Except that OpenVZ is a better way to go in that case. For fairness it should be mentioned that aside from OpenVZ there is also Linux VServer which does a few things better than OpenVZ (though OpenVZ does some things it does not). Our preference has always been VServer, it's a well-run project with emphasis on quality and well thought through design rather than quantity.
With Linux Vserver you only run one kernel on your system where with Xen each virtual server runs its own kernel. This presents some limitations for Linux Vserver. For example the guest virtual servers cannot have the network loopback interface lo. But almost all of these I could live without.
To me, one kernel is an advantage, not a limitation. A kernel upgrade on a VServer box is a one-step operation, whereas on a Xen (or like) you have to repeat it for every guest.
Also a great thing about VServer is that the filesystem can be shared between host ang guest. So I can run one backup on the host, which takes care of all the guests.
Another thing I like is the ability to "enter" a guest from the host by simply switching the context - no need to actually log in.
And the virtualized loopback and iptables is just a matter of time - the alpha branches of VServer already have it.
I should also mention that aside from Vserver there is something called OpenVZ, which is the same concept and more features. What turns me off about OpenVZ and Xen is that the community around these projects is commercially sustained, which means that the project evolution will gravitate in a direction that satisfies shareholders and that the project would be greatly impacted by a business failure (which happens quite often these days).
Vserver on the other hand is a truly indepndent open source community, very much like the communities that drive other most succesful projects out there. I've been following this project for a couple of years now, things may not move as fast, but folks are involved out of the love for technology, and the quality of the software reflects this.
So... Since Guido got an offer and Larry Wall didn't, does that mean that Google has tipped its hand in the debate?
Google's always been pretty open about heavy Python use. There is fairly interesting presentation by Greg Stein about Python at Goole here (audio only).
Trying to talk sense into these people is like trying to argue with a Scientologist about psychiatry or with a Southern Baptist about evolution.
"Sense" is neither one view or the other. If we develop ways to produce and consume energy that do not pollute the environment, the debate on whether global warming is caused by humans would be completely irrelevant.
What bothers me is the folks who cannot accept that the answer is somewhere in between, it has to be a total disaster scenario or complete denial.
Of the two news items that read "So and so has almost positively proven the cause of global warming" or "So and so has developed a way to reduce co2 emissions by 2.76%" - which one is more sensational, which one qualifies as "front page"? Which sceintist will get more funding and publicity - the one behind the former story or the latter? Yet which of has contributed more to society? That's problem with us people, hype-driven beings...
I think I buy into this "ajax" thing
on
Ajax in Action
·
· Score: 5, Informative
Paul Graham's got an opinion on Ajax in his Web 2.0 essay.
I too initially thought "What's the big deal, it's just
JavaScript". But I'm now actually reading the "Ajax in Action" book,
and it looks like there is something to it. It's not so much about the
tools you use (which are indeed JavaScript and CSS pretty much), it's
more about the architectural view of the application, where you think
of the browser hosting your application rather than
content and the server produces data rather than
content and how Ajax coding is not just
get-the-javascript-to-work-and-move-on like in the old days, but rather
not unlike any other language, requiring same level of discipline.
Anyhow, the book explains it better, I recommend it.
I use the built-in bluetooth to connect to my laptop and use the phone as a modem.
Who do you use as a carrier? My current phone is/w Verizon, but all googling shows that they explicitely disable DUN on the treo, whereas Sprint now has it enabled - makes me think about just switching to Sprint, even though I really like Verizon's coverage - Verizon often has a signal in most remote places like the mountains of West (and non West) Virginia or some remote part of the bay where no other carriers have signal.
Get a treo. It has a thumb keyboard and several ssh clients. Add in PDANet and its a wireless modem with a USB connection to your laptop.
I think I looked at that, and the problem is that I couldn't find any info on what it takes to get Mac OS X to recognize the treo as a modem (I think there may be a BlueTooth way to do it, but I'd need to get a new PowerBook, mine has no BT). PDANet appears to be Windows-only. Aside from that the treo does look like a pretty nifty device.
This nokia 770 has USB and bluetooth so you can but a usb/luethoot keyboard and install shh
Yeah, but that's the whole point - I don't want to lug a bunch of devices with me like an idiot, I just want small thing that I can take anywhere that would be no more burdening than wearing a watch and know that I can log in and get a command line prompt on my server. And if I'm going on a long trip, then I'll take my laptop with me and use the device as a modem.
Slightly OT - but has anyone figured out a way one can get a device that provides two things (1) a (thumb) keybard and ssh access on its own (2) can serve as a modem for your laptop via USB (my powerbook doesn't have bluetooth). And preferably this device would be compatible with CDMA/EVDO, but I'll settle for GSM just as well. AND I don't want to pay $600 for it, AND I dont care for any other fancy-shmancy features at all.
Not quite. Without "unsigned," c may or may not be -1, depending on your compiler and its settings. The C standard allows char to be signed or unsigned by default.
NOW are you surprised?:)
Nope:)
is surprize good?
on
Java Puzzlers
·
· Score: 2, Informative
There are several occurrences that really surprised me
I'm somewhat puzzled by the premise of the book. I thought C/C++ was full of puzzlers, and that Java was supposed to fix all that. Puzzlers may be cute, but they are definitely bad (except for job security may be). BTW, my little test shows that this example also applies to C, except that it isn't as surprising since you have to specifically declare the variable as unsigned, e.g.
From TFA "Most open-source projects do fail because they typically
don't have full-time employees, but only a few volunteers who a lot of
times are kids," Born [the CEO] said.
... and some CEO's need to grow up, I'll be off to buy a nano, which works without the "help from the open source community" (who are mostly kids, mind you).
My guess is this article is just some paid (and poor quality) PR. Read this to learn more
about how these articles end up published.
The main reason I don't like separation, at least as it was implemented with FreeBSD in my expereince, is the lack of complete resource separation. You can have one virtual "machine" go crazy and chew up all available memory, or use up all entries in the process table.
Yep, it looks like FreeBSD jail's development didn't get far past the basic implementation of jail id's. We started out with FreeBSD jails and then switched to Linux VServer because VServer was advancing while jails just kinda sat there. Where they differ is the VServer people look at each one of those limitations you described and rather than just saying "this is how it is, learn to live with it", they try to address it - so to prevent one context from chewing up CPU there is a token-bucket CPU scheduler, there are various memory limits, some interesting stuff being contemplated - e.g. using the rate of page swap-ins in combination with a token-bucket for fair memory access. There are lots of little issues, but that's what makes this project interesting.
Vservers are nothing more than a fancy chroot and some other minor things.
This is not a fair statement. I can say that Xen is not even as fancy as a CPU emulator.:-) Actually a "fancy chroot" is a very complex challenge - in fact the reason there are so many hardware emulators and not so many separation technologies is because implementing hardware emulation is simpler.
But yes, Xen and VServer are completely different beasts.
I think the benefits of being able to run multiple operating systems are more numerous than just the single case of development that you listed. For a hosting company, the ability to provide multiple operating systems provides a great deal of flexibility. And for users, it gives one the abillity to check out various new distributions easily, as well as the potential to use different distros for specific tasks for which they are best suited
All true. Let me rephrase the requirement here. Let's say I run an
operation that requires a large number of servers. I know the
application and I know the distribution I want. For example I am an
ASP that hosts an application that does something and each instance is
a separate server, let's say I need 10,000 of those. I want all
servers to look exactly alike. I'm not going to play with
distributions, I don't need separate operating systems, I am strictly
after efficiency - I want to fit the most hosts onto a hardware box
with minimal overhead.
I also want to have one filesystem to backup on the physical box, I
want to be able to enter virtual servers seamlessly for management
purposes. I want to have to maintain one kernel per hardware box.
In this scenario a separation solution such as Vserver, jails or Zones
wins hands down.
There are a few problems with Xen. First, it's i386 only. Second (and this is the biggest problem IMO) - Xen is venture-backed, and seems to be extremely eager to show their investors a return. Nothing wrong with that, but it's important to consider the motivation, and the consequence of a funding pull back. If XenSource does not turn out to be a great business, then will Xen still be developed and maintained? Why not wait a little bit, in the open source world quality over quantity matters and time pressure should not influence development.
Also, there is another project that I plug every chance I get - Linux Vserver. Unlike Xen, this is a purely volunteer effort, and is very innovative and attemtps to solve a difficult issue. Unlike Xen, these guys actually do not want to be in the mainline for now, becuase they think it will slow down development. Because Linux VServer is taking a different approach to virtualization (better known as separation, which was pioneered by FreeBSD jails and is also now supported in Solaris), the end result is cross-platform, i.e. runs on any architecture that Linux runs on.
Now in the past whenever I posted about Linux VServer a lot of folks said that Xen allows you to run multiple operating systems and that that is why it is so useful. I think that in reality running multiple OS's isn't all that valuable - the only case where it may be very useful is software development, but that's a tiny fraction of the Linux users. We've been using Linux VServer for hosting, and we are absolutely convinced that this is the right solution - for using Xen for example would introduce all kinds of problems (starting with resource bloat).
Yet unfortunately the OSS world has become PR driven lately. Very few people are technically capable of looking at things based on its merits and just go after the things that have the most buzz, not realizing that the buzz is artificially generated.
We have a page on our
site with some calculations on how much energy is being saved because
we're using Linux VServer and why dedicated servers are not
environmentally-friendly (at least not with the current technology -
this may change). The numbers are probably off a bit, but they give
you some idea.
Also the street price for a 20A circuit in a datacenter is
$200-$300, while the cost of a megabit is $100 or less. So a rack of
servers that requires two power circuits and pushes 3Mbps (not an
unusual scenario) costs twice as much in power than in bandwidth.
That's in his lifetime. Since 1998, I sent 27,171 emails (granted, an e-mail is much easier to sent than a snail mail letter). It's hard for me to count how many I received (counting spam it's probably in the millions).
I find it hard to believe that someone with a Perl background is complaining that Ruby has a quirky syntax.
Heh... As someone with Python background, I definitely find Ruby syntax very quirky. My theory is that most Ruby users are people who started out with Perl and would never learn Python "because of the whitespace issue" (in truth they just didn't have a need, the time or what it takes to break old habits). Then as Python started becoming more and more popular, it became more and more difficult to admit that Python is indeed a really good language, while their language of choice was really getting tired by the minute. Then came about Ruby - now you can learn a language other than Perl or Java and yet not admit defeat to Python.
My humble advice is that if you made the jump from Perl (or Java) to Ruby, might as well go all the way and learn Python.
In total, we have about 12 websites for every person on the planet.
74,409,971 / 12 = we have approximately 6,200,830 people on this planet:-) You probably meant to say we have about 12 websites for every 1000 people on the planet.
Slashdot Mirror
when you add an extra leap second...
There are only two places in the US where datacenters can be built - Silicon Valley and Northern Virginia.
more like several hundred million, actually
http://ww23.rr.com/index.php?origURL=http://www.google.com
Now we can make phone calls as root!
To me, one kernel is an advantage, not a limitation. A kernel upgrade on a VServer box is a one-step operation, whereas on a Xen (or like) you have to repeat it for every guest.
Also a great thing about VServer is that the filesystem can be shared between host ang guest. So I can run one backup on the host, which takes care of all the guests.
Another thing I like is the ability to "enter" a guest from the host by simply switching the context - no need to actually log in.
And the virtualized loopback and iptables is just a matter of time - the alpha branches of VServer already have it.
I should also mention that aside from Vserver there is something called OpenVZ, which is the same concept and more features. What turns me off about OpenVZ and Xen is that the community around these projects is commercially sustained, which means that the project evolution will gravitate in a direction that satisfies shareholders and that the project would be greatly impacted by a business failure (which happens quite often these days).
Vserver on the other hand is a truly indepndent open source community, very much like the communities that drive other most succesful projects out there. I've been following this project for a couple of years now, things may not move as fast, but folks are involved out of the love for technology, and the quality of the software reflects this.
Google's always been pretty open about heavy Python use. There is fairly interesting presentation by Greg Stein about Python at Goole here (audio only).
"Sense" is neither one view or the other. If we develop ways to produce and consume energy that do not pollute the environment, the debate on whether global warming is caused by humans would be completely irrelevant.
What bothers me is the folks who cannot accept that the answer is somewhere in between, it has to be a total disaster scenario or complete denial.
Of the two news items that read "So and so has almost positively proven the cause of global warming" or "So and so has developed a way to reduce co2 emissions by 2.76%" - which one is more sensational, which one qualifies as "front page"? Which sceintist will get more funding and publicity - the one behind the former story or the latter? Yet which of has contributed more to society? That's problem with us people, hype-driven beings...
Paul Graham's got an opinion on Ajax in his Web 2.0 essay.
I too initially thought "What's the big deal, it's just JavaScript". But I'm now actually reading the "Ajax in Action" book, and it looks like there is something to it. It's not so much about the tools you use (which are indeed JavaScript and CSS pretty much), it's more about the architectural view of the application, where you think of the browser hosting your application rather than content and the server produces data rather than content and how Ajax coding is not just get-the-javascript-to-work-and-move-on like in the old days, but rather not unlike any other language, requiring same level of discipline.
Anyhow, the book explains it better, I recommend it.
I use the built-in bluetooth to connect to my laptop and use the phone as a modem.
Who do you use as a carrier? My current phone is /w Verizon, but all googling shows that they explicitely disable DUN on the treo, whereas Sprint now has it enabled - makes me think about just switching to Sprint, even though I really like Verizon's coverage - Verizon often has a signal in most remote places like the mountains of West (and non West) Virginia or some remote part of the bay where no other carriers have signal.
Get a treo. It has a thumb keyboard and several ssh clients. Add in PDANet and its a wireless modem with a USB connection to your laptop.
I think I looked at that, and the problem is that I couldn't find any info on what it takes to get Mac OS X to recognize the treo as a modem (I think there may be a BlueTooth way to do it, but I'd need to get a new PowerBook, mine has no BT). PDANet appears to be Windows-only. Aside from that the treo does look like a pretty nifty device.
This nokia 770 has USB and bluetooth so you can but a usb/luethoot keyboard and install shh
Yeah, but that's the whole point - I don't want to lug a bunch of devices with me like an idiot, I just want small thing that I can take anywhere that would be no more burdening than wearing a watch and know that I can log in and get a command line prompt on my server. And if I'm going on a long trip, then I'll take my laptop with me and use the device as a modem.
Slightly OT - but has anyone figured out a way one can get a device that provides two things (1) a (thumb) keybard and ssh access on its own (2) can serve as a modem for your laptop via USB (my powerbook doesn't have bluetooth). And preferably this device would be compatible with CDMA/EVDO, but I'll settle for GSM just as well. AND I don't want to pay $600 for it, AND I dont care for any other fancy-shmancy features at all.
NOW are you surprised?
Nope :)
I'm somewhat puzzled by the premise of the book. I thought C/C++ was full of puzzlers, and that Java was supposed to fix all that. Puzzlers may be cute, but they are definitely bad (except for job security may be). BTW, my little test shows that this example also applies to C, except that it isn't as surprising since you have to specifically declare the variable as unsigned, e.g.
int b = -1;
unsigned char c = (unsigned char)b;
Without "unsigned", char is -1, as expected.
From TFA "Most open-source projects do fail because they typically don't have full-time employees, but only a few volunteers who a lot of times are kids," Born [the CEO] said.
My guess is this article is just some paid (and poor quality) PR. Read this to learn more about how these articles end up published.
The main reason I don't like separation, at least as it was implemented with FreeBSD in my expereince, is the lack of complete resource separation. You can have one virtual "machine" go crazy and chew up all available memory, or use up all entries in the process table.
Yep, it looks like FreeBSD jail's development didn't get far past the basic implementation of jail id's. We started out with FreeBSD jails and then switched to Linux VServer because VServer was advancing while jails just kinda sat there. Where they differ is the VServer people look at each one of those limitations you described and rather than just saying "this is how it is, learn to live with it", they try to address it - so to prevent one context from chewing up CPU there is a token-bucket CPU scheduler, there are various memory limits, some interesting stuff being contemplated - e.g. using the rate of page swap-ins in combination with a token-bucket for fair memory access. There are lots of little issues, but that's what makes this project interesting.
Vservers are nothing more than a fancy chroot and some other minor things.
This is not a fair statement. I can say that Xen is not even as fancy as a CPU emulator. :-) Actually a "fancy chroot" is a very complex challenge - in fact the reason there are so many hardware emulators and not so many separation technologies is because implementing hardware emulation is simpler.
But yes, Xen and VServer are completely different beasts.
I think the benefits of being able to run multiple operating systems are more numerous than just the single case of development that you listed. For a hosting company, the ability to provide multiple operating systems provides a great deal of flexibility. And for users, it gives one the abillity to check out various new distributions easily, as well as the potential to use different distros for specific tasks for which they are best suited
All true. Let me rephrase the requirement here. Let's say I run an operation that requires a large number of servers. I know the application and I know the distribution I want. For example I am an ASP that hosts an application that does something and each instance is a separate server, let's say I need 10,000 of those. I want all servers to look exactly alike. I'm not going to play with distributions, I don't need separate operating systems, I am strictly after efficiency - I want to fit the most hosts onto a hardware box with minimal overhead.
I also want to have one filesystem to backup on the physical box, I want to be able to enter virtual servers seamlessly for management purposes. I want to have to maintain one kernel per hardware box.
In this scenario a separation solution such as Vserver, jails or Zones wins hands down.
There are a few problems with Xen. First, it's i386 only. Second (and this is the biggest problem IMO) - Xen is venture-backed, and seems to be extremely eager to show their investors a return. Nothing wrong with that, but it's important to consider the motivation, and the consequence of a funding pull back. If XenSource does not turn out to be a great business, then will Xen still be developed and maintained? Why not wait a little bit, in the open source world quality over quantity matters and time pressure should not influence development.
Also, there is another project that I plug every chance I get - Linux Vserver. Unlike Xen, this is a purely volunteer effort, and is very innovative and attemtps to solve a difficult issue. Unlike Xen, these guys actually do not want to be in the mainline for now, becuase they think it will slow down development. Because Linux VServer is taking a different approach to virtualization (better known as separation, which was pioneered by FreeBSD jails and is also now supported in Solaris), the end result is cross-platform, i.e. runs on any architecture that Linux runs on.
Now in the past whenever I posted about Linux VServer a lot of folks said that Xen allows you to run multiple operating systems and that that is why it is so useful. I think that in reality running multiple OS's isn't all that valuable - the only case where it may be very useful is software development, but that's a tiny fraction of the Linux users. We've been using Linux VServer for hosting, and we are absolutely convinced that this is the right solution - for using Xen for example would introduce all kinds of problems (starting with resource bloat).
Yet unfortunately the OSS world has become PR driven lately. Very few people are technically capable of looking at things based on its merits and just go after the things that have the most buzz, not realizing that the buzz is artificially generated.
We have a page on our site with some calculations on how much energy is being saved because we're using Linux VServer and why dedicated servers are not environmentally-friendly (at least not with the current technology - this may change). The numbers are probably off a bit, but they give you some idea.
Also the street price for a 20A circuit in a datacenter is $200-$300, while the cost of a megabit is $100 or less. So a rack of servers that requires two power circuits and pushes 3Mbps (not an unusual scenario) costs twice as much in power than in bandwidth.
And here's another article on this issue. And another.
Einstein sent more than 14,500 letters.
That's in his lifetime. Since 1998, I sent 27,171 emails (granted, an e-mail is much easier to sent than a snail mail letter). It's hard for me to count how many I received (counting spam it's probably in the millions).
Heh... As someone with Python background, I definitely find Ruby syntax very quirky. My theory is that most Ruby users are people who started out with Perl and would never learn Python "because of the whitespace issue" (in truth they just didn't have a need, the time or what it takes to break old habits). Then as Python started becoming more and more popular, it became more and more difficult to admit that Python is indeed a really good language, while their language of choice was really getting tired by the minute. Then came about Ruby - now you can learn a language other than Perl or Java and yet not admit defeat to Python.
My humble advice is that if you made the jump from Perl (or Java) to Ruby, might as well go all the way and learn Python.
In total, we have about 12 websites for every person on the planet.
74,409,971 / 12 = we have approximately 6,200,830 people on this planet :-) You probably meant to say we have about 12 websites for every 1000 people on the planet.