comm page 15 - Dave's Blog

URI Addressable Text Adventure Games

This post is about creating a server side z-code interpreter that represents game progress in the URI. Try it with the game Lost Pig.

I enjoy working on URIs and have the mug to prove it. Along those lines I've combined thoughts on URIs with interactive fiction. I have a limited amount of experience with Inform which generates Z-Code so I'll focus on pieces written in that. Of course we can already have URIs identifying the Z-Code files themselves, but I want URIs to identify my place in a piece of interactive fiction. The proper way to do this would be to give Z-Code its own mimetype and associate with that mimetype the format of a fragment that would contain the save state of user's interactive fiction session. A user would install a browser plugin that would generate URIs containing the appropriate fragment while you play the IF piece and be able to load URIs identifying Z-Code files and load the save state that appears in the fragment.

But all of that would be a lot of work, so I made a server side version that approximates this. On the Web Frotz Interpreter page, enter the URI of a Z-Code file to start a game. Enter your commands into the input text box at the bottom and you get a new URI after every command. For example, here's the beginning of Zork. I'm running a slightly modified version of the Unix version of Frotz. Baf's Guide to the IF Archive has lists of IF games to try out.

There are two issues with this thought, the first being the security issues with running arbitrary z-code and the second is the practical URI length limit of about 2K in IE. From the Z-Code standard and the Frotz source it looks like 'save' and 'restore' are the only commands that could do anything interesting outside of the Z-Code virtual machine. As for the length-limit on URIs I'm not sure that much can be done about that. I'm using a base64 encoded copy of the compressed input stream in the URI now. Switching to the actual save state might be smaller after enough user input.

Identifying Vegetables with 20q Pocket Mind Reader

At the grocery store the other day Sarah and I attempted to find shallot for a recipe, but I can't tell the difference between shallot, sweet onions, yellow onions, etc. etc. We found something that we decided was the closest we'd find in the store and I believe we picked correctly because at checkout the cashier rang it up as shallot.

I think this could be a practical problem that the 20q Pocket Mind Reader should be able to solve: obtain the name of an unidentified object. When we got home I decided to test the 20q Pocket Mind Reader on shallot. Unfortunately, it told me I had an onion, but I think if these were designed for identifying unknown objects based solely on information you can obtain by looking at it, rather than requiring knowledge of seeds, where it grows, etc. it would do better. Or I could just ask someone who works at the grocery store.

Chumby will be cool, despite its name

I signed up for the pre-release beta and purchased a Chumby last year. Chumby looks like a cousin to a GPS unit. Its similar in size with a touch screen, but has WiFi, accelerometers, and is pillow like on the sides that aren't a screen. In practice its like an Internet alarm clock that shows you photos and videos off the Web. Its hackable in that Chumby Industries tells you about the various ways to run your own stuff on the Chumby, modifying the boot sequence (it runs Linux), turning on sshd, etc, etc. The Chumby forum too has lots of info from folks who have found interesting hacks for the device.

When you turn on the Chumby it downloads and runs the latest version of the Chumby software which lets you set alarms, play music, and display Flash widgets. The Chumby website lets anyone upload their own Flash widgets to share with the community. I tried my hand at creating one using Adobe's free Flash creation SDK but I don't know Flash and didn't have the patience to learn.

Currently my Chumby is set to wake me up at 8am on weekdays with music from ShoutCast and then displays traffic and weather. At 10am everyday it switches to showing me a slide-show of LolCats. At 11pm it switches to night mode where it displays the time in dark grey text on a black background at a reduced light level so as not to disturb me while I sleep.

I like the Chumby but I have two complaints. The first is that it forces me to learn flash in order to create anything cool rather than having a built-in Web browser or depending on a more Web friendly technology. The second complaint is about its name. At first I thought the name was stupid in a kind of silly way, but now that I'm used to the name it sounds vaguely dirty.

Schmap Licenses my Photos

I got a FlickrMail from Emma J. Williams a bit ago saying that they wanted to use two of my photos in their Schmap San Francisco Guide online travel guide. So now you can see two of my vacation photos on the Westfield San Francisco Shopping Center Schmap page and the Hotel Diva Schmap page.

I think its wonderful that digital cameras are at the point where I really don't have to know much about their workings to produce a photo that's reasonable looking. And its thanks to Flickr and searchable tags that Schmap could find my photos. Since my photos on Flickr are all licensed under a Creative Commons license named Attribution-Noncommercial-No Derivative Works 2.0 Generic which only applies to non-commercial uses, Schmap, which is advertisement supported, kindly asked me if they could use my photos. I agreed to their license which was human readable and included wonderful stuff like I get in place attribution and the license is only applicable while Schmap makes their guide freely available online.

Previously I've only heard of folks having their flickr photos used without their permission so I'm glad to know that's not always the case. Or perhaps this is just Schmap's clever method of getting me to blog about them.

LibraryThing Developers are Responsive

I use my recently added books feed from LibraryThing, a site I've mentioned before where you track, review, recommend, and share your books, and I put the recently added books on my page. I thought it might be nice to include the book covers so I suggested adding book covers to RSS feeds in LibraryThings 'Recommend Site Improvements' group. The next day I had a response from the founder and lead developer Tim Spalding who had started implementing the feature. I noticed a few bugs, reported them on the same thread, and he fixed them soon after. Fantastic! It makes me want to upgrade to a paying account.

Incidentally, if you notice the Ghost in the Shell book appear multiple times in my RSS feed its due to the previously mentioned iterative bug fixes. The same item appeared multiple times slightly differently with each bug fix and your RSS aggregator may have picked them up as distinct items.

Crossing Four Way Stops Fast and Searching Closed Caption MCE Videos: More Stolen Thoughts

More ideas stolen from me in the same vein as my stolen OpenID thoughts.

Fast Pedestrian Crossing on Four Way Stops. In college I didn't have a car and every weekend I had weekly poker with friends who lived nearby so I would end up waiting to cross from one corner of a traffic lit four way stop to the opposite corner. Waiting there in the cold gave me plenty of time to consider the fastest method of getting to the opposite corner of a four-way stop. My plan was to hit the pedestrian crossing button for both directions and travel on the first one available. This only seems like a bad choice if the pedestrian crossing signal travels clockwise or counter clockwise around the four way stop. In those two cases its better to take the later of the two pedestrian signal crossings, but I have yet to see those two patterns on a real life traffic stop. I decided recently to see if my plan was actually sound and looked up info on traffic signals. But the info didn't say much other than "its complicated" and "it depends" (I'm paraphrasing). Then I found some guy's analysis of this problem. So I'm done with this and I'll continue pressing both buttons and crossing on the first pedestrian signal. Incidentally on one such night when I was waiting to cross this intersection I heard a loud multi-click sound and realized that the woman in the SUV waiting to cross the intersection next to me had just locked her doors. I guess my thinking-about-crossing-the-street face is intimidating.

Windows Searching Windows Media Center Recorded TV's Closed Captions. An Ars-Technica article on a fancy DVR described one of the DVRs features: full text search over the subtitles of the recorded TV shows. I thought implementing this for Windows Media Center recorded TV shows and Windows Search would be an interesting project to learn about video files, and extending Windows Search. As it turns out though some guy, Stephen Toub implemented Windows Search over MCE closed captions already. Stephen Toub's article is very long and describes some other very interesting related projects including 'summarizing video files' which you may want to read.

Excercise Bike and Tacoma Screw Products

Sarah and I got an exercise bike on sale and when attempting to put it together found that it was missing a bag of about ten different screws. The manufacturer website said we could order a replacement bag for thirty dollars (!!) but since the instructions listed the various kinds of screws we needed I figured we could just go to a hardware store and buy them.

We started at Home Depot because I didn't know better. The screws are all listed in metric sizes which is apparently uncommon and a helpful senior worker forwarded us to McLendons whose stock was better but we were again redirected this time to Tacoma Screw Products.

Tacoma Screw Products is great! See them for your hardware needs first! The store has a back area with every kind of screw ever. I felt a little out of place as as all the customers looked like contractors. The employee who helped me explained the various options I had in screws as the bike instructions weren't as explicit as they could have been. In the end I bought all my screws for only one dollar (much better than $30!) and they all fit correctly.

IPv6 Roundup: Address Syntax on Windows

IPv6 address syntax consists of 8 groupings of colon delimited 16-bit hex values making up the 128-bit address. An optional double colon can replace any consecutive sequence of 0 valued hex values. For example the following is a valid IPv6 address: fe80::2c02:db79

Some IPv6 addresses aren't global and in those cases need a scope ID to describe their context. These get a '%' followed by the scope ID. For example the previous example with a scope ID of '8' would be: fe80::2c02:db79%8

IPv6 addresses in URIs may appear in the host section of a URI as long as they're enclosed by square brackets. For example: http://[fe80::2c02:db79]/. The RFC explicitly notes that there isn't a way to add a scope ID to the IPv6 address in a URI. However a draft document describes adding scope IDs to IPv6 addresses in URIs. The draft document uses the IPvFuture production from the URI RFC with a 'v1' to add a new hostname syntax and a '+' instead of a '%' for delimiting the scope id. For example: http://[v1.fe80::2c02:db79+8]/. However, this is still a draft document, not a final standard, and I don't know of any system that works this way.

In Windows XPSP2 the IPv6 stack is available but disabled by default. To enable the IPv6 stack, at a command prompt run 'netsh interface ipv6 install'. In Vista IPv6 is the on by default and cannot be turned off, while the IPv4 stack is optional and may be turned off by a command similar to the previous.

Once you have IPv6 on in your OS you can turn on IPv6 for IIS6 or just use IIS7. The address ::1 refers to the local machine.

In some places in Windows like UNC paths, IPv6 addresses aren't allowed. In those cases you can use a Vista DNS IPv6 hack that lives in the OS name resolution stack that transforms particularly crafted names into IPv6 addresses. Take your IPv6 address, replace the ':'s with '-'s and the '%' with an 's' and then append '.ipv6-literal.net' to the end. For example: fe80--2c02-db79s8.ipv6-literal.net. That name will resolve to the same example I've been using in Vista. This transformation occurs inside the system's local name resolution stack so no DNS servers are involved, although Microsoft does own the ipv6-literal.net domain name.

MSDN describes IPv6 addresses in URIs in Windows and I've described IPv6 addresses in URIs in IE7. File URIs in IE7 don't support IPv6 addresses. If you want to put a scope ID in a URI in IE7 you use a '%25' to delimit the scope ID and due to a bug you must have at least two digits in your scope ID. So, to take the previous example: http://[fe80::2c02:db79%2508]/. Note that its 08 rather than just 8.

Vegas and New Year

Two and half weeks ago Sarah and I went to Las Vegas where I got to see Jesse, Pat, Chris, and (briefly because he's some kind of big shot too busy for his friends now etc) Grib from college. They're mostly in San Jose and I hadn't seen them for a while so it was a lot of fun to hang out. We all stayed at the MGM which is a nice hotel with some good restaurants. In other Vegas related links, Sarah added Sarah's Las Vegas restaurant reviews to her reviews and Jesse has Jesse's Vegas photos up too.

Sarah and I saw the Blue Man Group (video from a concert) and the Price is Right Live Show. The Blue Man Group was very cool although the music was all rock with a heavy drum focus (not depicted in the videos I linked) which I got a little tired of. But despite that I really enjoyed the show, very funny and I totally recommend it. The Price is Right Live Show is like the regular show on TV except the recording is not televised and its not hosted by Bob Barker or Drew Carey. So folks from the audience are still called up to play the same games and really win prizes. It was advertised as hosted by Todd Newton, B-list game show host, but was instead hosted by JD Roberto who hosted such things as "Reality Remix" and the show "Are You Hot? The Search for America's Sexiest People". The showcase showdown included the 2008 version of my car and thankfully I wasn't picked to compete for that because, well I don't know where they bought the car, but I would have gotten the price very wrong. We sat right next to the stage for that show and had a good time.

For New Years Eve Sarah and I stayed in and watched the glitched Seattle Space Needle fireworks show from a safe distance. On New Years we went to a pot-luck at Todd's house and had a fun time. Todd's place is on the top of a hill and has a lovely view of Washington's snow-capped mountains.