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Showing posts from 2008

Tech Talk on Wii security model (and breaking it)

A very thorough talk describing the Nintendo Wii game console security model and the bugs and weaknesses that allowed the Wii to be compromised:
Console Hacking 2008: Wii Fail

In a nutshell, security is provided by an embedded ARM CPU that sits between the CPU and the IO devices, and handles all the IO. The two main flaws were (a) A bug in the code that compared security keys, such that it was possible to forge security keys, and (b) secret break-once-run-everywere information was stored un-encrypted in RAM, where it could be extracted using hardware modifications.

There's a nice table at the end of the presentation showing a number of recent consumer devices, what their security model was, and how long it took to break them.

The PS3 is the only console that's currently unbroken. The PS3's security model seems similar to the Xbox 360, but somewhat weaker. But it remains unbroken. This seems to due to the existence of an official PS3 Linux port, which means most Linux kernel ha…

Larrabee papers from SIGGRAPH Asia 2008

...as seen on the Beyond3D GPGPU forum, here are the presentations from the recent (December 12th 2008) "Beyond Programmable Shading" course:

SIGGRAPH Asia 2008: Parallel Computing for Graphics: Beyond Programmable Shading

There are good presentations from both GPU vendors and academics. My favorite presentations are the Intel ones on Larrabee, just because I'm so interested in that architecture:

Parallel Programming on Larrabee - describes the Larrabee fiber/task programming model.

Next-Generation Graphics on Larrabee - how Larrabee's standard renderer is structured, and how it can be extended / modified.

IBM / Sony missed a bet by not presenting here. That's too bad, because Cell sits between the ATI / NVIDIA parts and Larrabee in terms of programmability. And Cell's been available for long enough that there should be a number of interesting results to report.

Note to self: consider buying a PS3 and learning Cell programming, just to get ready for Larrabee. Heh, …

Fun with Git

This weekend I reorganize my home source code projects. I have a number of machines, and over the years each one had accumulated several small source-code projects. (Python scripts, toy games, things like that.) I wanted to put these projects under source code control. I also wanted to make sure they were backed-up. Most of these little projects are not ready to be published, so I didn't want to use one of the many web-based systems for source-code management.

After some research, I decided to use replicated git repositories.

I created a remote git repository on an Internet-facing machine, and then created local git repositories on each of my development machines. Now I can use git push and git pull to keep the repositories synchronized. I use git's built-in ssh transport, so the only thing I had to do on the Internet-facing-machine was make sure that the git executables were in the non-interactive-ssh-shell's path. (Which I did by adding them in my .bashrc file.)

Git's a…

Microsoft New Xbox Experience Avatars

Image
I just tried creating an avatar on Microsoft's new Xbox dashboard. As you can see (at least when the Microsoft server isn't being hammered) on the left, they provide a URL for displaying your current Avatar on a web page.

The character creation system is not too bad. In some ways it's more flexible than Nintendo's Mii (for example more hair styles and clothing), but in other ways it's more limited (less control over facial feature placement).

My avatar looks better on the Xbox than it does here -- they should consider sharpening the image. For example, the T-shirt my avatar is wearing has a thin-lined Xbox symbol.

I think they do a good job of avoiding the Uncanny Valley effect. I look forward to seeing how avatars end up being used in the Xbox world.

In othe Xbox-related news I'm enjoying playing Banjo Kazooie Nuts & Bolts with my son. All we have right now is the demo, but it's great fun for anyone who likes building things. It's replaced Cloning Clyd…

Internals of the Azul Systems Multi-core Java processor

I'm a big fan of CPU architectures. Here's a conversation between David Moon formerly of Symbolics Lisp Machines and Cliff Click Jr. of Azule Systems. They discuss details of both the Lisp Machine architecture and Azule's massively multi-core Java machine.

http://blogs.azulsystems.com/cliff/2008/11/a-brief-conversation-with-david-moon.html

The claim (from both Symbolics and Azule) is that adding just a few instructions to an ordinary RISC instruction set can make GC much faster. With so much code being run in Java these days I wonder if we'll see similar types of instructions added to mainstream architectures.

Can a comic strip make you more productive?

This one can:

XKCD: Someone is Wrong on the Internet

--- this comic's punchline has saved me at least an hour of a week since it came out. That's more than I've saved by learning Python. :-)

Next gen video console speculation suggests we aim low

The next generation of video game consoles should start in 2011. (Give or take a year). It takes about three years to develop a video game console, so work should be ramping up at all three video game manufacturers.

Nintendo's best course-of-action is pretty clear: Do a slightly souped-up Wii. Perhaps with lots of SD-RAM for downloadable games. Probably with low-end HD resolution graphics. Definately with an improved controller (for example with the recent gyroscope slice built in.)

Sony and Microsoft have to decide whether to aim high or copy Nintendo.

Today a strong rumor has it that Sony is polling developers to see what they think of a PlayStation 4 that is similar to a cost-reduced PlayStation 3 (same Cell, cheaper RAM, cheap launch price.)

http://forum.beyond3d.com/showthread.php?t=50037

That makes sense as Sony has had problems this generation due to the high launch cost of the PS3. The drawback of this scheme is that it does nothing to make the PS4 easy to program.

In the last f…

Woot! I'm 19th place in the ICFP 2008 Programming Contest

Team Blue Iris (that's me and my kids!) took 19th place, the top finish for a Python-based entry!

Check out the ICFP Programming Contest 2008 Video. The winning team list is given at 41:45.

Will Smart Phones replace PCs?

That's the question Dean Kent asks over at Real World Tech's forums. I replied briefly there, but thought it would make a good blog post as well.
I'm an Android developer, so I'm probably biased, but I think most people in the developed world will have a smart phone eventually, just as most people already have access to a PC and Internet connectivity.I think the ratio of phone / PC use will vary greatly depending upon the person's lifestyle. If you're a city-dwelling 20-something student you're going to be using your mobile phone a lot more than a 60-something suburban grandpa.This isn't because the grandpa's old fashioned, it's because the two people live in different environments and have different patterns of work and play.Will people stop using PCs? Of course not. At least, not most people. There are huge advantages to having a large screen and a decent keyboard and mouse. But I think people will start to think of their phone and their PC as …

Peter Moore on Xbox

Peter Moore on Xbox

I always liked Peter Moore, and I was sorry when he left Xbox for EA. He's given a very good interview on his time at Sega and Microsoft. (He ran the Xbox game group at Microsoft before moving on to Electronic Arts.) Lots of insight into the Xbox part of the game industry.

Here he is talking about Rare:
...and you know, Microsoft, we'd had a tough time getting Rare back – Perfect Dark Zero was a launch title and didn't do as well as Perfect Dark… but we were trying all kinds of classic Rare stuff and unfortunately I think the industry had past Rare by – it's a strong statement but what they were good at, new consumers didn't care about anymore, and it was tough because they were trying very hard - Chris and Tim Stamper were still there – to try and recreate the glory years of Rare, which is the reason Microsoft paid a lot of money for them and I spent a lot of time getting on a train to Twycross to meet them. Great people. But their skillsets were …

Pro tip: Try writing it yourself

Sometimes I need to get a feature into the project I'm working on, but the developer who owns the feature is too busy to implement it. A trick that seems to help unblock things is if I hack up an implementation of the feature myself and work with the owner to refine it.

This is only possible if you have an engineering culture that allows it, but luckily both Google and Microsoft cultures allow this, at least at certain times in the product lifecycle when the tree isn't frozen.

By implementing the feature myself, I'm (a) reducing risk, as we can see the feature sort of works, (b) making it much easier for the overworked feature owner to help me, as they only have to say "change these 3 things and you're good to go", rather than having to take the time to educate me on how to implement the feature, (c) getting a chance to implement the feature exactly the way I want it to work.

Now, I can think of a lot of situations where this approach won't work: at the end …

Tim Sweeney on the Twilight of the GPU

Ars Technica published an excellent interview with Tim Sweeney on the Twilight of the GPU. As the architect of the Unreal Engine series of game engines, Tim has almost certainly been disclosed on all the upcoming GPUs. Curiously he only talks about NVIDIA and Larrabee. Is ATI out of the race?

Anyway, Tim says a lot of sensible things:

Graphics APIs at the DX/OpenGL level are much less important than they were in the fixed-function-GPU era.DX9 was the last graphics API that really mattered. Now it's time to go back to software rasterization.It's OK if NVIDIA's next-gen GPU still has fixed-function hardware, as long as it doesn't get in the way of pure-software rendering. (ff hardware will be useful for getting high performance on legacy games and benchmarks.)Next-gen NVIDIA will be more Larrabee-like than current-gen NVIDIA.Next Gen programming language ought-to-be vectorized C++ for both CPU and GPU.Possibly the GPU and CPU will be the same chip on next-gen consoles.

The Future of Graphics APIs

The OpenGL 3.0 spec was released this week, just in time for SigGraph. It turns out to be a fairly minor update to OpenGL, little more than a codification of existing vendor extensions. While this disappoints OpenGL fans, it's probably the right thing to do. Standards tend to be best when they codify existing practice, rather than whey they try to invent new ideas.

What about the future? The fundamental forces are:

+ GPUs and CPUs are going to be on the same die
+ GPUs are becoming general purpose CPUs.
+ CPUs are going massively multicore

Once a GPU is a general purpose CPU, there's little reason to provide a standard all-encompasing rendering API. It's simpler and easier to give an OS and a C compiler, and a reference rendering pipeline. Then let the application writer customize the pipeline for their application.

The big unknown is whether any of the next-generation video game consoles will adopt the CPU-based-graphics approach. CPU-based graphics may not be cost competitive …

Mac Min HTPC take two

I just bought another Mac Mini to use as a HTPC (home theater PC). I tried this a year ago, but was not happy with the results. But since then I've become more comfortable with using OS X, so today I thought I'd try again.

Here's my quick setup notes:
I'm using a Mac Mini 1.83 Core 2 Duo with 1 GB of RAM. This is the cheapest Mac Mini that Apple currently sells. I thought about getting an AppleTV, but I think the Mini is easier to modify, has more CPU power for advanced codecs, and can be used as a kid's computer in the future, if I don't like using it as an HTPC. I also have dreams of writing a game for the Mini that uses Wiimotes. I think this would be easier to do on a Mini than an AppleTV, even though the AppleTV has a better GPU.I'm using "Plex" as for viewing problem movies, and I think it may end up becoming my main movie viewing program. It's the OSX version of Xbox Media Center. (Which is a semi-legal program for a hacked original Xbox.…

ICFP 2008 post-mortem

This year's ICFP contest was a traditional one: Write some code that solves an optimization problem with finite resources, debug it using sample data sets, send it in, and the judging team will run it on secret (presumably more difficult) data sets, and see whose program does the best. The problem was to create a control program for an idealized Martian rover that had to drive to home base while avoiding craters, boulders, and moving enemies.

I read the problem description at noon on Friday, but didn't have time to work on the contest until Saturday morning.

The first task was to choose a language. On the one hand, the strict time limit argued for an easy-to-hack "batteries included" language like Python, for which libraries, IDEs, and cross-platform runtime were all readily available. On the other hand, the requirement for high performance and ability to correctly handle unknown inputs argued for a type safe, compiled language like ML or O'Caml.

I spent a half an …

Getting ready for ICFP 2008

The rules for this year's ICFP contest have just been posted. Although the actual problem won't be posted until Friday July 11th, the rules themselves are interesting:
Your code will be run on a 1GB RAM 4GB swap 2GHz single-processor 32-bit AMD x86 Linux environment with no access to the Internet.You have to submit source code.You may optionally submit an executable as well (useful if for example you use a language that isn't one of the short list of languages provided by the contest organizers.)Teams are limited to 5 members or less.
I have mixed feelings about these rules. The good news is:
It should be possible for most interested parties to recreate the contest environment by using the contest-provided Live CD. A computer capable of running the contest could be purchased new for around $350.
It seems that the focus will be on writing code in the language of the contestant's choice, rather than writing code in the language of the contest organizer's choice. This was…

Network Attached Storage Notes

I just bought a Buffalo LinkStation Mini 500GB Networked Attached Storage (NAS) device. It's a very small fanless Linux file server with two 250 GB hard drives, 128 MB of RAM, a 266 MHz ARM CPU and a gigabit Ethernet port.
My reasons for buying a NASI wanted to provide a reliable backup of family photos and documents, and I was getting tired of burning CDs and DVDs.I wanted a small Linux-based server I could play with.My reason for buying the LinkStation MiniIt's fanless.It's tiny. Buffalo has a good reputation for NAS quality.There is a decent sized Buffalo NAS hacking community. Fry's had it on sale. :-)Setting it up Setup was very easy -- I unpacked the box, pluged everything in, and installed a CD of utility programs. The main feature of the utility program is that it helps find the IP address of the NAS. All the actual administration of the NAS is done via a Web UI.
To RAID or not to RAID The LinkStation Mini comes with two identical drives, initially set up as RAID…

I saw the original Spacewar! on a PDP-1 today

I went to the Computer History Museum today. I saw the Visual Storage exhibit, which is a collection of famous computers, the Babbage Difference Engine, which is a very elaborate reproduction of a never-actually-built Victorian era mechanical calculator, and the PDP-1 demo. This last demo was very special to me, because I finally got to play the original Spacewar! game, and meet and chat with Steve Russell, the main developer. (Perusing Wikipedia I now realize that Steve was also an early Lisp hacker. D'Oh!, I was going to ask a question about Lisp on the PDP-1, but I got distracted.)

There's a Java Spacewar! emulator, but it doesn't properly convey the look of the PDP-1 radar-scope-based display. The scope displays individual dots, 20,000 times per second. Each dot starts as a fuzzy bright blue-white dot, but then fades quickly to a dim yellow-green spot, which takes another 10 seconds to fade to black. This means that dim yell0w-green trails form behind the ships as they…

Thoughts on In-Flight Entertainment systems

I recently spent a lot of time using two different in-flight entertainment systems: one on Eva Air, and another on Virgin Atlantic. For people who haven't flown recently, I should explain that these systems consist of a touch-sensitive TV monitor combined with a remote-control-sized controller. The systems typically offer music, TV, movies, flight status, and video games.

I believe both systems were based on Linux. I saw the Eva system crash and reboot, and the Virgin Air system has a number of Linux freeware games.

The GUI frameworks were pretty weak -- both systems made poor use of the touch screen and had obvious graphical polish issues. The Virgin system was much higher resolution, and was 16:9 aspect ratio. I expect it was running on slightly higher-spec hardware.

Both systems worked pretty well for playing music and watching TV or movies. The media controls were pretty limited - neither system allowed seeking to a particular point in a movie, or even reliably fast forwarding. B…

Wii long term strategy

Here's a very long, quite good post on Nintendo's strategy with the Wii:

http://malstrom.50webs.com/birdman.html

The thesis is that the mainstream video game market arms race of every-more-complicated games ended up overshooting enough of the potential game market to allow an opening for simpler "down-market" games, and that Wii was able to exploit this opening. The article predicts that Nintendo will now move up-market, producing more complicated games over time, pushing PS3 and Xbox 360 into very up-market niches. Sort of how consoles took over from PC games.

OS X will hang if your VPN connection is flakey

OS X is by and large a good OS, but once you get past the sexy UI you find a lot of rough edges.

For example, this month I've been working remotely over a flakey DSL connection. I ran into a very frustrating problem: if you're using a PPTP-based VPN, and your network connection is poor quality, the whole Apple UI will frequently freeze up with the "Spinning beachball" cursor for minutes at a time.

Luckily for me the work-around is to reboot my DSL modem. But it seems like poor system design for the VPN packet performance to affect the UI of non-networked applications.

Yegge's rant on dynamic languages

Another superb rant by Steve Yegge on dynamic languages:

http://steve-yegge.blogspot.com/2008/05/dynamic-languages-strike-back.html

The comment section's good too -- especially the long comment by Dan Weinreb of Lisp / ITA software fame.

Steve's got the same problem some of my self-taught friends do (hi Bob, hi Jim!): he'll say something in a strongly opinionated way, without giving supporting evidence. I think that makes people think he doesn't know what he's talking about. So people tend to write him off. But if you talk with him, it almost always turns out his strong opinions are backed by some pretty deep experience and insight. I've learned to give Steve (and my self-taught friends) the benefit of the doubt.

Wow, TVs are complicated

Check out this teardown of a Sony OLED TV. It looks like Sony has a standardized architecture for their TVs, which makes sense, but which also means that some TVs have unused capabilities (such as a multi-core CPU powerful enough to run a web browser. I wish an enterprising hacker would figure out how to download code and run them on the TVs -- my understanding from reading Sony's GPL web site is that they already have Linux and busybox installed. Oh well, maybe GPL 3.0 will force Sony to make their TVs user-upgradable in the future.

It's significant that Sony's not using the Cell CPU in their TVs. That was part of the justification for spending so much on Cell. I assume this means that Cell's just not cost-effective for TVs.

Tom Forsyth on Larrabee

Tom Forsyth, who recently left RAD to work at Intel on the Larrabee project, has posted to his tech blog explaining that Larrabee is going to be primarily a traditional OpenGL/DirectX rasterizer, not some crazy raytracer:
Larrabee and Raytracing

Dusty Decks

Back in the '90s I had a home page where I posted some of my code hacks and articles. If you want to see what I was doing 10 years ago, check out:

Jack's Hacks

(Mostly Java and Anime. Both of which were leading-edge back then, but are kind of main-stream now.)

ThinLisp

Some notes on ThinLisp, a dialect of Lisp for real-time systems. Thin Lisp was written by Gensym Corporation in the '90s. The general idea is that you develop your program using a subset of Common Lisp, and then compile it into efficient C. Garbage collection is avoided by using object pools, arenas, and similar tricks familiar to advanced C programmers.

The current home of ThinLisp seems to be Vladimir Sedach's Code Page . Vladimir seems to have used it for "one small OpenGL" project before abandoning it. He seems to be happily hacking ParenScript (a Lisp to Javascript translator) these days.

The Scheme guys have similar, but more modest, sysems: Schelp, and PreScheme (part of Scheme48).

One year at Google!

Happy Anniversary to me! Google's automated HR script just emailed me its congratulations.

Although I miss my friends and former colleagues at Microsoft, and I miss the games industry, overall I'm still glad I made the switch. I'm enjoying the new work, and learning all the cool Google technologies. Now if only the stock price didn't keep going down. :-)

Some things I like:
Switching from Window to Macintosh. It took me six months to get used to the subtle differences, but as a user I'm just happier with the Mac. It's easier for me to use. Now, to be fair, at home I still maintain a Windows Vista machine for the excellent Windows Media Center, but for everything else I use the Mac.Better corporate politics. There seems to be less infighting between groups. And while my overall compensation is about the same as it was at Microsoft, the way it's managed and delivered makes it seem less competitive than MS. Perhaps it's an illusion, but it feels better.Better…

Insomniac Games Shares Technology

One very nice habit of Western game companies is that many of them share their technical knowledge with competitors. Insomniac Games is a very good third party console game developer that has concentrated mostly on the PlayStation platform. Their recent games include the shooter "Resistance Fall of Man" and the action platform Rachet and Clank series.

At this year's GDC they announced the "Nocturnal" initiative. It's not a whole game engine, but rather a collection of useful utilities. Things like logging code, C++ object serialization, and a cross-platform performance monitor. Some of the utilities are Playstation 3 specific, but most are applicable to any modern game platform.

Much of this code would be right at home in a "Game Gems" book, but it's even better to have it freely available, on the web, with a BSD-style license. Good for you Insomniac!

Insomniac also publishes technical papers in a GDC-presentation-like format on their Game R &a…

TaxCut 2007 vs. Case-sensitive file systems

OS X allows you to format your file system as case-insensitive (the default) or case sensitive (like Linux.) I use case-sensitive, to simplify porting and working on Linux software.

Unfortunately, H&R Block's TaxCut 2008 program won't work if installed on a case-sensitive file system. It fails because it can't find files, probably due to differences between the case of the file name used by the programmer and the actual case of the file name on disk.

A work-around is to use the Disk Utility program to create a case-insensitive image, and install Tax Cut on the image. I used a 600 MB image, so that I can store all my tax forms there too, and eventually burn the whole thing to CD to archive it.

Tim Sweeney Too - DX 10 last relevant graphics API

A good, three-part interview with Tim Sweeney (the other FPS graphics guru):

Part 1: http://www.tgdaily.com/content/view/36390/118/
Part 2: http://www.tgdaily.com/content/view/36410/118/
Part 3: http://www.tgdaily.com/content/view/36436/118/

His main thesis is that soon GPUs will be come so programmable that you won't bother using a standard Graphics API to program them. You'll just fire up a C compiler.

I think he's right.

Carmack speaks on real next-gen graphics

John Carmack is experimenting with a "sparse octree" data structure for accelerating 3D graphics rendering:

http://www.pcper.com/article.php?aid=532&type=overview

Best quote:

"The direction that everybody is looking at for next generation, both console and eventual graphics card stuff, is a "sea of processors" model, typified by Larrabee or enhanced CUDA and things like that, and everybody is sort of waving their hands and talking about “oh we’ll do wonderful things with all this” but there is very little in the way of real proof-of-concept work going on. There’s no one showing the demo of like, here this is what games are going to look like on the next generation when we have 10x more processing power - nothing compelling has actually been demonstrated and everyone is busy making these multi-billion dollar decisions about what things are going to be like 5 years from now in the gaming world. I have a direction in mind with this but until everybody can actu…

ForumWarz - a game about the web forum culture

This is an interesting role-playing-game set in current-day web forum culture:

http://www.forumwarz.com/

It's somewhat not-safe-for-work, and the humor is pretty low-brow. But what's neat is that you play it through your browser, and it recreates the look-and-feel of web forum culture perfectly. It wouldn't surprise me if the authors just captured the HTML for various real-world forums to create the resources for the game. (Or alternately, created their own fictional forums using web tools, and then captured the HTML from those fictional forums.)

The actual game didn't hold my interest for very long, but it's free and it's fun for a few days.

Good web site for following the Microsoft / Yahoo Merger

Silicon Alley Insider seems to have the best coverage of the Microsoft / Yahoo Merger.

But for the grumpy inside-Microsoft point-of-view you can't beatMini-Microsoft .

We write for posterity

The Google Analytics numbers for this blog are dismal. (Hi Mom! Hi Friends!) I think it's because right now I don't have much to say that's both unique and interesting. Partly this is because so much of my life is off limits: I don't want to talk about the joys & cares of raising a family, and I musn't talk about the joys & cares of raising a new product. What's left are comments on the general state of the web, and essays on general topics like this one.

Why write then, and who am I writing for? I write because something inside me compells me to, and because it helps me think to get my ideas down in written form. Who do I write for? From my Analytics numbers it's clear that I'm writing primarily for search engines (Hi Googlebot!) rather than people. And that's something interesting to think about: Baring a world-wide disaster or cultural revoloution, what I write today will persist for thousands and probably even millions of years, and wi…

Hey, Paul Graham's arc programming language is out!

I just noticed (while reading the 4chan prog forum for the first time) that Paul Graham has put up a web site for his minimal Lisp language Arc:

http://arclanguage.org/

The language looks like a nice quiet Scheme-like Lisp dialect. And it has a nice tutorial, as you would expect from a Paul Graham language.

3dMark price/performance charts

3DMark is a GPU/CPU benchmark used by PC gamers to measure system performance. Here are some great charts showing
What GPU/CPU/RAM/OS/Screen size gamers have, and how it's changed over timeThe best bang-per-buck for GPUs and CPUsMy home computer system is very weak compared to these charts, except in one dimension, which is that my 1600 x 1200 display puts me in the top 10% of gamers. Woot!

While many people (myself included) have switched to laptops and/or all-in-ones, if you're planning on building a new desktop, check out the Ars Technica system guide. The guide does a good job of speccing out a "Budget Box", a "Hot Rod", and a "God Box", and it's updated every quarter.

Languages that look interesting

Currently I'm reading up on the following computer languages:

Python - fun, easy to learn, batteries included
Boo - fun like Python, but with macros and type declarations so that it can run fast.
Erlang - very brief code. I'm impressed by how concise the Wings3D source code is.
Typed Scheme - Scheme with type checking. (Could in theory run fast.)

I may try implementing my old "Dandy" game in these languages to see how they feel.

Darwin Ports issue with "patch"

Ever since I've upgraded to Apple Macintosh OS X 10.5 Leopard, I've run into problems using the Darwinports "port" command to install new software.

The problem is that for some reason the version of GNU "patch" that I have installed in /usr/bin/patch is version 2.5.8, and it doesn't operate the way that Darwin ports expects. A typical error message is:

---> Applying patches to erlang
Error: Target org.macports.patch returned: shell command " cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_lang_erlang/work/erlang-R12B-0" && patch -p0 < '/opt/local/var/macports/sources/rsync.macports.org/release/ports/lang/erlang/files/patch-toolbar.erl'" returned error 2
Command output: Get file lib/toolbar/src/toolbar.erl from Perforce with lock? [y]
Perforce client error:
Connect to server failed; check $P4PORT.
TCP connect to perforce failed.
perforce: host unknown.
patch…

Web scraping in Java, F#, Python, and not Lisp

Yesterday I wrote a web scraper. A web scraper is a program that crawls over a set of web pages, following links and collecting data. Another name for this kind of program is a "spider", because it "crawls" the web.

In the past I've written scrapers in Java and F#, with good results. But yesterday, when I wanted to write a new scraper, I though I'd try using a dynamically-typed language instead.

What's a dynamically-typed language you ask? Well, computer languages can generally be divided into two camps, depending on whether they make you declare the type of data that can be stored in a variable or not. Declaring the type up front can make the program run faster, but it's more work for the developer. Java and F#, the languages I previously used to write a web scraper, are statically typed languages, although F# uses type inference so you don't actually have to declare types very often -- the computer figures it out for you.

In order to scrape HTML…