this Court's recognition that certain matters requiring political judgments are
best left to the political branches. The latter would permit
a striking anomaly in our tripartite system of government,
leading to a regime in which Congress and the President,
not this Court, say "what the law is." Marbury v. Madison, 1 Cranch 137, 177 (1803).
In that passage, the Court upbraids the Bush administration,
which sought this unconstitutional law and argued to uphold it, for
claiming that the President has the right to "switch the
Constitution on or off at will." The Court is absolutely correct
about this, there is no doubt that this is what our current President
has attempted. And the Court is correct that this is an attempt to
circumvent the system of separation of powers that is at the heart
of the "basic charter" on which the United States was founded.
The fact that this decision was a slim 5-4 majority,
with this President's two appointees making up half the dissenting
view, is a frightening thought.
That is avoiding the question. The question is if Slashdot is getting some sort of kickback or favor for running this article. The answer is: of course not. We never do that.
You get database backup by replicating to another VM, presumably one in a different "zone" for physical separation. Then that backup VM every n hours stops its replication, dumps to S3, and starts replication back up (exactly like a physical machine would stop, dump to tape or to a remote disk, and restart).
Database high-availability is similar. In the extreme case, you replicate your live master to the master database in another zone that entirely duplicates your live zone's setup (same number of webheads, same databases in same replication configuration, etc)... then if the live zone falls into the ocean you point your IPs to the webheads in the HA zone and resume activity within seconds, having lost only a fraction of a second of data stream.
Having dealt with Slashdot's webheads and databases losing disk, and in some cases having to be entirely replaced, I don't see how persistent storage is a big selling point. I mean it's nice I guess, but not something that I'd sacrifice any functionality for. Applications have to be designed to run on unreliable hardware.
For me, it'd be more about hassle than price. If I'm developing a new service, it starts with just one server and I don't want the hassle of figuring out where the best host is. I want the flexibility to cancel the whole thing with no contract (billed by the hour) and just walk away if it turns out not to be a good idea. I also want the flexibility to scale quickly from 1 machine to 10 and 100 without having to worry about picking out the hardware, billing, power, cooling, network architecture, backup, fixing dead machines, and of course whether the host has room for me to scale.
When the VCs want to know what issues are involved with my service scaling to 100x its current size, they would much rather hear that the single hardware issue is "dollars," rather than that whole long list of unknowns. Dollars are easy.
And from what I can tell, EC2/S3 would scale from one server up to Slashdot size and beyond without much problem. Probably not to Wikipedia size, but I wouldn't be surprised if it could get close. And as someone else noted, they don't have data centers anywhere but the East Coast... but I wouldn't be surprised if they're working on that too (I don't have any inside info, I didn't sign an NDA).
So here's a little about what EC2 actually is, for those of you who don't know. You don't have to reply here, start your own comments;)
The Elastic Compute Cloud was originally designed as a way to host applications that needed lots of CPUs, and the option to expand by adding more CPUs. It's a hosting service that lets you start up virtual machines to run any software you want: they have a wide variety of pre-packaged open-source operating systems you can pick to start up your VMs with.
Starting up a VM takes just a minute or two, and it's point-and-click thanks to the Firefox extension. Each VM comes in one of
three sizes: small (webhead), large (database), and extra large (bigass database). They cost respectively $72, $288, and $576 a month (billed by the hour), plus bandwidth ($0.18/GB out, somewhat cheaper for data going in and there's a price break at 10 TB).
One of the concerns everyone raises with hosting on virtual machines is that if a VM instance goes down, you lose everything on it. It comes with hard drive storage (160 GB on the small size), but if something goes wrong, that data's gone.
I think the rejoinder here is that, on real hardware, if something goes wrong, your data's gone. You never set up an enterprise-level website on the assumption that any particular hardware has to survive. Single points of failure are always a mistake, and backups are always a necessity. When any machine explodes - real or virtual - the question is how fast your system recovers to "working well enough" (seconds, hopefully) and then how long it takes you to get it "back to normal" behind the scenes (hours, hopefully). Those answers shouldn't depend on whether there's a physical drive to yank out of a dead physical machine that may or may not retain valid data.
Which brings up what I think is one of the selling points of EC2: free fast bandwidth to S3, Amazon's near-infinite-size, redundantly-replicated data storage platform. That's a nice backup option to have available. That's part of why, if I were starting a new web service, I wouldn't host it on real hardware. I'd like not having to worry about backups, tapes, offsite copies... bleah, let someone else worry about it.
Slashdot hasn't run many stories on EC2 (none that I know of) because until now it's been a niche service. Without a way to guarantee that you can have a static IP, there had been a single point of failure: if your outward-facing VMs all went down, your only recourse was to start up more VMs on new, dynamically-assigned IPs, point your DNS to them, and wait hours for your users' DNS caches to expire. That meant that while it may have been a good service for sites that needed to do massive private computation, it was an unacceptable hosting service.
Now with static IPs, you basically set up your service to have several VMs which provide the outward-facing service (maybe running a webserver, or a reverse proxy for your internal webservers), and you point your public, static IPs at those. If one or more of them goes down, you start up new copies of those VMs and repoint the IPs to them. No DNS changes required.
I know there are other companies offering web hosting through virtual servers. Please share information about them, the more we all know the better.
Slashdot, and the company that runs it Sourceforge Inc., aren't using Amazon Web Services for anything that I know of. Slashdot runs on real hardware, not VMs, and we're not planning on changing that anytime soon. I don't know anyone using AWS, which is part of why I'm looking for Slashdot reader feedback. My experience with it is limited to starting up some instances and playing around with installing Apache to see how it all works, and I did that on my own nickel. I chatted with someone at Amazon about AWS last year, but I didn't sign an NDA so I learned about today's news through their public mailing list.
Without knowing anything more about this story, my initial assumption is that these were inside jobs using a novel cover story. The "hypnotist" probably split each take with his collaborators. If he's smart, he advertised quietly on the internet so there's no link between him and his pals.
Slashdot Mirror
My quick Wikipedia-based calculations are that the ISS could match orbits with the moon in 9.2 years if its solar panels were entirely devoted to powering ion engines.
(They wouldn't be, of course, and my other major omission is the need to orbit the moon -- I have no idea how the moon's gravity would perturb the ISS as it approached, I suppose it would increase or decrease orbital transfer efficiency but I don't know which.)
Sources:
Low-thrust transfer - "going from one circular orbit to another by gradually changing the radius costs a delta-v of simply the absolute value of the difference between the two speeds"
Ion engine comparisons - 25 kW can produce 1 N thrust
ISS Solar Arrays - 4 pairs of "wings" to be installed on ISS, totalling 262 kW (I think; might be half that if I misunderstood "wing"); ISS weighs 1 million pounds
Moon's orbital velocity = 1.0 km/sec, ISS's orbital velocity = 7.7 km/sec
Google says: 9.2 years
Since it's hosted by Hulu, they won't stream to a computer outside the U.S
Looks like it's fixed now. The homepage reads:
Not a typo, here's a clip from a short period last night before Slashdot banned it:
| user_agent | count(*) |
| Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) | 339 |
| Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;1813) | 57 |
| User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) | 273 |
| User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;1813) | 15 |
4 rows in set (0.03 sec)
Prefetching your search results doesn't protect you from viruses any more than just checking the pages you try to load at the time of loading.
What it does, is basically scanning the entire internet, weighted toward the pages its users search for, and I assume reporting back to AVG which websites have malware or suspected malware on them.
The problem with this theory is that malware sites can move around quickly, so learning that domain xzclqqkxzz.com tried to upload a virus to someone's computer 48 hours ago is not especially valuable information.
That's in addition to AV software being essentially impossible to keep up-to-date anyway, you can look up studies but most AV software lets a lot of malware through.
And the increased traffic annoys webmasters because the prefetches are (attempted to be) disguised as actual page fetches, and they come from all over the internet, so we think they're real clicks from real users but they're not. Plus, for some sites the increased load/bandwidth may be a problem.
It's not really the load -- it's throwing off our internal metrics so we don't know what readers are actually interested in. We like numbers, and messing with our stats annoys us.
The top hit from Google would have told you. It's Amazon's Elastic Compute Cloud.
The promises of Minsky et al. never materialized simply because the early researchers into strong A.I. (which was then simply called "A.I.") didn't know what they were doing and had not even the beginning of a handle on what problems they were trying to solve.
In 1972, Hubert Dreyfus debunked the field's efforts as misguided from the start, and in the couple of decades since he was shown to be absolutely right...
Water injection is used in large engines and high-performance engines. Installing a water injector in a 70 hp Volvo might be a fun project but it's a little silly, as it's not going to give a dramatic improvement in either gas mileage or power.
If your car ran quieter after installing a water injection system, it's because you weren't using high enough octane fuel to begin with, and you were getting engine knock.
(This also has nothing to do with the "car runs on water" claim...)
Also, if you pour dirt into the radiator, it cleans your hoses with the power of mud.
Well, there are 7 justices nominated by Republicans, and the other 2 were suggested by a Republican. The Court is already fully packed.
The 5-4 decision split along ideological lines, with the five justices most widely considered "more liberal" voting that a CSRT doesn't qualify as habeas. The four considered "more conservative" -- including GWB's two -- voted that secret kangaroo courts are plenty good for any o' them furriners that our president wants to hold without charges.
Recommended reading that didn't make it into this story's writeup:
Glenn Greenwald, Supreme Court restores habeas corpus:
Glenn Greenwald, Conservative vs. authoritarianism:
The decision itself, with my favorite passage being:
In that passage, the Court upbraids the Bush administration, which sought this unconstitutional law and argued to uphold it, for claiming that the President has the right to "switch the Constitution on or off at will." The Court is absolutely correct about this, there is no doubt that this is what our current President has attempted. And the Court is correct that this is an attempt to circumvent the system of separation of powers that is at the heart of the "basic charter" on which the United States was founded.
The fact that this decision was a slim 5-4 majority, with this President's two appointees making up half the dissenting view, is a frightening thought.
I used to work for a company that was convinced the next big thing was going to be vertical web portals -- Vortals.
But I think you may be right.
Yep, she's a Rex. Very soft, very opinionated.
Woo! Rabbits!
"Software failure" in that case refers to a failure of Amazon's Xen software that runs your virtual machine.
Amazon doesn't know or care whether your software is "production quality code" or not. You pay $0.10/hr whether your code is debugged or not :)
Adding to Related Links, thanks. Should have done this myself (doh).
You get database backup by replicating to another VM, presumably one in a different "zone" for physical separation. Then that backup VM every n hours stops its replication, dumps to S3, and starts replication back up (exactly like a physical machine would stop, dump to tape or to a remote disk, and restart).
Database high-availability is similar. In the extreme case, you replicate your live master to the master database in another zone that entirely duplicates your live zone's setup (same number of webheads, same databases in same replication configuration, etc)... then if the live zone falls into the ocean you point your IPs to the webheads in the HA zone and resume activity within seconds, having lost only a fraction of a second of data stream.
Having dealt with Slashdot's webheads and databases losing disk, and in some cases having to be entirely replaced, I don't see how persistent storage is a big selling point. I mean it's nice I guess, but not something that I'd sacrifice any functionality for. Applications have to be designed to run on unreliable hardware.
If you think I'm one of the "kids these days," you really are old ;)
For me, it'd be more about hassle than price. If I'm developing a new service, it starts with just one server and I don't want the hassle of figuring out where the best host is. I want the flexibility to cancel the whole thing with no contract (billed by the hour) and just walk away if it turns out not to be a good idea. I also want the flexibility to scale quickly from 1 machine to 10 and 100 without having to worry about picking out the hardware, billing, power, cooling, network architecture, backup, fixing dead machines, and of course whether the host has room for me to scale.
When the VCs want to know what issues are involved with my service scaling to 100x its current size, they would much rather hear that the single hardware issue is "dollars," rather than that whole long list of unknowns. Dollars are easy.
And from what I can tell, EC2/S3 would scale from one server up to Slashdot size and beyond without much problem. Probably not to Wikipedia size, but I wouldn't be surprised if it could get close. And as someone else noted, they don't have data centers anywhere but the East Coast... but I wouldn't be surprised if they're working on that too (I don't have any inside info, I didn't sign an NDA).
Ah, I was using the term to mean data center. Didn't realize they were sometimes physically separated. My misunderstanding.
So here's a little about what EC2 actually is, for those of you who don't know. You don't have to reply here, start your own comments ;)
The Elastic Compute Cloud was originally designed as a way to host applications that needed lots of CPUs, and the option to expand by adding more CPUs. It's a hosting service that lets you start up virtual machines to run any software you want: they have a wide variety of pre-packaged open-source operating systems you can pick to start up your VMs with.
Starting up a VM takes just a minute or two, and it's point-and-click thanks to the Firefox extension. Each VM comes in one of three sizes: small (webhead), large (database), and extra large (bigass database). They cost respectively $72, $288, and $576 a month (billed by the hour), plus bandwidth ($0.18/GB out, somewhat cheaper for data going in and there's a price break at 10 TB).
One of the concerns everyone raises with hosting on virtual machines is that if a VM instance goes down, you lose everything on it. It comes with hard drive storage (160 GB on the small size), but if something goes wrong, that data's gone.
I think the rejoinder here is that, on real hardware, if something goes wrong, your data's gone. You never set up an enterprise-level website on the assumption that any particular hardware has to survive. Single points of failure are always a mistake, and backups are always a necessity. When any machine explodes - real or virtual - the question is how fast your system recovers to "working well enough" (seconds, hopefully) and then how long it takes you to get it "back to normal" behind the scenes (hours, hopefully). Those answers shouldn't depend on whether there's a physical drive to yank out of a dead physical machine that may or may not retain valid data.
Which brings up what I think is one of the selling points of EC2: free fast bandwidth to S3, Amazon's near-infinite-size, redundantly-replicated data storage platform. That's a nice backup option to have available. That's part of why, if I were starting a new web service, I wouldn't host it on real hardware. I'd like not having to worry about backups, tapes, offsite copies... bleah, let someone else worry about it.
Slashdot hasn't run many stories on EC2 (none that I know of) because until now it's been a niche service. Without a way to guarantee that you can have a static IP, there had been a single point of failure: if your outward-facing VMs all went down, your only recourse was to start up more VMs on new, dynamically-assigned IPs, point your DNS to them, and wait hours for your users' DNS caches to expire. That meant that while it may have been a good service for sites that needed to do massive private computation, it was an unacceptable hosting service.
Now with static IPs, you basically set up your service to have several VMs which provide the outward-facing service (maybe running a webserver, or a reverse proxy for your internal webservers), and you point your public, static IPs at those. If one or more of them goes down, you start up new copies of those VMs and repoint the IPs to them. No DNS changes required.
I know there are other companies offering web hosting through virtual servers. Please share information about them, the more we all know the better.
Just in case you were serious... :)
Slashdot, and the company that runs it Sourceforge Inc., aren't using Amazon Web Services for anything that I know of. Slashdot runs on real hardware, not VMs, and we're not planning on changing that anytime soon. I don't know anyone using AWS, which is part of why I'm looking for Slashdot reader feedback. My experience with it is limited to starting up some instances and playing around with installing Apache to see how it all works, and I did that on my own nickel. I chatted with someone at Amazon about AWS last year, but I didn't sign an NDA so I learned about today's news through their public mailing list.
Without knowing anything more about this story, my initial assumption is that these were inside jobs using a novel cover story. The "hypnotist" probably split each take with his collaborators. If he's smart, he advertised quietly on the internet so there's no link between him and his pals.
I have been shown new information and have changed my beliefs as a result :)
Thanks for the correction.