WikiPad 1.1 has been approved for sale in the App Store. This version includes full support for the iPad. If you’ve already purchased WikiPad for iPhone, all you need to do is download the free update and you’ll be ready to go!
If you’re wondering how to keep your iPad and iPhone copies of WikiPad in sync, don’t worry. Sync support is coming soon. Stay tuned!
(Caution: extremely technical post ahead.)
I’m looking for a way to provide WikiPad with the ability to sync between iPhone, iPad, desktop and possibly other mobile platforms. I’d also like reuse the code in my future apps, and make it available to other developers, probably under an Apache 2.0 license.
I’m thinking a WebDAV-based solution might be best, because then users could sync to the cloud via MobileMe, or to a local desktop machine running a WebDAV server.
WikiPad’s current schema is quite simple:
CREATE TABLE page_store (name TEXT, contents TEXT);
but future apps might have more complicated, and more relational database-type schemas. It seems like what I want is a way to record all the transformations to the database since the last sync, and then upload a file containing that information. Other instances of the app could then download that file and replay the actions to synchronize their databases with the changes.
Suggested course of action:
Peter Robinett has suggested basing the sync on a distributed version control system, such as GIT or Mercurial, since distributed version control systems are designed to deal with multiple concurrent changes to the source base. Seems technically feasible, but both GIT and Mercurial are GPL, which makes them incompatible with closed-source commercial apps (of which WikiPad is one).
Blame Andy Hunt.
Back in late 2001, I attended Jerry Weinberg’s Problem Solving Leadership workshop with Andy, and during a break we got around to talking about what apps we had on our Palm V organizers. Andy said that he wished somebody would write a wiki for the Palm.
“That’s a stupid idea,” I said. “Wikis are about sharing information. What would the point of a wiki be if the information were all locked up inside a single device?”
Andy shrugged and the conversation went elsewhere. But after a few months, the idea of a personal wiki started making more and more sense to me. It would be a relatively simple Palm OS application to write. So on a plane flight in August 2002 (ironically on the way to Jerry Weinberg’s Change Shop workshop), I wrote the initial version of WikiPad for the Palm. I still have the notes I took that week on WikiPad to this day.
I used WikiPad for Palm happily for many years, first on my Palm V, and then on a couple of Palm Treos. Once Apple released the iPhone SDK, I created an iPhone version of WikiPad for my own use almost immediately. And now, after much polishing, I present the first public release of WikiPad for iPhone. Use it in good health.
[Update 4/9/2010] WikiPad for iPad is coming soon.
Recently, Blogger announced that they were going to stop supporting blogs published via FTP on third-party sites, such as this one. So, once again it’s time to change blogging tools. WordPress has been getting a lot of buzz lately, so I thought I’d give that a whirl.
The WordPress installation was not a problem. But the version of MySQL on my host was too old, which meant I had to migrate my site to a newer box, which broke email, and meant I had to reinstall spamassassin. There’s a name for starting out wanting to change blogging tools and ending up reinstalling your spam filter. It’s called yak shaving.
I’ve shaved yaks before, of course, but this time was special. I hadn’t even wanted to change blogging platforms in the first place — I’d been forced to by Blogger’s change. That means that this yak was all hair.
Let me emphasize that the actual WordPress installation process was quick and painless. When I tried to install on my old host, the installer immediately noticed that my version of MySQL wasn’t up to date and refused to run. Once I had a suitable host, the 5-minute install worked like a charm. And importing all my old Blogger posts was just a matter of a few clicks in the “Tools” section of the WordPress dashboard. Best of all, things to some advice from this article, I’ve even managed to preserve all my old URLs.
So I’m back up and running with a shiny new blogging tool, with only a few hours of downtime. Maybe the shiny tool means I’ll blog more often. Stay tuned.
I’ve always been fascinated by GPS. I got my first GPS unit in 1997. Stacy and I had just gone on a hike with another couple, and they took a wrong turn and started arguing with each other in Czech. So I got a Garmin GPS II. It didn’t have maps; it just recorded a breadcrumb trail of your position, and let you enter waypoints on the map. But one cool feature it did have was a display of the GPS satellites’ positions in the sky relative to your current location. You could watch specific satellites rise, transit and set. This amazed me, but the truth is even more amazing than that.
A lot of people think GPS works by triangulation, but it doesn’t. It uses trilateration. Triangulation is measuring the angle to or from several known locations to your location. Trilateration is measuring the distance. You know the location of each GPS satellite because each satellite is broadcasting its precise orbital parameters, along with an extremely precise time signal. By taking the difference between the timestamp that the satellite broadcast and the time at your location and multiplying by the speed of light, you can draw a sphere around the satellite, the surface of which contains your location. Doing this for a second satellite gives you a second sphere, narrowing your location to somewhere the surfaces of the two spheres intersect. A third satellite should narrow your position down to a single point, but because of uncertainty in the signal, you typically get more of a blob. Typically, you need 3 satellites to get a good 2D fix (lattitude & longitude), but 4 or more to get a good 3D fix (lattitude, longitude and altitude).
Now consider this. In order to figure your location to within 10 meters, you need to know the satellite’s position even more precisely than that. Anecdotal reports (by a guy sitting at the next table at No-Name) put the precision of the satellite’s at under half a meter. Now, I rarely know where I am to within half a meter, and I’m not hurtling through space at 4 km/sec, having been shot there atop a rocket in the first place.
I’ve always wondered about the details of the GPS signal, and in particular the satellite orbits, which my more modern Bluetooth GPS doesn’t support. If only there were some way to decode the raw satellite signal, so I could play with it…
I’m in Chicago from July 13th through August 17th for iO Chicago’s month-long summer improv intensive.
Excecpt for this weekend, when I’m in Champaign-Urbana for the Second Worldwide Four-Square Invitational Conference (actually a multi-class reunion for University High School). I’ll be here in Champaign until the afternoon of Sunday the 20th of July.
Today my life resembles George Carlin’s “A Place for My Stuff” routine, as I had to pack up a subset of the stuff I took to Chicago, and bring it to Champaign. “The third version of my house,” as he calls it.
If you’re in Champaign or Chicago, and would like to get together, drop me an email.
So, it’s been a few months since I went to see the shuttle launch.
It was okay.
I guess you could sum up my feelings with that Peggy Lee song “Is That All There Is?” The reason that I went to see the shuttle launch is because of the essay Penn Jillette wrote about it in Penn and Teller’s “How to Play in Traffic”.
“It’s 3.7 miles away, and your looking at this flame and the flame is far away and it’s brighter than watching an arc welder from across a room[….] The fluffy smoke clouds of the angels of exploration spill out of your field of vision. They spill out of your peripheral vision.”
“You don’t exactly hear it at first, it almost knocks you over. It’s the loudest most wonderful sound you’ve ever heard. […] You can’t really hear it. It’s too loud to hear. It’s wonderful deep and low. It’s the bottom.”
“This is a real explosion and it’s controlled and it’s doing nothing but good and it makes your unbuttoned shirt flap around your arms. It’s beyond sound,it’s wind. It’s a man-made hurricane.”
The key point there being, “3.7 miles away”. In the VIP section. I was in closer to 7 miles away, along the NASA Causeway, in the closest section open to to the general public. From there, the Shuttle is a tiny speck without binoculars, and the sound of the launch, when it hits you, is reminiscent of the sound of distant thunder in the midwest. And with the low clouds, the whole show was over in matter of seconds. I could tell you more, but just watch the movie. That’s pretty much what I saw and heard, and I’m nowhere near as good at words as Penn.
Next time, I’m bringing binoculars.
I’m doing a little spring cleaning of my website, and as part of that, I’ve restarted my blog. This time I’m using Blogger. For those of you keeping score at home, previous attempts have used:
But, hey, this time for sure!