Nick Barkas

Long overdue update

Wed, 24 Jun 2009 23:39:20 GMT

Hello world. I am such an unreliable blogger. I've finally got around to putting together a little post about what's new in my life, though.

First of all, I have just started working on my master's thesis with the PoGOLite project. PoGOLite is an instrument that will measure the polarization of gamma rays from some interesting objects in space like the Crab Nebula and the Cygnus X-1 black hole. The instrument will be carried to about 40km up in the stratosphere by a balloon, and the first mission is scheduled to fly in August of 2010 from Kiruna, in the far north of Sweden. My particular small piece of this big project will involve working with some computer simulations using Geant 4. Using an existing model for the instrument, I will see what it measures for simulated photons from the Crab pulsar with various different degrees and angles of polarization. We'll create a database of simulated readings, and compare the data gathered from the real observations next summer against this database.

I'm quite happy about this project. I have loved astronomy since I was a little kid, and it's exciting to be involved in a real experiment. I'm looking forward to my own work potentially making some contribution. And as an added bonus, PoGOLite-themed postage stamps were issued in Sweden this year. I bought a few, so if I send you a postcard any time soon you might get to see one of these stamps personally.

In other news, I became a FreeBSD src committer not too long ago. This came about mostly as a result of my project during last year's Google Summer of Code. It is always tough to find time these days for working on open source stuff, but it's really nice to get to personally commit some of the code I have been able to write. I hope in the future to do some more work with UFS, possibly related to on-disk directory indexing.

And for something a little less nerdy, earlier this month I went to Gotland with Emma and our friends Heydar and Helen. Helen is from the island. Our friend Antoine also joined us after we were already there a couple of days. I just uploaded some of my photos to Flickr here. It's a nice place to visit, and one of the few places in Sweden where people surf. Östersjön (aka the Baltic Sea) doesn't have much in the way of waves, but sometimes the wind brings a few to Gotland. Hopefully I can go back one of these days and try to find some of those little waves.

Dirhash Low Memory Event Handling Patch

Sat, 12 Jul 2008 12:56:33 GMT

I now have some working code for my dirhash dynamic memory allocation Google Summer of Code project. It is currently being reviewed and needs further testing, but if you're feeling brave you can grab a patch against HEAD from my project page on the FreeBSD wiki.

What the new code does is add an event handler for vm_lowmem events. When one of these events happens, the kernel will try to delete dirhashes that have not been used for DH_RECLAIMAGE seconds. This is currently set to five seconds, but I have no idea if this will be an optimal time. A bit of benchmarking and testing will be necessary to sort that out. If all dirhashes have been used more recently than DH_RECLAIMAGE, instead the first unlocked dirhash on the TAILQ list used to keep track of them all will be deleted. Due to how the existing dirhash code organizes this list based on a scoring system, the first hash on the list should be a mix of the the least recently used and least frequently used.

If my code turns out to work as it should, then the default maximum memory for dirhash can be safely increased quite a bit. If the system has plenty of spare memory, then lots will be available for dirhashes. Then if the system becomes low on memory, some of this dirhash memory will automatically be freed up for use by whatever else needs it. Hopefully we'll see some performance improvements overall on systems with lots of memory that need to deal with large directories, but I haven't done the benchmarks yet.

Back Home in Stockholm

Sat, 12 Jul 2008 12:29:16 GMT

I returned home to Stockholm nearly two weeks ago, but haven't managed to find time to post anything since then. It's good to be home. I missed Emma a great deal and it has been wonderful to get to spend time with her again. The weather is quite nice, though we've had some humid and rainy days. I don't mind those so much though. The amount of sunlight is amazing! In the middle of the night the sky is still bright if you look north, and it's pretty much fully daylight here by around three in the morning.

I have a new apartment in Lappkärrsberget, or Lappis, a big student neighborhood north of Stockholm University. Yesterday was my second trip to Ikea to finish getting furniture for the new place. The room is a little smaller than the one I had previously, but much cheaper and quite cute. Emma and my good friend Heydar also live in Lappis so I can visit them or they me with just a couple of minutes walk instead of a 30-45 minute trip by bike or Tunnelbana. I have a road right out my window but it is usually fairly quiet, and there are lots of trees to look at. A bunch of cows have been brought in to a nearby field, so I get to listen to them mooing too! I'll take some pictures of the new apartment soon.

My sister and her husband came to visit from Washington DC shortly after I returned from SF. They spent a couple of days with me in Stockholm and that was pretty fun. They then went on to Helsinki, St. Petersburg, and Tallinn before they come back here in a sort of loop around the Baltic Sea. Emma and I are getting on the ferry to Tallinn tonight to meet up with them and we'll all come back to Stockholm together in a couple of days. I am excited for the trip. I love the big Baltic ferries/party boats. And I've never been to Estonia, nor did I ever even think about it before I came to Sweden.

Oh, yesterday I bought an iPhone, now that they are finally available legitimately in Sweden. It's quite cool, though it was annoying how I couldn't get iTunes to connect to Apple's servers for several hours yesterday to finish setting the thing up. I love new toys. I'm now locked into a two year abonnemang with Telia, so I guess I will be staying in Sweden for awhile!

Dirhash memory allocation update

Wed, 11 Jun 2008 08:55:09 GMT

The Summer of Code officially started a couple of weeks ago, so I've been getting started on my project. I've not written any actual code yet, but have been busy with other aspects of the project. First of all I have been reading a bit of documentation and code relevant to dirhash itself and FreeBSD memory management. I have a lot to learn, especially about the memory stuff. The two approaches I am looking at, mentioned in the USENIX paper by Ian Dowse and David Malone (my SoC mentor), are to either use the buffer cache for dirhash's memory so the VM can take care of providing memory as it is available, or to use a method for allocating memory where the kernel can signal for some to be freed in low memory situations, perhaps using the slab allocator.

I have also been learning a little bit about Perforce, the version control system used by FreeBSD for experimental projects. I have not used Perforce before this, and it is a bit different from the VCSs I've used before (CVS and Subversion). Also, I have done a bit of experimentation with the current dirhash implementation just to be sure that it can free memory it no longer needs. This was just a simple test where I created a directory with a couple of million entries, checked the vfs.ufs.dirhash_mem sysctl, removed the directory, then checked vfs.ufs.dirhash_mem again to make sure the memory used had decreased. It had. Finally, I sent off a brief proposal to do a talk about this project at EuroBSDCon 2008. Obviously I don't have much to create a talk with yet, but I should by the end of the summer. Plus, the second day of EuroBSDCon this year happens to fall on my birthday, and I think hanging out with fellow BSD nerds in France could be a fun birthday activity :)

New photos, Eurovision song contest

Sun, 25 May 2008 01:14:27 GMT

The day after I arrived in San Francisco was Bay to Breakers, so I immediately had an opportunity to take a lot of photos. Here are some of them. I avoided photographing the many naked people there were wandering around, so those should all be safe for work. I also took a few other photos while walking and biking around the city. San Francisco is a pretty nice looking place.

Then, today was the finals for the Eurovision song contest. I wish I could have been in Sweden watching it with Emma and some friends, but I could at least get a live stream of it over the Internet. It was pretty entertaining. Dima Bilan from Russia won, but I liked other songs better, like the one from Iceland's Euroband. Sweden's entry from Charlotte Perelli sadly did not do very well in the voting. My favorite though was Baila el Chiki Chiki from Rodolfo Chikilicuatre in Spain:

Very amusing song. None of these videos are from the actual final contest performances because I couldn't find those on youtube yet. The whole contest can be streamed though, like the finals here.

In San Francisco

Sun, 18 May 2008 05:16:32 GMT

Today I made the long journey from Stockholm to San Francisco. I was a day later than intended, because yesterday I overslept massively and missed my flight--something that I have been doing far too often lately. I am now extremely tired because I got up about twenty-five hours ago and have spent much of that time in transit.

I bought some duty free akvavit in Stockholm and they tried to take it away from me in London. The airport security guy at Heathrow told me that Sweden is not part of the EU, and thus booze I bought there was not eligible to be duty free. I argued with him that in fact Sweden absolutely is part of the EU. He ultimately talked to his manager and they decided to let me through with my tasty akvavit anyway. Very weird.

My new flat is quite nice. It is somewhat furnished, but I need to make an Ikea trip to get the stuff it doesn't have yet. That will also give me an opportunity to buy some Swedish food that I will no longer be able to find readily at supermarkets. I'm living in the inner Richmond, which is not a neighborhood I've lived in before, so I'm going to need to explore to figure out where stuff is. Also, I'd really like to find a bike to ride. It would be great to be able to ride to work rather than take the bus.

I already miss Emma and feel homesick for Sweden. Riding BART into the city I felt like I've seen everything before, but it's become kind of foreign. It is strange to return to one's own country and not feel like it is home anymore. But I expect that I'll be keeping myself very busy in the coming weeks so the homesickness shouldn't be too bad.

Trip to San Francisco

Tue, 22 Apr 2008 20:34:35 GMT

My employer is having me come over to the states for six weeks starting next month to do some extra work while I have time off from classes. I'll be in San Francisco from the 16th of May until the 28th of June. Get in touch with me if you want to hang out!

Switch to Movable Type

Sat, 29 Mar 2008 17:50:41 GMT

I've reworked my site once again. This time I'm using Movable Type to power everything. I've imported old entries I used to have on a now-defunct Typo powered blog, as well as more recent posts from my LiveJournal.

Norrland

Thu, 27 Mar 2008 01:25:38 GMT

Emma and I spent the last week in northern Sweden. We took the train (which was on time, comfortable, and from an easy-to-reach station, all unlike flying) to Härnösand, where she is from. From there we also took a day trip by car to Umeå. I had a nice time. I met her parents and some more of her friends. It was Easter so we used that as an excuse to eat lots of candy. Sadly the mild winter has affected norrland too, so there wasn't a lot of snow in Härnösand and Umeå, but there was certainly more than I've seen in Stockholm. It also got rather cold at times. I believe down to -14°C one night, which seems quite cold considering it is now spring. I took quite a few photos. Here are some of the ones I've uploaded to Flickr:

Air travel is so lame

Sat, 15 Mar 2008 17:09:14 GMT

Well, I'm not in Kiruna. Thursday night my friends and I made our way to Arlanda airport to catch a quick flight to Kiruna. The flight was delayed, and some time after our supposed new departure time, someone who worked for the airline came and told us that there was a problem with radar or the radio in Kiruna, so no planes could land. She gave no estimate on when we'd get to leave. Several hours passed. Someone else finally came out around midnight or so and told us that they would not be able to fly tonight, and there would be another plane that could take us at 6 o'clock the following morning. After some deliberation, Emma and I decided that sleeping in the airport and having our time in Kiruna cut down quite a bit was a bunch of bullshit, and we were going to go home. Heydar, Lisa, and Antoine all decided they'd stick it out and take the morning flight. Emma and I got the airline to remove our luggage from the plane, collected it, bid our friends farewell as they looked for some nice benches to sleep on for a few hours, and took a rather expensive taxi ride back home.

I am not at all fond of flying anymore. Being on planes itself can occasionally be fun despite the cramped conditions and unpleasant airplane air, but all the crap about getting to inconveniently located airports, going through check-in and security queues, waiting for delayed flights, etc. has become so old. I am thinking I should try to only resort to air travel when I'm going to other continents. Short flights are quick and usually cheaper than trains, but I don't think all this cheap air travel we have nowadays is really worth the other costs it brings about. The cost to passengers in the rather low quality of service airlines can afford to provide makes the experience of flying not fun, and with what must be very low profit margins I don't see how airlines can afford to properly pay their employees. The environmental impact of so much air travel can't be good, either.

I am disappointed that I am missing out on cross country skiing, riding a snowmobile to the ice hotel, and going for a little trip by dog sled. I wanted to see some real snow and aurora borealis and sit in a sauna. I guess this will all have to wait for next winter now. But, in a couple of days Emma and I are going to take another trip. We're going to be visiting Härnösand for about a week, the town she is from, and possibly taking a little day trip up to Umeå as well. These places are in norrland so there will probably be a little snow up there too, but not the huge amounts that there likely still is in Kiruna.

On an unrelated note, I am currently experimenting with growing a beard. It is very strange.

Skola, resa, och flickvän!

Mon, 25 Feb 2008 21:30:12 GMT

It's been awhile since I've posted much about what I'm up to. Life has been busy. After returning from my little trip to the US I started back into class right away. Currently I am taking courses in parallel computing, numerical differential equations (that one is mostly about finite volume methods for hyperbolic PDEs), and astrophysics. I'll be finished with astrophysics next month and in late March will be starting an advanced numerical analysis course. For the first couple of weeks of the semester I was slacking off a bit, but no time for that anymore. School is seriously kicking my ass now.

Next month during our spring/Easter break from classes I will be taking a trip with some folks up to Kiruna. I'm hoping to see some aurora borealis, an ice hotel, real snow (we had hardly any in Stockholm this winter), sitting in a sauna then jumping into that snow, cross country skiing, and perhaps going for some rides on a dog sled and/or snowmobile. I am really looking forward to this trip.

Other even more exciting news is that I now have a girlfriend! For the past few weeks I've been seeing a nice Swedish girl named Emma. She is awesome. I am quite happy.

Caucus time!

Sat, 09 Feb 2008 12:57:45 GMT

Non-Americans, non-Washingtonians, and Republicans can safely ignore this post.

When I left San Francisco I decided to be a resident of Washington state again, so I'm voting with you Washingtonians out there in this primary. However, I didn't really know that voting in the Democratic primary in Washington is meaningless (correct me if I'm wrong about that) until today. I've already voted absentee. I wonder why they even send Democratic absentee ballots to people overseas if our votes don't mean anything. I wasted 10kr. on postage!

Anyway, please please go caucus today. I wish I could be there. And if you want my opinion on the matter, I think you ought to support Senator Obama.

Stockholm rail map for iPod Touch and iPhone

Wed, 06 Feb 2008 17:00:12 GMT

I found this cool Berlin subway map for iPhone/iPod Touch that Randy Reddig made. It was inspired by an NYC subway map by Khoi Vinh, and in turn inspired me to make one for SL's tunnelbana (metro/subway), lokalbanor (local train), and pendeltåg (commuter train) map of Stockholm. Download it here, unzip, and take a look at the readme.txt file to see how to put it on your iPod or iPhone.

I'd like to make one of these for SL's bus system too, but have not yet found a suitable map to chop up. The best Stockholm city bus map I've found doesn't have night busses on it. Most of the time when I'm taking the bus it's only because the t-bana is closed for the night, so having the night bus routes would be really useful!

I am also a Lemming

Tue, 05 Feb 2008 15:18:35 GMT

I have given in. I am on Facebook now. I can't seem to figure out how to find many people to add as friends, and I don't want to give them my whole address book. So I guess look at my profile and me as a friend on there if you want.

I'm a Photographer!

Sat, 26 Jan 2008 16:58:27 GMT

One of my photos of Stockholm was found on Flickr and now has been added to the most recent version of the Schmap Stockholm Guide. See it here by mousing over the entry for Norrmalm in the list of neighborhoods.

London -> US

Mon, 24 Dec 2007 10:48:18 GMT

I'm currently at Heathrow airport, waiting for a delayed flight to Chicago. I'm guessing the delay is related to the massive amount of fog in London today. I don't want to pay for wifi here so I'll probably not post this for awhile. I've heard more American accents around me at this airport than I have since I was still in the US, I think. Apparently a lot of Americans go to London.

I was unexpectedly upgraded to business class! I got to go through fast track security, which meant very short lines. I'm excited. I think I will get a bed on the plane.

I have been in London only since early yesterday afternoon. I dropped off my things at Emma's house (old friend from way back when I lived on San Juan Island), then wandered around the city a little bit. I took some photos that I will upload to Flickr at some point in the near future.

When I arrived at Stansted airport I did not hear as many people speaking English as expected. Emma's neighborhood has a great many signs in Arabic or Farsi too, as well as restaurants advertising halal food. Pretty much everything is in Swedish or English in Stockholm; maybe it's different in the suburbs where I hear many more immigrants live.

Oxford Circus is utterly insane three days before Christmas. So many people shopping. I saw some cool decorations, and did some shopping myself. Didn't buy much though due to things being rather expensive here.

London is much dirtier than Stockholm. This reminded me that Stockholm is a really clean city.

Oh man, so many freaking CCTV cameras. Lots of "If you see something suspicious, tell the authorities" signs in the underground too. I also had to actually go through customs even though I came from an EU country, because Great Britian is not in the Schengen area (I think the UK and perhaps the Republic of Ireland are the only EU/EEA countries that haven't signed Schengen and do not plan to implement it). Britain sure is paranoid. Kind of like the US.

I don't remember tube carriages being so strange. They have a rad shape. Kind of low ceilings though, presumably because the old tunnels weren't made very big. I was glad I'm not tall.

So some time and a lot of miles have passed. I'm now in Chicago. My flight was very nice. Business class certainly makes an eight hour flight much nicer. I did have a bed. Wish I would have slept in it rather than watching movies and Top Gear the whole time. The flight ended up being nearly three hours late to depart, and as a result I missed my connection in Chicago. I have been at O'Hare airport now so far for over seven hours. I slept on a bench a little bit, and am now waiting to board a new flight... to St. Louis. There I transfer and finally get to Seattle some time around 11am PST.

This is the second time I've flown with a stopover in Chicago ever, and the second time I've been stuck in a Chicago airport for an ungodly number of hours due to missing said connection. I think I should take it as a sign and not book flights that stop in Chicago anymore. I am very glad my return trip from Seattle is non-stop to London. Also, my phone doesn't work at all. I suspect that it is not actually quad band, so I'm probably going to have to track down another one somewhere.

Tentative plans in the US

Mon, 10 Dec 2007 18:16:41 GMT

So two weeks from now I'll be in Washington state, hanging out with my family. Here is my planned itinerary for where I'll be while I'm traveling to and in the US. Dates other than when I'm flying are approximate, and dates are in local time for whatever time zone I'm in at take off/landing. Confusing.

22 December: Stockholm to London flight
- 22 December - 23 December One night in London!
23 December: London to Seattle flight
- 23 December - ~27th December: Hanging out with family in Buckley
- ~27th December - ~2nd January: Seattle
- ~2nd January - ~4th January: Portland
- ~4th January - 6th January: Seattle
6 January: Seattle to SF flight
- 6 January - 9 January: Work/hang out in San Francisco
9 January: SF to Seattle flight
- 9 January - 14 January: More family/studying time in Buckley
14 January - 15th January: Seattle to London
- 15 January - 16 January: One more night in London!
16 January: London to Stockholm

And then on the 17th of January I get to try and take a final exam. Should be exciting!

I just got an unlocked quad-band mobile phone so I can use it pretty much anywhere in the world but South Korea and Japan. I will be using my Swedish phone number while I'm in Europe, and in the US I plan to switch to an American SIM card I bought on eBay which should soon arrive in the post. If you wish to be able to call/text me while I'm in the US please let me know and I will give you my number once I have it. Or if you want my Swedish number I can give you that too.

autocomplete=off on password fields sucks

Sun, 02 Dec 2007 21:21:53 GMT

The other day I decided to finally try and figure out why it is that Safari and other browsers do not offer to remember passwords for me on certain web sites. I regularly encounter this problem on some banking web sites, and the Yahoo login page for Flickr. Looks like the common way of keeping browsers from remembering passwords is the non-standard autocomplete HTML form attribute (assigned a value of "off"). This originally was a feature added to Microsoft Internet Explorer, but Firefox and Safari support it now, along with probably lots of other browsers.

The idea is presumably to keep users from storing passwords in an insecure manner on their computers. However, I use the built in keychain on Mac OS X, so it stores these remembered passwords in a fairly secure manner. Firefox's password manager also can encrypt stored passwords with a master passphrase if you tell it to. I don't memorize most of my passwords, so whenever I log in to a site that won't let me store a password in my keychain I have to go and decrypt a GnuPG encrypted text file I store all my passwords in. This essentially means I do the same thing as using the keychain would, but it requires doing pointless extra stupid work.

I should get to decide what my computer will do. I don't need web sites telling me how to secure things. This kind of behavior encourages users to choose crap passwords just so they can remember them, or re-use the same password for many sites/accounts. Both are, of course, bad for security.

Does anyone have any suggestions on how I can make Safari ignore the autocomplete form attribute? So far the only solutions I've seen for working around this involve patching WebCore, which seems scary and like total overkill. I don't want to use some other password manager either--I'd rather use the one built in to the OS. I tried using Privoxy with some filter rules, but gave up because it was taking too much effort and time to configure. I'm considering switching back to Firefox. I think it at has some extensions that will make it ignore this damn form attribute, or at least GreaseMonkey can do it for me. But it would be cool if I could just make Safari ignore this autocomplete attribute.

LaTeX math fonts and Leopard do not get along

Fri, 30 Nov 2007 19:05:02 GMT

Well, I've got a new problem now. My math fonts for LaTeX are all kinds of screwed up, as described here and many other places. Sometimes if I view a PDF with LaTeX generated equations in it in Preview everything looks fine, but if I just change focus away from Preview and go back it could get screwed up. Here's a video of what happens:

Googling told me I should try wiping out ATS databases with the following commands:


atsutil databases -removeUser
sudo atsutil databases -remove

(Gotta log out after running just the removeUser option, and reboot if you do the full on remove as root). This seems to provide temporary reprieve, but I start experiencing font breakage again after not too long of messing around with generating PDFs from LaTeX.

So annoying! I really hope this is just a display bug and my PDFs are actually fine when I email them to people or print them. It would be nice if this somehow gets fixed soon.

Some thoughts about Leopard

Fri, 30 Nov 2007 02:44:16 GMT

I bought the newest release of Mac OS X a little while back and installed it on my Macbook. I have mixed feelings about it.

First some things I like. Overall the way it looks is nice. A lot of people hate the new dock and transparent menubar, but they don't really bug me. I really like the rounded corners on contextual menus. All apps looking the same is awesome too. No more mix of brushed metal and pinstripes.

Spaces is awesome. I didn't really expect I'd like it as much as I did. I have not really used virtual desktops much in recent years of using X11 on unix systems, so I didn't think I'd be as stoked about Spaces as I am.

New iChat is cool. Lots of little things have been added that I was like "oh man I wanted this but didn't even really know it." Actually that can be said about a number of other applications too. iCal, Preview, Terminal, and others have a lot of these little changes that overall have a big improving effect.

The improvements to the Finder are also quite excellent. I haven't used Cover Flow much but it's cool. I really like Quick Look. The auto-discovery of network shares in the sidebar is handy, as are smart folders.

Now some things that make me both happy and disappointed. One of the biggest things I was looking forward to were improvements to Mail. Having RSS feeds in my mail reader makes me happy. Even better are how they sync up the read status with RSS feeds you have in Safari. Interestingly, I'd never used Safari for RSS feeds until now. I like that I can seamlessly switch between Mail and Safari for reading feeds now, depending on which one I'm in the mood to read with. I was a little bummed that my feeds all showed up as plain text in Mail, though, because I'd previously used defaults write com.apple.mail PreferPlainText -bool TRUE to force my email to always be plain text if possible (I do not like HTML email). I had to unset this in order to have HTML in my RSS feeds, which makes them look much nicer, but now I get HTML email too. It would be cool if we could get a separate PreferPlainTextMail and PreferPlainTextFeeds or something. It was also annoying how Safari and Mail can't import feeds from an OPML file.

Notes and to dos in Mail are cool, and I was relieved that you can change the default font away from being Marker Felt in the Mail preferences. I'm glad that to dos are shared between Mail and iCal, because sometimes I'd rather edit them in iCal yet still want them synched with my IMAP server by Mail. However, I was annoyed to discover just today that to dos I have synched with IMAP do not get synched to my iPod! You can apparently only sync to dos on local calendars with iPods. This is less annoying to me than it would be if I regularly used more than one Mac, but since I don't really need to use IMAP to synch to dos for now I just moved them all back to a local calendar, fixing iPod synching. I wish notes would sync to my iPod though, rather than me having to continue to manually drag files into its Notes folder.

Time Machine was another feature I was greatly looking forward to. I'm really glad to have backups I don't have to think about now. But, I was disappointed that you cannot choose to only have it back up, say, your home directory. I thought this would be possible. You can specifically exclude folders to back up, thankfully, but I really only care about backing up my own personal files. I try to keep everything I can in my home directory. Oh well, I have an external hard drive that is big enough that I can afford to back up pretty much the whole disk. I also wish Time Machine made block differential snapshots rather than file based, so you wouldn't need a fresh copy of a huge file every time just a few bits were changed, but I knew I wasn't going to get this.

The worst thing, though, is that Time Machine and FileVault don't play well together. Since this is a laptop, I have been using FileVault to keep my personal files encrypted in case someone jacks my computer. I'm somewhat paranoid. But if you use FileVault with Time Machine, it will back up your home directory as just the single encrypted sparse dmg that FileVault uses as its backing store. And it says it only backs it up when you're logged out. Presumably every time you change a file in your home directory, the whole huge dmg will get backed up anew. What I was hoping for was that I could have Time Machine back up only my home directory, and then do so only when I was logged in and the files were decrypted (that's the only time files are going to change in it anyway). This way I'd get nice incremental snapshot backups as usual, but could still keep the files all encrypted on my laptop's internal disk. Boo. For now I've just turned FileVault off because having easy backups with Time Machine is more important than my paranoia.

Now for things that totally suck. I did a fresh clean install, wiping my disk and just copying back my old home directory, because I wanted to clear off old crap. Despite this, I'm seeing more instability than I used to. Applications seem to crash more often, especially Mail.app. I also have been annoyed to find that with Python 2.4.4 installed from MacPorts I can't use pdb (Python debugger). Every time I just do pdb.set_trace(), python immediately crashes. This is likely not Apple's fault and the OS provided Python works fine, but I use MacPorts to easily install some other Python modules that Apple doesn't ship so it is annoying. Then, earlier tonight my Macbook just rebooted itself randomly. This might be a hardware problem (which of course sucks, but isn't Leopard's fault), but if its the OS that is real bad.

Then there's the new firewall. Many people have talked about how much it sucks. I agree. The idea of being able to allow incoming network access to only use specified applications isn't bad, but having that be the only control is lame. Having signed apps or those running as root be automatically trusted so the firewall opens up for them is also shitty. I think these kinds of things should be allowed for users to set their firewall policy with, but I want to be able to filter explicitly by port too. I want to be able to filter out traffic that is trying to connect to local services running as root. And I want to be able to do this without having to use ipfw from the command line. I could do these things in Tiger, so why remove the functionality? It would be better if Apple had let you switch to the old way of configuring the packet filter if desired, or at least given some more options for tweaking the new one. Even better than that is if they'd made a firewall that you could set up to notify you any time an application (regardless of its signature or uid) that hadn't been allowed to do so before tried to start listening on a local socket, and ask the user if he or she wanted to open a hole in the firewall for that app on that port. Outgoing filtering would be incredibly useful too. I'd love if the OS supported asking your permission any time an application wanted to connect to some remote socket you hadn't already explicitly allowed, like Little Snitch does.

I'm altogether not too impressed with security features in Leopard. Aside from the firewall, I guess they're better than Tiger, but I wish Apple had made bigger improvements. These posts and others about Leopard security features seem to show that Apple had some good ideas for security enhancements but didn't really take them too far. The application signing stuff is pretty lame since all it apparently does is warn you if an app that was signed and has been modified wants to get to your keychain or poke a hole in the ineffectual firewall. The sandbox business looks like it has a ton of potential, but I guess nothing actually uses it yet and it's totally undocumented. I'm not surprised that the security features aren't dazzling though. Software security is something that always bums me out when I think about it.

All this being said, overall I'm pretty happy with the upgrade. I hope some of the nastier problems I've encountered get ironed out soon in software updates.

Heather and I go to Helsinki and have Swedish Thanksgiving

Tue, 27 Nov 2007 01:20:01 GMT

For the last week and a half or so I had pacie visiting me here in Stockholm. She came all the way from Seattle. We had lots of fun. We went ice skating in Kungstragården, then met up with Heydar for bowling in Friedhemsplan and had food and drinks at Garlic and Shots, a place I'd been meaning to check out for months (and now can say I highly recommend).

Then we took a weekend trip to Helsinki. That was also pretty awesome. The Viking Line ferries are quite nice, even better than the boat that I took to Poland. It was a 16 hour trip each way but there was plenty of entertainment available on the ship, including some quite decent restaurants. We only spent a day in Helsinki itself, but had a good time just wandering around looking at various sites.

As usual, if you click on any of these photos you can see several more on Flickr. The following week we did more chilling in Stockholm. I had to do some not terribly exciting things like go to class, do homework, and work. Heather decided we should have Thanksgiving dinner though, and tracked down a number of Thanskgiving-ish foods. We had turkey, mashed potatoes, and apple pie, not to mention some delicious Bordeaux. Stuffing, cranberries, and pumpkin pie could not be located, but it was an excellent feast nonetheless.

Heather headed back home on Saturday and I've returned to my attempts at working and studying. Who wants to visit me next?!

P.S.I've got a few short video clips I've taken on my camera I've been kind of wanting to post somewhere. Anyone have recommendations for good video sharing sites to upload to? I want something like Flickr for video, but dunno if there's anything closer to that than Youtube.

Attention North America

Mon, 12 Nov 2007 21:49:09 GMT

I decided to come home for my winter break. I will be in Seattle, or at least somewhere in the US, from approximately December 23rd until January 14th. I found a sweet deal on a flight from London, so now I just have to secure plane tix between Stockholm and London, which should be possible for cheap thanks to Ryan Air.

Pretty math graphics

Tue, 06 Nov 2007 15:36:11 GMT

Even if you don't care about math, check out this pretty graph I made. I made the surface plot with Matlab, saved as an eps (encapsulated Postscript) file, then converted to a pdf with Preview.app on Mac OS X. In Matlab the figures never look this good, but when viewing it in Preview there's nice anti-aliasing and some awesome alpha transparency! Well, maybe it's only cool if you're a total nerd.

For those curious about what this is: I just did this homework assignment where I'm solving a simple parabolic partial differential equation in one spatial dimension, u_τ = u_ξξ. We used the Method of Lines to discretize the spatial dimension, turning the problem into a system of ordinary differential equations. We tried solving that system using some different ODE solvers, and this plot was made using the simple, inaccurate, and non-stiff Explicit Euler method. It turns out that if you don't make your time time steps smaller than about ½ (Δ ξ)^-2, where Δ ξ is the spatial step size, the solution is numerically unstable. This is why the u values are oscillating and blowing up to huge values near τ = 1 in this plot, making the actual solution impossible to see. If you're really curious, here is the assignment this is from.

Wow I'm amazed I could actually write that math just using HTML. Too bad everyone's browsers don't support some easy way of embedding LaTeX directly in HTML. Well, aside from jsMath, anyway, which I don't think I can use on LiveJournal since I'd have to embed JavaScript in my post.

Poland trip

Sat, 03 Nov 2007 15:14:51 GMT

Earlier this week I took a quick trip to Gdynia and Gdańsk, Poland, via ferry from Karlskrona, Sweden. This trip was organized by ESN Sweden, so there were a few hundred other international/exchange students attending universities in Sweden that I went along with.

The start and end of the trip were rather long, boring bus rides across Sweden (Karlskrona is far in the south). I learned that the Swedish countryside is really quite rural, which makes sense given that there are only nine million people in this country. The more fun part of the journey itself was the ferry. We took a Stena Line ferry, which is this massive ship that looked to me more like a cruise ship than the kind of ferries there are in America, but it took cars on board too. The passage was about twelve hours long, overnight, so we had cabins on the boat and there was plenty of eating, drinking, and gambling available to pass the time. I did not find the food impressive. The booze was cheaper than in Sweden though (but not as cheap as actually in Poland), so that was pretty awesome.

We arrived in Gdynia early in the morning. As Poland hasn't implemented Schengen yet, we got to wait for a long time in a queue for passport control. At least I got some more stamps in my passport. After completing the border crossing we took a bus to Gdańsk and were given a tour from some ESN people from Poland. It was great to learn a little about Polish history, because I knew almost nothing besides it had been invaded by the Germans early in WWII and then got to live under the unpleasant rule of the Soviets until the recent past.

After the sightseeing and lunch, we took buses back to Gdynia for a little shopping before boarding the ferry for the return trip. Poland is a cheap place to shop. I didn't buy much though, as I didn't really have an easy way to carry a lot of stuff, nor do I have a lot of excess cash I felt the need to blow.

The return ferry trip was similar to the journey over, but it seemed like people were partying even harder on the way back. Many people had bought large quantities of cheap Polish booze (like suitcases full, or hand trucks with stacked up cases of beer), so there was a lot of drinking all over the boat. We'd been told that we're not allowed to drink outside of the bars, and then only drinks bought in the bar, but there were hundreds of students scattered about everywhere drinking the cases of beer, boxes of wine, and bottles of vodka they'd bought anyway. I think I was the only one in my cabin who got some real sleep that night. I was woken up at 6 or 7 in the morning to one of the guys who I'd shared it with packing up since we were about to dock, and he was still incredibly drunk. It must have sucked for a lot of people to have to go sit on a bus for hours after that, but then the other students on the trip were probably mostly all younger than me so can probably still take that sort of abuse.

There were a few couple of rather surprising things about the trip. First of all, there were a ton of Americans. Way more than I'd seen any other time in Sweden. A lot of them seemed to be exchange students at Linköping University. Somehow they have attracted a lot more Americans there than KTH has I guess. The majority of the students on the trip were from Europe though, especially Spain, with a few more from various other places in the world. The other surprise was that Poland seems to be a less impoverished place than I'd feared it might be. Sure it's not as wealthy as most Western European countries, but they seem to have a rapidly growing economy. I saw a lot of new construction and clearing away of the depressing remnants of the Soviet era. The ugly old gray apartment buildings remaining appeared mostly abandoned, with a lot of new looking more cheerful buildings to replace them.

The trip was rather short but quite good, and I would be happy to go back some time.

Stureplan Kind of Sucks

Sat, 27 Oct 2007 18:26:35 GMT

The first period (semesters are split into two periods here, with some courses only lasting for a single period) just ended and I finished up exams, so last night I went out with Heydar to find some fun. We started at his place, making some shish kebabs and rice for dinner. Yum. Then we were talking with other folks in his corridor about going to some place in Medborgarplatsen, but we balked when we learned it'd be 100kr. just for the cover. Everywhere had a cover last night I guess, because it was just payday for nearly everyone in Stockholm. So instead we went to the Lappis pub, a little student pub in his neighborhood that was having a sort of Halloween party, to meet up with Negar.

The pub was not terribly exciting, and everyone seemed to be trying to find somewhere else to go. Heydar and I walked around a little bit, and on the way back in to the pub this girl yelled to us that we shouldn't go in there because it was terribly boring. We started talking to her, and she seemed to have a plan to go some place in the city that was fun. We both are into adventures with new people, so this sounded fun. Negar wanted to stay at the pub to wait for a friend, so Heydar and I followed this girl, Emily, and her friend Heidi. We ended up going to Stureplan, a neighborhood in Stockholm that the rich, famous, and yuppies flock to for drinking on the weekends. Heidi was not stoked about the clubs here, but Emily really wanted to go and Heydar and I were just following along.

We went to several different places and turned back either because the cover was too high or the doormen didn't know us/didn't think we looked rich enough to be let in. I've never before bothered trying to go to places where the people working the door get to decide who comes in. It's stupid. We ended up at a place called Esque, eventually, where one of the doormen did know Emily. It too was too expensive at 150kr. (~$24) with a coat check fee of 30kr. (~$5), but we said to hell with it and went in anyway. The place was packed with attractive people who looked like they had money. The boys were mostly taller and prettier than me, and so were the girls. I liked some of the decor of the place, like the color changing lighting for the downstairs dance floor:

The music was occasionally decent so we danced a little. A lot of it was pretty lame though. We had some unsurprisingly overpriced beer, and I was dumb enough to buy an outrageously expensive mixed drink.

One of the girls we came with, Emily, started making out with some guy not long after we got there, and disappeared. Heydar, Heidi, and I hung out, failing to communicate easily with each other over the music. We took some photos of each other though.

We stuck around for a little while, but it was getting quite late. Heidi seemed to be bored and took off, then Heydar and I did the same shortly after. All in all it was a really expensive evening that was fairly unsatisfying. At least it was weird sometimes, keeping the situation interesting. It seemed like people were just there to spend too much money getting drunk and trying to find someone to take home, which I think is pretty typical of clubs in Sweden (and probably most everywhere in the world). I don't think I need to bother to do that again, though I'm glad I tried one of these places once. I think I'll stick with parties and pubs where I can more easily chat with friends and new people, unless I find some place with good enough music that there's some other attraction besides the meat market.

Next on the agenda: tomorrow I'm off to Poland! Be back on Tuesday with some pictures and news.