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Today I just noticed the following advert on one of my web pages:
MINIX3 is a new reliable
free operating system. Smaller
than Linux. Try it It’s free!
www.minix3.org
This made me think about some of the potential ways of advertising free software projects. It seems that in some ways Google Adwords is not the only way that can be used for advertising free software, and in some ways isn’t the most effective.
I believe that the most effective method would be to ask people to advertise the project. I am generally positive towards the aims of the Minix project and am happy to give them some free advertising if asked (I’ve just given them a free advert above without being asked).
While Google adlinks and equivalent things in blog posts are easy to set up, effective advertising may require something more. A series of pictures (in different sizes and color schemes) for the link would help, and the project would ideally have a specific landing site for people who see the advert. Someone who sees an advert targeted to newbies will have different requirements from the web site to someone who already knows about it and typed the URL in from memory! For a big campaign you would probably want to have multiple landing sites for different adverts targetted at different people.
One example of how this can be used is my Bonnie++ page which gets about 6000 hits a month – many of which are from users of proprietary Unix. Linux users often have Bonnie++ as part of their distribution and don’t have much of a need to visit my web site so I expect that even though the vast majority of Bonnie++ users run Linux the proportion of site visitors might not be so strongly in favour of Linux. I would be happy to place an advert on that page to encourage proprietary Unix users to use the most free distribution of Linux if someone was to prepare the advert and give me some HTML code I can easily add to my site.
To some extent the web site for every free software project could be used to advertise some related projects (or projects that are liked by the people who run the site).
If you are a contributor to a free software project that you think I would like then feel free to prepare an advert and send it to me. If it fits with what I’m doing then I’ll give you some free advertising!
Blogs are also a good mechanism for advertising free software projects, but it seems that this is already being used a lot – having said that…
As a gratuitous plug: my favourite distribution of Linux is Debian (here are my Debian blog entries) and I run NSA Security Enhanced Linux (SE Linux) on all my machines (here are my SE Linux blog entries).
Xen (a system for running multiple virtual Linux machines) and has some obvious benefits for testing Heartbeat (the clustering system) – the cheapest new machine that is on sale in Australia can be used to simulate a four node cluster. I’m not sure whether there is any production use for a cluster running under Xen (I look forward to seeing some comments or other blog posts about this).
Most cluster operations run on a Xen virtual machine in the same way as they would under physically separate machines, and Xen even supports simulating a SAN or fiber-channel shared storage device if you use the syntax phy:/dev/VG/LV,hdd,w! in the Xen disk configuration line (the exclamation mark means that the volume is writable even if someone else is writing to it).
The one missing feature is the ability to STONITH a failed node. This is quite critical as the design of Heartbeat is that a service on a node which is not communicating will not be started on another node until the failed node comes up after a reboot or the STONITH sub-system states that it has rebooted it or turned it off. This means that the failure of a node implies the permanent failure of all services on it until/unless the node can be STONITH’d.
To solve this problem I have written a quick Xen STONITH module. The first issue is how to communicate between the DomU’s (Xen virtual machines) and the Dom0 (the physical host). It seemed that the best way to do this is to ssh to special accounts on the Dom0 and then use sudo to run a script that calls the Xen xm utility to actually restart the node. That way the Xen virtual machine gets limited access to the Dom0, and the shell script could even be written to allow each VM to only manage a sub-set of the VMs on the host (so you could have multiple virtual clusters on the one physical host and prevent them from messing with each other through accident or malice).
xen ALL=NOPASSWD:/usr/local/sbin/xen-stonith
Above is the relevant section from my /etc/sudoers file. It allows user xen to execute the script /usr/local/sbin/xen-stonith as root to do the work.
One thing to note is that from each of the DomU’s you must be able to ssh from root on the node to the specified account for the Xen STONITH service without using a password and without any unreasonable delay (IE put UseDNS no in /etc/ssh/sshd_config.
The below section (which isn’t in the feed) there are complete scripts for configuring this.
Continue reading Xen and Heartbeat
In a comment on my previous blog post a question was asked as to who benefits when customers are able to use cheap electricity.
The answer is that the electricity company benefits the most! When electricity sources such as wind and solar power which can vary in capacity are used the electricity would be cheaper when there is adequate or excess supply. The electricity would be cheaper then to encourage customers to use power hungry devices at those times rather than when the electricity supply is reduced. The larger the capacity of back-up power plants such as gas-fired plants the larger the overall cost of the system (having extra peak-load capacity that is unused most of the time is a waste of money).
However the company that I once worked for on a project related to this was not an electricity company. I can’t name the company due to the confidentiality agreement but if the project ever goes into production I’ll blog about it.
Recently some of the major investment banks have been focussing on how climate change affects business. I think that with these developments there will be a lot of new investment in environment related technologies. Probably if a few people started work on an embedded Linux box for scheduling power use they could have a good chance of getting some investment. The ideal feature list would include control and monitoring over the Internet, the ability to schedule operations based on power price (received from the grid via a technology similar to X10) and local conditions (how charged the batteries are in your photo-voltaic system). It would control devices via standard X10 modules (which can control the power to the device) as well as directly interfacing with machines that need to be turned on all the time.
I would be happy to offer more suggestions via private email to anyone who is interested in implementing this.
A question that people often ask about wind power (and was asked in the comments section of my previous post) is what can be done when the wind speed decreases in an area. There are several methods that can be used to address this problem.
The easiest option is to simply have wind farms spread out over a large area and interconnects that can spread the load. This greatly reduces the problems but is not a total solution.
The next step is to have a series of power plants that can quickly ramp up supply to meet the demand. One good option for this is gas-fired power plants, while they aren’t ideal for the environment they are cheap to build and can react quickly to changing demand. If a gas fired plant is only used when wind speeds are low it should on average be running at a small fraction of it’s peak capacity and use little fuel. Another good option is hydro-electric power which can be turned on quickly, which doesn’t produce any CO2 emissions and is already used widely (about 10% of Australia’s electricity is provided by hydro-electric power).
The ideal solution is to have every user of grid power know when the electricity is cheap (when there is a surplus of wind power) and when it’s expensive (when gas or hydro power is being used). Then non-critical services can be run when electricity is cheap. For example you could put clothes in your washing machine and program it to start the wash when electricity becomes cheap, some time during the day there will be a cheap time and the washing will get done. Once consumers know when electricity is cheap (via X10 or similar technology) they can use that information to determine when to use electricity generated from photo-voltaic cells on their roof and when to use grid power. The same technology can be used for heating and cooling of your home or office, turning off the A/C for an hour or so is only going to be a problem in the middle of summer or winter, for most of the year any heating or cooling could be done with cheap electricity. These technologies are all being developed at the moment (I once briefly worked on a system that could be used as a pre-cursor to managing home electricity use for times of cheap electricity).
# foo=bar
# name=foo
# echo ${!name}
bar
The above example shows how to make a bash environment variable reference the value of another.
# echo ${!f*}
foo fs_abc_opts fs_name
The above example shows how to get a list of all variables beginning with “f” (NB the wildcard can only go at the end).
Ben Fowler writes about the issues related to nuclear power in Australia. He spends 8 paragraphs discussing the issues on the “Right” side of politics – of which 6 concern the an Australian nuclear weapons capability and then spends 3 out of 5 paragraphs related to the “Left” side explaining that he thinks that everyone who opposes nuclear power is a Luddite.
Ben didn’t bother providing any links or statistics to back up his claims, so I’ll assist him in analysing these issues by providing some facts that we can discuss.
In March Spain had wind power provide 27% of all electricity (making wind power the main source of power for the country). I blogged about this at the time. While Spain has an ongoing program of building new wind power stations the majority of wind turbines in Spain are quite old (the Model T of wind power) and not nearly as efficient as modern turbines that would be installed for Australian power plants.
The Danish government has announced plans to use wind power for 75% of their electricity. Denmark has a much smaller land area than Australia, which means that generating so much electricity from wind power is more technically challenging for them than it would be for us. A larger land area means that when one area has low wind speeds other areas can be used to provide power.
For home electricity generation wind turbines have not yet been proven to be practical. The linear speed of the blade is determined by the wind speed and the rotational speed is therefore a factor of the wind speed divided by the radius of the blades. This means that smaller turbines have higher rotational speeds which causes more noise (bad for getting council approval), also to avoid turbulence a wind turbine will ideally be some distance above the ground (8 meters is good) which again gives problems when getting approval. The O’Connor Hush Turbine is supposed to solve the noise component of this problem. It will be interesting to see whether home based wind power becomes practical in future – if so I would like to get an O’Connor turbine on my house!
Home solar power has been proven to work well, in the form of both solar-electric and solar hot water (I know several people who have been happily using them for years). You don’t get cold showers when the sun isn’t shining, you instead use gas or electricity to heat the water (it’s a standard feature in a solar hot water system). Also your home electricity doesn’t go off when the sun stops shining, you have batteries that are charged during sunny times to run things overnight, and when they get flat you pay for power from the grid.
It is quite realistic to stick solar power systems on every roof in the country. The added cost to the process of building or purchasing a house is negligible and the benefits include having electricity when mains power is unavailable (NB water is used in generating electricity from coal or nuclear power plants so a bad drought will eventually become a time of limited mains power). Even the smallest home solar electric system will produce enough electricity to power a fridge and freezer 24*7 so it’s a very useful backup for essential power. The government is subsidising the installation of solar electric systems, so it seems that they expect everyone to get one eventually.
Dr. Ziggy Switkowski (the main advocate of nuclear power in Australia) says “the introduction of a carbon tax could make nuclear power the cheapest option by the 2020s”. In consecutive paragraphs Ben derides “carbon trading” and claims that nuclear power is “practical”. Unfortunately the main advocate of nuclear power in Australia does not believe that it is practical without a carbon tax. Ziggy also states that it would take at least 15 years to complete a nuclear power plant, unfortunately we don’t have the luxury of waiting for 15 years before starting to try and reduce the damage that we are doing to the environment. The Stern report makes the economic consequences of inaction quite clear.
I am not a Luddite. I oppose nuclear power because of the risks related to accidental release of radioactive material and the routine release of radioactive material as part of the uranium mining process, and the dangers related to long-term storage of nuclear waste (let’s not assume that Star Trek science can make it all non-radioactive). Nuclear power is not cost effective for Australia and will take so long to develop that it won’t save us from the serious economic damage predicted by the best scientific models as presented in the Stern report.
For large scale power generation wind power works now, can be easily implemented and has no hidden costs or risks. There will never be a Chernobyl type accident with wind power, it is inherently a safe technology. For small scale power generation (something you can add to your home) solar power works well, is not expensive (when considering the price of a house and especially when the government subsidy is counted) and has the potential to seriously reduce the amount of carbon dioxide produced.
A default RHEL4 install of a Rackspace (*) server contains a cron.d file named /etc/cron.d/rs_rhncheck that runs a job to check for Red Hat Network updates. In the default configuration this would send out a message every day indicating that up2date did nothing. To only get email when there is something interesting happening I changed the cron.d file to call the following script. The checksum is compared against the checksum of the output of up2date when it does nothing (I guess I could have tested the return code for diff). So when up2date either installs a package or decides not to install a new kernel package (or other important package) then I get an email.
#/bin/sh
/usr/sbin/up2date --nox -u > ~/up2date.out
SUM=`md5sum ~/up2date.out | cut -f1 -d\ `
if [ $SUM != "65c57b05b24bd8f656a0aec0d6db725a" ] ; then
cat ~/up2date.out
fi
(*) Rackspace support is really good. If I was paying I might look at other options but for my clients I am happy to recommend them without hesitation.
Just over two days ago I sent a DMCA take-down request to nixforce.com for copying my content in violation of the non-commercial license that I offer, I have not had a response from them and they have kept mirroring my site.
I have just sent a DMCA take-down to tierzero.net which appears to be their ISP. The email address listed in the whois record for that ISP bounces as does the postmaster address.
It seems that I’m not the only person with this problem, Antti-Juhani Kaijanaho is also having problems with them. Any suggestions on how to deal with them would be appreciated.
One possibility that I will eventually persue is to file a DMCA request with Google, this can result in their Google Adwords account being terminated.
The first thing you need is to have meta keywords in the pages. The solution I discovered for doing this is the All In One SEO Pack, this automatically makes the categories of a blog post become meta keywords, allows adding arbitrary meta keywords when editing the blog post, and supports keywords for the entire blog. It also re-writes the titles to have the title of the post appear before the title of the blog in the <TITLE> tag which is rumored to be a good thing to do.
The next thing you want to do is to create a Google sitemap. A sitemap is an XML file that describes all the URLs in your web site which tells Google (and other search engines) the last change dates of all the URLs and the change frequencies (or how often they should be checked for changes). Note that the format is called Google Sitemaps because Google invented it, other web search engines also use the same format. To generate my sitemap I use the Google Sitemaps Generator which tells earch engines to index my main blog page daily and the category pages weekly (which is configurable). It also has an option to notify Google of changes by pinging the Google service.
Having multiple names for the same web page hurts you when it comes to search engines. Having two separate pages at the top of page 2 is not nearly as good as having one page on page one! To solve this problem I use the Permalink Redirect plugin to make sure that each page has only one URL pointing to it. This plugin also allows redirecting the feed URL to feedburner.com. Feedburner serves the feed data (thus saving you some bandwidth if you are on a slow link) and also tracks statistics on it which are interesting.
Under the Writing section of the Options menu there is an option to enter a list of URLs for update services that can be notified of every post. I use http://rpc.pingomatic.com/ and http://rpc.technorati.com/rpc/ping. The Update Services entry in the WordPress Codex has more information on how this works.
Social networking sites such as digg.com can direct a large amount of traffic to your site if you write about a popular topic. The Share This plugin is the simplest way I found of adding social networking hooks to WordPress (I tried a few others that had both less functionality and less ease of use).
Finally before publishing a post, I often check the Google Adwords Keyword Tool. This often gives me ideas on how to make the meta tags and title match what people are searching for.
In response to my comment and post about the cost of driving to work there was a comment on the blog post I responded to suggesting that a small car is better value for money than a hybrid car.
The claim was made regarding a Nissan Pulsar, but to investigate this I decided to compare the Prius with the Corolla Hatchback, as far as I can tell the Corolla Hatchback is the nearest non-hybrid car to the Prius that Toyota sells (being similar in size, weight, and performance). Comparing cars of different make adds extra variables into the equation. Unfortunately the Toyota web site fails to provide specifications for the Prius and only provides a PDF file with minimal information on the Corolla, but it is enough for some minimal calculations.
A car company run by intelligent people would publish the specs on all their vehicles and provide a search form to compare selected models. The Standard Performance Evaluation Corporation has a good search method that allows easy comparison and ranking of items in their database (here is an example). It would be good if Toyota would permit us to compare models in their car range in a similar manner.
According to the Toyota web site the Prius uses 4.4L/100Km when driving in the city and the manual transmission version of the Corolla Hatchback uses 7.4L/100Km (7.7 for the auto). For the average 16,000Km that an average Prius owner drives that would save 480L of petrol which would save about $700 at current petrol prices.
The Corolla Ascent Hatchback (the cheapest of all Corollas) is $21,000 while the cheapest Prius is $37,400. If you compare the Prius with the cheapest Corolla then it’s a $16,400 price difference. If you save $700 per annum then it won’t cover the interest on a $16,400 loan or match the interest rates earned by a bank term-deposit if the $16,400 was invested. So it seems apparent that at current petrol prices (NB petrol prices are expected to increase) and with average Prius driving patterns a Prius will not be more economical than a cheap Corolla.
Currently the Commonwealth Bank of Australia offers 6.05% interest on term deposits of between $10,000 and $25,000. This means that $700 per annum would be the interest on a term deposit of $11,500. If we compare the Corolla Ultima Sedan at $32,000 with the Prius at $37,400 the difference in price is less than $11,500 – but the cars have incomparable sets of luxury and safety features. The Prius i-tech appears to have a super-set of the luxury and safety features of the Corolla Ultima Sedan but at $46,900 is again going to cost more for the average Prius driver.
The Prius is a very quiet car to drive, there is almost no engine noise (when driving at speeds where the Petrol engine is operating there is usually more noise from other vehicles) and no gear changes (handy if passengers are consuming hot or sticky drinks). It has a good set of safety and luxury features and is also a prestige car (no-one will say “oh wow, you’ve got a Corolla”). If you assign a dollar value to these features then a Prius may be the most economical car that meets your requirements!
Finally, let’s keep in mind the fact that petrol prices are steadily increasing. If you save $700 by driving a Prius this year then you may save $1000 next year. There is also the option of converting a Prius to a plug-in hybrid which will be a useful option if petrol prices hit $10/L! Also the amount of money saved will depend on the use of the car. If you are running a courier or taxi business then a Prius will probably be a lot more economical than a Corolla due to the greater distances travelled and the travel in the slow city traffic that the Prius was designed for.
PS All prices are in Australian dollars and concern products on offer in Australia, I would like to see comments from other people who perform the same calculations for their countries.
Update: If this interests you then you may want to read other posts I filed under the Environment and Cars categories.
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