Starcraft II doesn't support LAN play. This is not just a case of needing to be online and authenticated with Battle.net to fire up a server. That would be annoying but could be poorly justified by the improved integration with your online profile.

No, Starcraft II goes out of its way to make playing on a LAN difficult even when everybody has purchased the game and has logged on to Battle.net.

Suppose you're at a LAN with a bunch of other dudes (or gals, let's be optimistic) and you're fortunate enough to have an Internet connection so that you can all get onto Battle.net. As best I can tell, you have two options for getting in a game together:

Option 1: Invitations

• Go around and find out each other's user names on Battle.net and add each other as "friends".
• Have the host start a private game and then invite all the relevant people to the game.
• Other players accept the invitation.
• Fingers crossed packets will actually get routed over the LAN (this has been hinted at but I haven't tested it.)
  (update: a friend informs me that everything goes through Singapore. Yay.)

Option 2: Public and Pray

• Have the host start a public game, which allows anyone on Battle.net to join.
• Tell the players what map it is.
• Players try to connect and hope they get the right server.
• Host kicks other players who try to join because they figure it's a public game.
• Again, fingers crossed regarding routing.

This is seriously crap.

As the people who are reading this probably know, I help run LANs this year where we don't have Internet. I had a glorious plan to allow people to connect to Battle.net through my phone's 3G connection so that we could get some games happening, but nobody's going to want to go through all the above to make it work. Sure, I'd probably do it because I really like Starcraft but I would feel like a deluded fanatic saying "Hey you should play this game! It'll be great! We just have to do all this bullshit to make it work, but you know you want to!"

It's like a fricking iPhone. Sure, I could buy one and jailbreak it to do what I want. Sure, somebody's going to hack SC2 so it can be played on a LAN eventually. But I shouldn't have to do it. Antifeatures are lame. I may not have bought an iPhone but because of my lack of moral conviction Blizzard already has my money and they don't give a toss what I think from here on in.

I should learn to find Battle for Wesnoth exciting or something.

Answer: It's all in the levels editor. Go to "Levels..." in the Colors menu and you're greeted with a level-editing histogram.

• Moving the middle triangle in Input Levels to the left is the same as increasing the "Shadows" slider in iPhoto.
• Moving the right triangle in Output Levels to the left is the same as increasing the "Highlights" slider in iPhoto.

And with a bit of tinkering you can work out how to do other things too. Hooray.

I think I'm a little behind the times. This book was published in 1991 and it feels like everyone involved in computing apart from me knows about it by now. The fact that the story is over 20 years old now makes the book fascinating for a number of reasons apart from the simple tracing of the cracker. Stoll goes into detail about the lifestyle at the Lawrence Berkeley Laboratory and his own thoughts on the political and social responsibilities of computer network users.

The story is from a time when, at least in academia, computer systems were relatively open. Multiple users shared computers generally in order to work collaboratively. One of his conclusions in the book is that we must work hard to maintain trust rather than put energy into abusing that trust, because of the damage it does to the network and how easily we can work together.

I guess we failed. Not that I was old enough to do anything about it but it's a damn shame to see that that's how it went. It's a fact of online life now that everything online needs to be locked down. Even if you want to be share your data, the more mechanisms you make available for that data to be shared the more software you're exposing which could potentially have bugs in it. And inevitably there are people out there who wish to exploit those bugs, for a variety of reasons. Sigh.

The second interesting point was in his epilogue discussion about the transmission of a worm: a conclusion that computer networks have robustness due to the diversity of types of nodes. A virus for a VAX can't run on an IBM system, etc. Though he couldn't possibly have foreseen it at the time, we're seeing a heavy convergence towards web applications right now. What used to be a diversity of operating systems with standard network protocols is now becoming a diversity of web browsers with standard markup and javascript.

I think he has valid point even though it was made quite a while ago now. The ability for us to have operating system/browser diversity derives directly from open standards and open implementations. Look what happens when there's a bug in Adobe's flash implementation. Oops, everyone's vulnerable. And being closed source doesn't help. Let's keep our standards open.

The final point which I found particularly interesting was Cliff's own change of opinion. Initially he took a fairly loose apathetic view that breaking into other systems for fun could be just playful or even a good thing if it exposed problems. By the end of his ordeal he decided that the very act of messing with other people's systems is damaging simply because of the goodwill and trust which is lost, not to mention the amount of time which people like him have to spend working on problems they wish they didn't have.

A great book. Go read it sometime. You wouldn't have to be a computer person to appreciate it either, but it probably helps. :)

Those of us against it are trying to cut through this nonsense and point to the bigger issues. Suppose that they were only out to block child pornography websites. The material is obviously bad. The material is obviously illegal. But it still does not make the filter the right policy because of the level of the trust we put in the Government not to abuse their power now and in the future. (And in reality they want to block "refused classification" material, which is a very fuzzy definition which definitely includes material which is legal to own.)

So can we trust the Government? My instinct says no. However there's nothing like the benefit of hindsight. Gizmodo has recently posted a short article about what's happened in Turkey since the introduction of their filter, including a 3-minute video report [youtube] from Al Jazeera about how badly the situation has devolved. Not only are all kinds of websites being blocked for political or religious reasons, but no progress is being made in the attempt to have the laws appealed.

Could it happen in Australia? You bet. You bet our civil rights on it.

EDIT: Another highly recommended article about the flaws of censorship in general:  The State of trust: it's a one way street

Does the person who owns the status update receive the comment on their seed and potentially have the opportunity to review it before it is broadcast? That seems reasonable. Really, though, the comment belongs to the person who wrote it. Shouldn't their seed have the right to send it out to all its peers regardless of what the person who posted the original update thinks?

It's fairly obvious in this case that the status update seed should be the definitive source of any comments. We all appreciate the idea that if the status update belongs to you, then you should have some level of control over what content is associated with it.

The problem becomes more complicated when you take a photo of your friends and want to share it on your seeds, including tags of the identities of everybody in the photo. The way Facebook operates is that even though you own the photo, the user who is tagged has the option of removing that tag, whether or not the photo poster wanted to keep it there. Clearly this is isn't enforceable in Diaspora where you only have control over your own seed.

On one hand, the photo and its tags belong to the person who shared the photo and contributed the tags. On the other, the tagged person doesn't own anything except the identity, but it would be nice if they could have some control over being tagged. How should this system mediate this?

The critical thing is that we're communicating with our friends. I would propose a system like this: your friend's seed announces its policy on photos: (a) Please don't tag me, (b) If you tag me, please don't display it until I've reviewed the photo, or (c) Go ahead, tag me.

When you attempt to tag this friend in a photo it will check on the policy. If it's option (a) Don't tag, then it will refuse to do so (or at least make you jump through hoops. Shame on you for not respecting your friend's wishes). If it's option (b) Check first, it will send away a review request without you having to think about it. If it's option (c) Tag me, it will simply apply the tag.

Not only does this work to allow people to stipulate their tagging wishes, but it falls back on good old human respect to get along. Just because you have the technical ability to do something disrespectful to a friend doesn't mean you should. Conversely, where we can use technology to facilitate flexible interaction rather than dictate policy, we should.

Right now Internet users are tending to solve the problem by delegating responsibility for their data to a third party who is supposed to keep it secure and supply it back to the user on request. This way you can upload data from one of your computers and download it (even automatically) on the others when you need it. For things like your files, email and contacts there are services available such as Dropbox, Apple's MobileMe and Canonical's Ubuntu One.

Some kinds of data are more sensitive than others. As a matter of policy I dislike making my data available to other parties unless it's necessary and I do it explicitly. It is well known amongst those who use email encryption that the encryption should be used all the time so as to not draw special attention when you do send something sensitive. This is also one example of keeping your data your own as a matter of course. Another advantage is that you use the same workflow all the time.

Suppose, as has happened before, I need to work with a digital copy of an art piece where all hell would break loose if it was leaked or shared. It would be downright stupid of me to upload it to somebody else's computers where I'm no longer directly responsible for the data. If I don't upload it, it can't leak, so the most sensible thing is not to do so. There's unlikely to be a problem even if I did use someone else's storage, but I don't want to take the risk. Now I need to start using special methods to move the data around such as an external hard drive or scp. How inconvenient. All I really want to do is to easily copy stuff over a network to the other computers without a middle man.

The trouble is it's a pain to set up that kind of service on the Internet right now. It won't really be viable on a large scale until IPv6 takes off in a big way. When that happens every device on the Internet will be individually addressable (and hopefully not excessively firewalled). Over the next couple of years this will become more and more attractive, particularly as the speed of Internet connections increases.

But why stop at ultra-sensitive data? Many of us store things like our email, instant messenger logs and social networking data on other people's computers. Google might even store your music and stream it to you. If we have a convenient method of synchronising our own data on our own computers we may as well do so and thereby eliminate the risks of losing direct control of the data. And we get an awesome backup system for free.

So we have this neat Diaspora thing coming out in a few months. It's going to provide decentralised peer-to-peer encrypted social networking. It'll hopefully be a little like Facebook with absolute control over to whom your data is given. I'm going to love playing with and possibly seriously using Diaspora but I doubt it will deliver enough convenience to steal many Facebook users, at least for a while.

I'm seeing something more here. The Diaspora devs explain that they want to make an extensible framework where anybody can create any sort of application or payload for sharing between peers. I reckon they're seeing a bigger picture where peer-to-peer is a necessary part of keeping our data private on the Internet. Initially, though, they're creating a secure social networking tool. That's a great idea because that's where users are hurting the most right now.

Diaspora or a project like it must succeed. I refuse to acknowledge a future of computing where users are expected to surrender data to others to get their work done on the Internet. It may not matter even most of the time. There is always a place for your own computer, your own data, your own control.

The cloud is getting more convenient all the time. With a little resourcefulness and work, peer-to-peer systems between our own computers can be convenient too. Then we won't have to throw out our old expectations of privacy for the sake of that convenience.

(John Gilmore famously once said, "The Net interprets censorship as damage and routes around it." However,) "The Net" is not some robot but the result of how everyone uses it.

Since the Internet is effectively a democracy in its own right, do you believe that any nation should have the right to impose regulations upon it? Could it have its own sovereignty?

On the broadcast the part in parentheses was omitted. As I watched the panellists attempt to answer the question (or dodge the question) I quickly realised that apart from Brett Solomon, the intent of my question was mostly missed. In hindsight I see that by trying to fit my question in a small number of words I obscured my meaning.

Nonetheless the word "sovereignty" in particular brought up some good discussion about how sacred the freedom to do what you like on the Internet is. An on-screen tweet also suggested that it was more like anarchy then democracy, citing /b/. This is a fair point but still not quite what I meant.

I would like to elaborate a little about what I did mean. I do not necessarily think that the following is true. It is more of an interesting thought experiment for me, which is why I attempted to pose it to the Q&A panel.

The Proposal

The Internet is evolving all the time and I consider this to be very much like a democratic process. I'm going to stretch this analogy a bit. Instead of a piece of land on which we live, we have a relatively boring network over which we can make connections between computers using generally the TCP/IP suite with IPv4 and IPv6.  There is a lot of complicated technology which makes it happen but fundamentally that's all we're getting. An empty block.

On one level standardisation is generally democratic. Most Internet standards are developed by working groups with input from the entire industry -- the community and the businesses which run and use the Internet. We have requests for comment, and draft and approved specifications. Best of all, these working groups are doing this work knowing that it has to meet the needs of the stakeholders. Their standard has to gain general acceptance. A political party's policy must also gain general acceptance for them to be elected. Otherwise we go and use a different standard or vote for a different party, or make our own.

Standards are mostly about the Internet at the level of those who implement it. On another level there is a form of democracy in what services Internet consumers choose to use. Lots of people use email. Lots of people use peer-to-peer services. Lots of people use web servers. Lots of people use Facebook. The services which have server and client software, those which are supported, are those which have gained widespread popularity. Nobody is forced to use any of them, but it is inefficient to work against the grain because you cannot communicate with others as easily. This process of being driven to accept what the majority wants is also a democratic feature of the Internet.

The major point where this analogy falls apart is that democratic governments in the physical world can outlaw certain activities. This is not enforceable on the Internet because whatever the "crimes" are, they can be obscured easily. You can't encrypt your stealing of a car, but if someone invented an invisibility cloak that would be a similar effect.

Yet by and large this global community of Internet users feels that the benefits of this freedom outweigh the disadvantages of not being able to outlaw activities. This is where John Gilmore's famous quote applies. He originally made the statement about USENET but he stands by it to this day in a more general sense too. If censorship is applied to the Internet users change which services they use; they change how they use the Internet and therefore its form and features in order to circumvent that censorship. By a process of consensus, users do not want the censorship to happen. If the majority of users wanted to embrace censorship or any other arbitrary restriction, the changes necessary to work around it would not gain traction. People would say, "Stuff Tor. Proxies for rent? Hah, they'll be out of business in no time." More people would block Tor users because they feel that the trouble caused through anonymity is not outweighed by the ability to circumvent censorship.

The Internet community is big. It has representatives in the form of users from every nation. It is a community which is saying in a more-or-less democratic way that Governmental censorship is unwanted.

In that context, who is the relatively small Australian Government to say, "We know better than the Internet community. We should apply blacklisting for RC content."?

It is not even a question of the technical implementation of the policy. It is a restriction upon the Internet community which has by majority decided that it does not want the restriction. But the Internet community is much larger than the Australian community or Government, so there may be an argument to say, "The Internet overrules the Australian Government. No filtering." If so, should national Governments of the physical world respect that?

In saying so it is not suggesting that anarchy should be permitted on the Internet either. Crimes on the Internet are generally crimes in the physical world too.  Let the nation which has sovereignty over the physical space in which the criminals reside and the crimes are taking place enforce the laws of that area. However, they must not disregard the wishes of the (larger therefore more important) Internet community in their enforcement.

Well Then

Am I crazy, onto something or simply logically invalid? I haven't yet decided. Given that the Internet is a shared global resource and medium I think we have to at least settle on the issues of what individual nations may or may not do before we can fully evaluate censorship or national law enforcement proposals.

It's some sort of 802.1X beastie. Setting it up on GNU/Linux is mostly a trial-and-error affair. My current settings are WPA2 Enterprise security, PEAP authentication, MSCHAPv2 inner authentication, and an AusCERT-certified identity whose root certificate isn't included in any normal root certificate packs.

They don't actually tell you what the settings are. The current way you're supposed to set it up on Windows or Mac OS X is to run some java-ish program which asks you for your administrator password and proceeds to mess with your settings such that it should work. Furthermore, if you're running Windows and it can't detect antivirus software it forces you to install McAfee Antivirus before it will mess with your settings. But that's okay, because McAfee is awesome.

Nonetheless it can be made to authenticate and have your computer on the University network. At this point you have access to the Internet, sort of. You can make DNS requests, or open TCP connections to destination ports 80, 110 and 443. Previously you had to explicitly go through proxy.utas.edu.au to get your web traffic out, but this year they brought in transparent proxies (edit: Not true. See comments). This is a minor improvement, but still doesn't do much for my IMAPS email, Google Talk, or anything else I want to do.

The general technique I've used for this other traffic is an ssh tunnel to my computer at home, using corkscrew where necessary to get through an HTTPS proxy. ssh -D will set up a SOCKS proxy on the local computer, causing all connections to be made via the remote computer (my computer at home). All I have to do is tell pidgin and Thunderbird and possibly firefox to use a SOCKS proxy at localhost and I can use the Internet how I like.

I wish I could say that having negotiated all these challenges I can relax and concentrate on my studies. This year they introduced a new problem: connections drop out. After some random interval of normally 2-30 seconds most TCP connections will stop having packets go either way. New connections continue as normal. I have no idea what routing problem is responsible for this but it's damn annoying.

Even HTTP requests can be affected by this. Sometimes I'll load a wikipedia page and half the maths images won't load. There is one little bit of respite: if a connection lasts for longer than about 30 seconds, it will tend to live more or less forever. Weird. This gives me a solution to web browsing: I keep on trying to establish an ssh tunnel to my home computer, and once one has managed to stay established for over half a minute, I can start using it to do web browsing through the SOCKS proxy.

This is where I've been at for the last seven or eight weeks but it's getting seriously frustrating killing ssh connections until I manage to establish a tunnel which stays up. I wanted a program to automate this process. Let's make a lot of ssh connections, poke them every ten seconds for half a minute, then grab one that's still alive and start another channel with that ssh TCP connection.

This can be facilitated using the ssh ControlMaster option (-M -S). Each of the simultaneous connections puts a socket in /tmp. Then when I want to use a particular TCP connection I launch another ssh process with -S to indicate the socket to use and also with the -D option which enables the SOCKS proxy behaviour on that connection. Then I want that first background connection to hang around until I'm done with the second, then die automatically.

So I've written a program that does just that: urlyconnect. If you're at UTAS you too might find it useful. I've tested its functionality on Debian and Ubuntu GNU/Linux but I see no reason why it shouldn't run on a Mac. If you use Ubuntu, note carefully the instructions in the README about the required version of OpenSSH.

Well, that's that done. Time to go and do something related to my degree.

This is a tutorial introduction to getting your computing units right. The history of these issues is covered in extensive detail at Wikipedia.

File or Data Size

Everyone knows that computers store things as 1s and 0s. These are called bits. (Short for binary digits).

All modern computers represent things like letters and numbers with a group of 8 bits, which is called a byte. That is; there are 8 bits to every byte.

Convention is to use a lower case b to refer to quantities of bits and an upper case B to refer to a number of bytes. 220B refers to 220 bytes.

If we want to talk about lots of bytes there are SI prefixes available to us:

• k (kilo) 1,000
• M (mega) 1,000,000
• G (giga) 1,000,000,000
• T (tera) 1,000,000,000,000

So it is perfectly okay to talk about 936 kB, 1.24 Mb, 50 GB, referring to kilobytes, megabits and gigabytes respectively. It is not okay to talk about 936 mb because the prefix m (milli) means one-thousandth of a bit. You can't have parts of a bit. Please don't use the wrong case.

Binary prefixes

Confusingly, often people use terms like kB, MB and GB while meaning something slightly different.

When a computer stores a bunch of bytes in memory it tends to group them into chunks of powers of 2. This is because it needs to be able to give each spot in memory an address and it's easier to build hardware conforming to:

All addresses of the form 000000xx xxxxxxxx are stored in chip 1, 000001xx xxxxxxxx are stored in chip 2, etc.

In this example every chip has 10 bits of address space and can store 1024 bytes. If you were lazy, you would say that each chip stores 1 kB of data. But that means 1,000 bytes, not 1,024!

Similarly, with 2^20 bytes you get approximately one million: 1,048,576. So you can't say that this is a "megabyte" really, because that would mean exactly one million bytes.

There are two main solutions to this problem. The first and most common is to ignore it. This entails using kB, MB, GB, etc. and letting the person reading it guess exactly how many bytes you mean. This works most of the time because usually an approximate file size is good enough. Will the file fit on my flash drive? About how long will this take to download? Near enough is good enough.

But I'm an engineering student so I find this imprecision annoying, and sometimes we need to be explicit about what we mean. For this we have a method developed by the International Electrotechnical Commission:

• Ki (kibi) 1,024
• Mi (mebi) 1,048,576
• Gi (gibi) 1,073,741,824
• Ti (tebi) 1,099,511,627,776

If you ever see numbers like 3 KiB, 2.3 GiB, etc., you know exactly how many bytes they really mean. Better yet, if you always use those forms to represent the powers of 2, you also know that the ordinary SI prefixes always mean powers of 10.

The only downside is that it sounds ridiculous to say "mebibytes" out loud. But hey, it might be cool some day. It's only been around since 1996. If you look carefully, some computer software will express quantities in MiB or GiB. DC++ is an example.

Transfer Speeds

There are two main things to say about speeds. First of all, a transfer speed is how much data you can transfer in a given amount of time. Therefore the speed is an amount of data per second.

When speaking out loud it's convenient to talk about a "one-point-five megabit connection" but when written it should be "1.5 Mb/s".

Secondly, standard Internet connection speeds are quoted in bits per second. When you download files in your browser it usually shows you bytes per second. If you have a 1500 kb/s connection, to estimate your download speed in bytes per second you need to divide that number by 8, which is 187.5 kB/s. In reality it won't be quite that fast, but there's a big difference in the number depending on whether you're using bits or bytes.

Conclusion

I'm not as pedantic as some people. I have a lecturer who will happily write distances in Mm (megametres) instead of thousands of kilometres like almost anybody else would do.

All the same, the chances are you'll run across these numbers quite a lot and if you know exactly what they mean, more power to you. I will also be happier if I am reading something you've written and don't have to make mental conversions.

Finally and most importantly: sometimes it can be ambiguous. There is such a wide range of internet connections available these days that a download speed of 1 MB/s or a download of speed of 1 Mb/s could both be reasonable. If you're working out how long something will take to transfer you can't rely upon common sense to guess the correct form.

This is my newest radio. It's called a Pixie II. It also happens to be the first amateur-band transmitter I've ever made.

These things are pretty cool. It is a continuous wave (CW) (or morse code) transceiver operating at a fixed frequency determined by a crystal on an HF band. Mine's configured for 80 metres using a 3.579545 MHz colorburst crystal. To move it to another band you just need to change the crystal and the L and C parameters of the antenna pi network.

The associated circuit description claims that it puts out a couple of hundred milliwatts. I'm not sure exactly how much power it does produce as it doesn't move the needles on my SWR meter but I intend to do the theoretical analysis sometime.

So what is it? Refer to the schematic. It's a Colpitts crystal oscillator running permanently at the transmission frequency. When the morse key is closed this pulls down the emitter of Q2, allowing it to amplify the oscillator into the antenna. When the switch is open the received AC is multiplied by the local oscillation frequency (direct conversion) and the result is superimposed on the supply voltage and applied as the input to an LM386 amplifier. This amplifier then provides a fixed (!) gain of 200 to the multiplied signal and in my case is attached to a 1 W 8 Ω speaker.

Despite the simplicity of the circuit I'm pleased to say that it really does work. I've tested both transmission and reception with my much fuller-featured Yaesu FT-7B.

There are a few bits missing, which is very much the point. The intention of the Pixie II is to provide the basic operating radio so that the operator can make improvements. In this case I would like to add a proper audio power amplifier with volume control, an automatic gain control for the received signal and some tuning capacitance. I'll need to take some measurements but I'm hoping I can get a stable 20 kHz tuning range with appropriate loading capacitance on the crystal. I could also experiment with an antenna filter with a sharper roll-off.

When I make these improvements, coupled with a decent antenna there's no reason why I couldn't have proper QSOs with this radio or even run it in a contest. Being low power and on 80 metres, it is not going to get much more range than Tasmania unless we get some crazy sun spots so I'm hoping that I'll be able to find some other morse operators within the state. If you're a radio amateur you should build one of these.

Perhaps I should learn morse code too.