I’m in the process of setting up my very first production server using Ubuntu, and I’ve ended up spending a lot of time reading about security online.  Since I’ve always let the ops team worry about setting up environments, etc., I’ve now learned that there are a lot of different concerns to think about.

One decision in particular is bugging me right now – how to secure the root account on my new machine?  So far, I’ve been doing a lot of the work by SSHing into the root account.  On the whole, this doesn’t seem so great, since it can be dangerous to use root day-to-day and always have the ability to delete anything on the system.

Ubuntu recommends that I create another user with sudo permission and use that day-to-day.  However, since Ubuntu also asks users for their own password when using sudo (rather than the root password), I feel this isn’t intrinsically any more secure than just having a root account.  In either case, a cracker would only have to find one password to take over the system.

So, my thought is to create a second user with sudo permission, change sudo to require the use of the root password, and disable remote logins for root.

Advantages:

• To gain access to root, a hacker would have to find the second username, that username’s password, and the root password.
• Sudo provides logging of all executed commands.
• Using the sudoers file, I could potentially mark some commands as offline to even the secondary user.  This could be useful to make sure the user can’t change the root password or access certain directories.

Disadvantages:

• Since I don’t have local access to my machine, I’m worried about turning off SSH access to root.  What if something happens to the secondary user?  Would I be locked out?  I’m using Linode as my host, so I think I might actually be able to use their online Lish terminal to log in as root as if it were local access.
• Every admin user would need to know the root password in order to use sudo.  I think this is ok because I’ll really only have one admin user, and that will be me.

In all, I think that the advantages of my plan outweigh the disadvantages.  What do you think?

Those of you who run a lot and those of us that want to go running a lot but don’t have inspiration may be interested in my sister Erin’s new blog. She’s writing up a lot of Boston running tours with historical information about the places you will run by. She’s also doing the same thing for San Francisco, where she lives now.

Eventually, I believe the idea is to turn them into podcasts that you can listen to as you run at 7-8 minutes per mile.

Anyway, I’m excited for her and thought I’d help her spread the news. Feel free to tell any of your friends in Boston or San Francisco to check out cityruntours.com.

Here’s my comment for my latest SVN commit:

How can I forget?
Don’t access variables,
Unless they’re not null.
Bug-ID GD-34785

I’ve decided to give iPhone development a try.  I have a few ideas for cool mobile apps that I’d love to implement so that I can learn a new platform, a new language, and maybe make some money on the side…  However, I’ve remembered what I dislike most about programming – configuration.

I started out trying interface builder and got a basic interface to show up pretty quickly, but it was rather confusing and I didn’t really know what was going on.  Next, I thought I should probably just go through the tutorials in my book (iPhone SDK Application Development by O’Reilly) so that I could get an overview of what’s actually possible with the iPhone.  That way, when I restart building my own apps it will be much faster because I’ll know what I’m doing.

However, I’ve now been trying to get the TextView example in Chapter 3 (Hello World) to work for almost a week!  I typed in all the code correctly (twice, into two separate projects), and it compiles fine, but all I get on the iPhone simulator is a black screen!  After a while, I found the debugger console button in XCode and realized I was getting the following errors:

warning: Unable to read symbols for “/System/Library/Frameworks/UIKit.framework/UIKit” (file not found).
warning: Unable to read symbols from “UIKit” (not yet mapped into memory).
warning: Unable to read symbols for “/System/Library/Frameworks/CoreGraphics.framework/CoreGraphics” (file not found).
warning: Unable to read symbols from “CoreGraphics” (not yet mapped into memory).

These frameworks are quite obviously linked in XCode (because the code completion works and the project compiles fine), but for some reason they don’t show up in the simulator.  After searching online, I’ve gotten to the point where I think it has to do with the way they’re referenced in XCode and that when running on the simulator, the application doesn’t actually compile all the references together; it just starts running without them, so you have to run it from within XCode.   Some people have also said that it had to do with breakpoints in code.  However, I’m running from within XCode and I don’t have any breakpoints, so I think it must be a file location configuration issue.  Now, I’ve had no luck finding any solutions online or by experimenting…

I’ll let you know how it works out; I’m not going to give up on this.

—- Update – March 1, 2009 —-

Well, the Hello World example started working… First thing to note is that the “file not found” type warnings I noted above don’t actually seem to be related to the problem; now that it works, they still show up.

I fixed the blank black screen by cleaning all targets (in the Build menu), then rewriting Hello World to directly use a TextView instead of manually subclassing UIView myself. Also, I didn’t allocate a window object; I just started using it and let the synthesize keyword work for me (before, I was trying to remove Interface Builder from the project, like it recommended in the book. Here’s the code that first worked (I called the project “Arg” because I was so frustrated):

ArgAppDelegate.h:

#import

@end


ArgAppDelegate.m:

#import
#import
#import
#import "ArgAppDelegate.h"

- (void)dealloc {
[window release];
[super dealloc];
}
@end


This compiled fine and the text view showed up correctly, etc. Next, I slowly changed the code one line at a time back to the original code, compiling at each step, to see if I could find the line that was causing the problem. Unfortunately, I eventually came back to the original code and it worked…

ArgAppDelegate.h:

#import

@end


ArgAppDelegate.m:


#import
#import
#import
#import "ArgAppDelegate.h"

- (void)dealloc {
[myMainView release];
[window release];
[super dealloc];
}


main.m:


#import

NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, @"ArgAppDelegate");
[pool release];
return retVal;
}


I hope this helps somewhat to anyone having the same problem. I found this incredibly frustrating and am not entirely happy about my solution here. I still don’t really know why it happened in the first place, so I’m worried it will come up again in the future. Let’s hope not!

As you know, over the last two years, I’ve learned a bit of Chinese.  I’ve taken classes, but a lot of what I’ve learned has come through self-study outside of class as well.  Here’s a list of resources that should help you along:

1.  ChinesePod – This site hosts a daily podcast with a 20-minute or so Chinese lesson.  They also have lots of resources for studying characters, etc.  I don’t actually spend a lot of time on the site, but I subscribed to the podcast and listen to them on the way to work in the morning; they’re not only good practice, but fun as well.  The whole cast sounds like they’re having fun at work, which makes the lessons quite inviting.  Unfortunately, this month, they changed the format so that the free iTunes feed only contains newbie lessons (they have Newbie, Beginner, Intermediate, Advanced-Intermediate, and Advanced).  I will probably start paying for the advanced content, because it is such a good way to practice.

2.  Pimsleur Language CDs – I’ve actually done Pimsleur for two languages now (German for 8 CDs and Chinese for 90) and can’t recommend it highly enough.  The Pimsleur method is entirely audio-based, so you won’t learn how to read, but you will learn how to speak and understand some simple sentences very quickly.  These are a bit more interactive than ChinesePod and work best when you actually respond outloud, so you probably shouldn’t do them on the subway.  Also, they are timed so that you optimally do one half-hour lesson a day and the next day get reminded about the material from the day before; this helps it move to your long-term memory.  I set up my computer to play one lesson a day as my alarm clock and did them in the morning before getting out of bed.  Altogether, there are three months of lessons available.

3.  Set up your computer to allow you to type in Chinese.  This is extremely simple on a Mac, since Chinese support is installed by default, but on a PC you’ll have to install the East-Asia Language Pack, which is a little bit of a hassle (you need the CD).  Before you do this, however, you should make sure you really know pinyin and can write the pinyin for a word after hearing it.  Typing in Chinese is a bit different than you may be used to – if you use the pinyin input method, you type a few syllables at a time, press space, then are presented with options for each of the characters.  Since so many characters in Chinese use the same pinyin (especially when it’s toneless), you have to be able to decide which is the right character, which can help with character recognition skills as well.

4.  Install Firefox and use the Chinese Pera-kun extension.  I used to recommend WordChamp, but this extension is like that except that it works so much more smoothly.  With this extension turned on, when you go to a page with Chinese text, all you have to do is hold your mouse over the characters that you don’t know.  A small popup will appear with the pronunciation and the definition, and it will try to find whole multi-character words in the text as well.  This is great, because as you learn to read more, you use it less.  Plus, it provides a one-to-one mapping between Chinese characters and meaning.  Translation tools like Google Translate will usually translate the whole page at a time, losing the information about the characters, how they sound, which character relates to which English meaning, etc.

5.  Online Chinese-English dictionaries.  There are a lot of them; I usually use www.mandarintools.com, but that’s just because it’s easy to remember; the design is actually not that good (you can’t directly link to the dictionary, for example).

6.  Finally, don’t forget that you have to use a language to really learn it.  Make friends with Chinese people and surprise them with some Mandarin phrases.  It can be a bit nerve-racking at first, but once you’ve reached the level where they can understand you, it will help a lot.  It will also make you realize how little you really know and give you inspiration to learn more.

Of course, all these tips aside, classes really help a lot.  A good price for Chinese classes is about $35/hour.  Even $50/hour is ok if you have an engaging native-speaker for a teacher (who also knows enough English to answer questions easily) and a good class.

Hope this helps.  Have fun studying Chinese; I know I do!

好好学习天天向上！

今天我要再用中文写日记。

昨天我工作一年了。  很长吗？我听说这是很段的时间工作。  但是这也是我最长的时间只作一个计划。  在大学我的计划都是三个月的。  虽然这是很长的我有时候觉得我不太孳。  我觉得这个感情是因为工作总是有别的问题。  我做完一个问题就开始别的。  很有意思的感情。  我想一个“feeling of completion”。

hmm有别的吗？  有。  今天晚上我看了我的姐姐的履历表。  我体认了我喜欢读履历表。  上大学的时候我做这么多面试所以我也想一想我的履历表。  用LaTeX写。  我觉得我现在知道很多履历表的东西。  要是你想我帮你，当然可以。

今天我也看了我的同事的blog。Lis是一个公司的作家所以她的日记很好。  名字是A Millenial Speaks。  我建议这个。

明天我要写很多中文的电脑工具。  我现在用了很多。

再见！

我从中国回来波士顿了。  先我觉得我得生化比较不一样。  每个东西很不一样－我有新的石室友，有的朋友们搬家走了，有的朋友们搬家到了，我知道我非常喜欢中国了。  现在我觉得我点点忘了这个感情。  每天我工作吃饭睡觉。 忙点。  我非常不要忘我的感情。  有一天我一定要住在一个外国可是现在我也觉得住在波士顿在VistaPrint工作对我生活比较好。  有的人可以说我太responsible了（怎么说？我的字典不能帮我。）我希望有好的生活所以现在我需要工作储蓄。感叹。

有一天

Map of my trip in Korea and China

Best Places to get pictures taken:

1. Tiananmen Square (Beijing)
2. The Bund (Shanghai)

Tastiest food:

• Hongdong Garden (Gimhae, South Korea)

• Huangting in the Peninsula Hotel (Beijing)

Most surprising food:

• Duck Heads (Shanghai – I thought we were ordering shrimp)

Best meal for the buck:

• Jianbing (Beijing and Shanghai – almost a breakfast burrito for 30 cents)

Best Restaurant slogan:

Check out the logo - Mr. Pizza is a player

• Mr. Pizza – Love for Women (South Korea) Also winner of the best pizza ingredient: crust stuffed with mashed sweet potatoes.

Sketchiest transportation:

• Halfway between a vespa and a motorbike.  With three people.  And all our luggage.  But it was only 5 kuai! (70 cents?)

Most appropriate exit from a museum:

• Leaving the Urban Planning exhibit in Shanghai into a giant underground mall from which it took over 45 minutes to find an exit.

Most surprising meal (for someone else):

• Taking a girl I had just met ten minutes before to a 5-star restaurant (Huangting) because I had budgeted too much money and had decided to take the first person I met to the most expensive restaurant I could find.

Best hotel feature:

• Renting a cell phone for $1.50/day.  Wow, what a great idea.

Best Club:

• Coco Banana (best fellow dancers, too)

Most awesome and intimidating Chef:

• KungFu Pasta Chef making longevity noodles on my birthday.

Best Athlete:

• Michael Phelps

Best conversation:

• 35 minutes of talking to a taxi driver in Beijing who guessed that I’d lived in China for two or three years.  That was the moment when I really got Chinese.

Most frustrating 20 minutes:

• Getting stopped on the great wall by men from the army and not having a ticket because my tour guide was trying to scam us and having to speak for the two guys from the Netherlands as well because I spoke Chinese.  We eventually just paid them again, and then I had to convince the tour guide to give us our money back at the end.  Haha.

Best choice for what to pack:

• A week’s supply of Immodium AD

Place most likely to return:

• Beijing

Hmm, I guess that’s enough for now.  If you want, I’ll put more up later when I think of them!

Well, the whole “blog my trip thing” didn’t work this time…  Internet access was spotty in China to say the least.  I did write a journal, though (I’m almost done!), but I haven’t decided if I’ll publish it or save it for me.  Perhaps I’ll put up a few stories.

Sorry for the unanswered expectations, guys!

This claims to be a collection of the world’s ten oldest jokes

The World’s Oldest Jokes

I doubt it really is (especially since the last one comes from a whole book of jokes), but it’s fascinating to see what people find funny over time.