Here’s an example. Look at this code. I dare you even to try running it. You’ll end up with an error.

public static void main(String[] args) {
	int magic = 10;
	if (magic < 20);
	{
		System.out.println("weak magic");
	}
	else
	{
		System.out.println("strong magic");
	}
}

The error is of course, uncommunicative of the true problem. Did you spot the error yet?

syntax error on token “else”, delete this token

The problem here isn’t the else or even the if. No, the problem is a semi-colon. Seriously. Take a look at the if-statement expression. The oddity comes about when you actually see the semi-colon attached to the end of it. And because the if-statement ended there, the else has no preceding pair so it has no choice but to error out.

This example is actually a clear cut case of putting a semi-colon after an if-statement expression. Imagine you didn’t have an error to remind you what you just did. You might just have a plain statement and proper following brackets.

public static void main(String[] args) {
	int magic = 10;
	if (magic < 20); {
		System.out.println("weak magic");
	}
}

Without the else to throw an error message up, how easy would this be to spot? It’s tricky. What if your if-case was a rare edge case condition that you were hard pressed to demonstrate in testing but you theoretically knew it existed? You’d almost never know this wasn’t work until your nuclear reactor began to melt down.

The moral of story: kids will do what you tell them and mind you semi-colons at the end of constructs.

First, we have At The Nexus #14: Super Ultra Mega Bonus Points with yours truly and of course Matthew Petschl.

This week Matthew Petschl, fire-wielding extraordinaire, and Ryan Rampersad reveal the third annual Physics Day with dry ice and cannons. In the news, we cover everything Apple: Mountain Lion, iPad 3 and Apple TV. After that, we touch upon two failed announcements, Amazon Prime memberships, solid state limits, improved MySQL performance, the horribly designed Windows 8 logo, and more!

Then we have The Universe #3: Science for Americans, with Sam Ebertz, myself and special quiet guest, Matthew Petschl. (Do you see a trend where there are only three people actually on the network?)

This week, Sam Ebertz and Ryan Rampersad have specual guest, Matthew Petschl, the pyro-technician extraordinaire and discuss continued NASA news, DNA robots, Fermilab sigma-results, the mysterious hypernucleus, ice melt, a fantastic discussion on exo-planet discoveries leading to verifiable inputs for Drake’s equation and more!

wget is smart enough though to offer a background option that will allow it to be decoupled from the terminal process that started it.

Startup:
  -V,  --version           display the version of Wget and exit.
  -h,  --help              print this help.
  -b,  --background        go to background after startup.
  -e,  --execute=COMMAND   execute a `.wgetrc'-style command.

This allows me to freely leave the connection hanging, and it’ll still continue at home without me. But what about progress now? Ever heard of tail?

Usage: tail [OPTION]... [FILE]...
Print the last 10 lines of each FILE to standard output.

There’s an another option that will allow me to follow the increasingly added data to the file too, essentially appending it to the original 10 lines. In short, it will add 10 lines to the screen as soon as they are ready. When you started the background wget you also were told about the wget_log file: “wget-log”.

So just run a tail -f wget-log and you’ll see the output of the progress of your super massive download that is decoupled from your terminal session! It’s fantastic.

This episode was delayed a little but now that it’s up, it’s an incredible show with lots of fun and jokes. If you’re in a science major, this is required listening. If you’re not, then well, you should listen to this so you’re “well rounded“. So listen to The Universe #2 – Competition We’re Afraid Of at The-Nexus.tv.

Duplicate local variable

Unfortunately, I didn’t grab his erring source code earlier, so I can’t give the true real world source. Nevertheless, my own crafted code should illuminate the problem sufficiently.

public static void main(String[] args) {

	int magic = 10;
	if ( 10 < 11 ) {
		int magic = 12;
		magic++;
	}

}

Imagine you had a variable declaration and initialization at the top of some method. Then later you attempt to create another variable with the same name as before, but inside of a construct like a for loop or if. Unwittingly, you have attempted to redeclare an already declared variable.

Why doesn’t the IDE or compiler know that it’s a syntax error in that case, and that you obviously cannot redeclare variables? Java’s just funny like that, but I suspect it has something to do with the scoping rules in Java. The magic variable inside of the if-statement should be separate, and it is telling you it’s a duplicate, not that it isn’t allowed. So I suppose that’s helpful.

In short, the easy fix is to rename the inner-conflicting variable. So the magic that’s in the if-statement could be magic2 and anything that references it in the if should also be updated. That’s clear enough. The other possibility is to remove the int declaration. Imagine you were simply setting value instead of declaring. It’s an easy mistake to make, especially when you’ve a bunch of declarations repeated.

Happy deduplicating!

Just run (clear), as it is a procedure, you need the parenthesis.

This works in MIT Scheme. If you see a ;Unspecified return value, don’t worry about it. It simply means that the (clear) procedure returns nothing.

I’d like to introduce to you the first expansion of The-Nexus.tv: The Unvierse. The Universe is a show all about science. Sam Ebertz, the host, is a student at the University of Minnesota and majoring in Astrophysics and Computer Science. Sam is a mathematics professional and interested in all forms of science, and he is great at speculating at the future at relating these obtuse angles to the laymen among us.

On the first episode of The Universe, Spark A Revolution, Sam and I discuss:

• Sam’s Anachronism
• Reading minds with neuroscience
• NASA’s lack of funding and the general climate causing this

And more! With over an hour of discussion, Sam and I share our initial thoughts on our second semester at the University of Minnesota and some of the things we like and dislike about the scheme based computer science, 1901.

At The Nexus

In other news, this weekend had no At The Nexus recording. Besides the news week being a little slow and disinteresting, Matt, woodworking extraordinaire, and I were building a server rack for his new computing cluster. We may have a slightly longer episode this Friday at our usual time with, hopefully, a live streaming going.

Website updates

Since my server died a couple weeks ago, I haven’t had a chance to make any modifications to The-Nexus.tv website. There are some points I need to address. There is a distinct lack of comments on the website. Comments at the stage we’re at would be disappointing. While I was posting and hosting the podcasts here on this blog, we received typically a single comment on the podcast. There is little purpose in moderating yet another comment form when Facebook, Twitter and Google+ will do, since that’s where all the traffic comes from anyway.

Since I added the new streaming feature, it would be nice to have a link on the navigation that shows this feature. Or maybe, even magically, have the live streaming box replace the hero-section while we’re live, though that may be an adventure for another day. I’ve written an initial hosts page contain short biographies of our show hosts, but I don’t want to publish it yet until we actually have more than just three hosts.

So I’ll be getting this done as soon as I get my server back online, which will probably end up being another weekend or two, if I’m lucky. If anyone has a spare reasonably fast SATA drive, that would boost those times.

And that’s this week TNTV update.

Pay for what you use. No penalties. No waste.

Select you plans based on how many minutes, text messages and megabytes you think you will use. That’s what we bill you. Next month you will be credited or charged the difference based on your actual usage. Watch a video to see how it works.

These plans are no-contract, so it’s monthly. So for someone who makes very few calls, no data but sends 2000 texts a month, this would be a great deal as it’s only $17. You can click on the price points for the usages and it’ll show you the cost + surcharges (tax). Data is a little expensive, and the irony in this is that some phones sold via Ting are 4G so your data will drain even faster, if your battery doesn’t first. Honestly, my 3G usage isn’t ever above 500 and rarely above 200 megabytes per month. In fact, in the last 30 days, I have used about 30 megabytes. And I’m a heavy user.

But I think the bigger story here is in the actual handsets. These are top-tier phones. Obviously, you have to pay the price of a contract phone so these aren’t exactly cheap. The Motorola Photon, announced last year at the same time as the Triumph, is their crown jewel. The phone is great, it has a nice screen, well reviewed stability, half way decent UI (blur) and probably other goodies. Oh, and it’s fast. So it’s worth it, right? But is it worth $545? Up-front and on the spot? I couldn’t afford a coffee this morning and I will not be able to afford a ~$600 when it’s a year old. Few people buy iPhones at the unlocked price, and this isn’t even an iPhone, it’s just a Photon, and those are bombarding me right now through the Mechanical Engineering windows. Anyway, Ting has less expensive while still impressive phones as well. Excluding the Photon, there are two other 4G options that will range from $300-$400 depending on the screen size and processing power you’re after, or if you prefer HTC to Samsung. For a more reasonable price, you can forgo the 4G, cling to the outdated 3G and embrace your inner WiFi and prepare to wait with a 800 MHz processor in the Samsung Transform. It’s probably fast enough for normal people but I don’t think I could tolerate the speed on that device. And it’s so tiny. Ting has again copied the de-facto standard in low end models, that being the Optimus series, specifically the Sprint-branded Optimus S (lest it be a T, T for Ting, not another Mobile), which is mostly identical to the Optimus V, except more yellow. Finally, they have a $100 Sanyo for those who want Android but don’t want hair.

Ting is offering a couple feature phones that nobody wants and some data-access devices, and I surmise for a relatively good price.

At the bottom of the pages on the Ting website, it has a great disclaimer that I think will answer the question many people are probably asking: “Are you somehow owned by Sprint? Like those other guys?” And the answer would be, “Although Sprint provides access to its network, Ting is entirely responsible for the service.” Or, in short, no. That’s great. Because Sprint needs to compete with Virgin Mobile specifically. Boost is too gangster.

You can tell someone was thinking when they design the Ting website, because I can link to this directly. Let’s say you’re having a huge surge in phone usage one month, and then you stop using it so much. You’re billing is not insane, you’re not overcharged. Instead, you get to pay for more you used than your existing plan, and if you go under your existing plan usage, you can get credited that amount back. So you’re pay for what you used. (Except that $6 automatic fee for being on the service, presumably.) Revolutionary? I think not. Finally? Yes. I never use 500 minutes. I hardly use 100 minutes. It’s a pity there is no in-between to match up to Virgin Mobile’s talking time tier.

So, overall? I like the idea Ting is bringing to the pre-paid no-contract market. The site is full of quips that make me smile, “Paying for extra for tethering? That’s like charging for the soup spoon. We only charge for the soup.” And another good one is, “Select one of the very small computers below. (Most of these can also make phone calls.)” Things like that are very hard to come by in a corporate culture company. It’s refreshing. Don’t think it ends there either, how about their support number? 1-855-TING-FTW Oh yes, for the win, indeed. I want Virgin Mobile to evolve faster too, so perhaps this will encourage the growth I want to see. It’s the oddest thing to see Ting on the network that serves the competition though. Stranger things have happened, I suppose.

So, great job, Ting, on entering the market. I wish you well.

• $0.000 per GB – storage under the monthly global free tier » 0.164 GB-Mo
• $0.00 per request – PUT, COPY, POST, or LIST requests under the monthly global free tier » 67 Requests
• $0.00 per request – GET and all other requests under the monthly global free tier » 451 Requests

So this means over three weeks, there were nearly 70 administrative actions like uploading, setting permissions and so on, and nearly 500 GET requests. We’re using a minimal amount of storage, since we’re only saving the ready to go audio files on S3, though this would increase drastically if I included the raw audio. I also have details about the bandwidth.

• $0.000 per GB – data transfer out under the monthly global free tier » 4.281 GB
• $0.000 per GB – data transfer in per month » 0.325 GB

In just a few weeks, we’ve already used nearly 5GB of bandwidth. That sounds low, but remember most smartphones have a limit to 2GB per month. With that transfer out
value, we can guess the average usage per file by GET request. 4281 / 451 = 9.49. 10 MB is relatively tiny for the average download, which leads me to believe that there have been many partial downloads.

So this is all free. How? You get a year for free with some minimal (yet quite generous) amount of transfer, storage and GET allowances. And even if this were not free, I think our usage is fair and will be priced accordingly. This was definitely the right way to go, versus hosting the audio files myself.

• Kindle Fire
• SOPA’s blackout & MegaUpload’s demise
• iBooks event

All that and more, on Episode 11 – Comfy Pants & Doom Clock.

The full story

On Friday, we had a little adventure which induced discrete delirium. That caused us to postpone until Saturday evening which of course lead into Sunday morning. The podcast was over one hour and fifty minutes originally, but that was with long pauses and some extra rambling. On Saturday, I decided to reconfigure the studio, which took an additional six hours. And then I had to edit the audio, because there were those Skype latency pauses and some overall odd-bits. So those two delays grew until Wednesday when I finally got the audio up.