Recently I got a brand spankin new MacBook Pro (MBP) to replace my three-year-old one. One of the things I did not want to deal with is setting up a new computer from scratch and reconfiguring and reinstalling everything I already had on my old MBP. I have things pretty-well organized, I know where things are, and I remember when I rebuilt from scratch from Tiger to Leopard I lost a bunch of settings and such because I hadn't used any kind of migration software. Not this time. This time I wanted my new computer to essentially be my old computer, but with more memory and faster with no hassles.

There are a few options I considered. First, simply take a SuperDuper backup and restore directly to the new MBP. I researched this a lot, talked to people who've done this both successfully and unsuccessfully, and talked to a Genius at the Apple store. The second option was to use the Migration Assistant to transfer from old to new. After all the research, I decided against restoring from SuperDuper for several reasons. First, it seemed to be hit or miss: some people reported success and some did not. Second, and more importantly, I was transferring from a circa August 2006 MBP, in fact one of the first revs that had the Intel chips inside, to a circa June 2009 MBP with the new trackpad and all the other updated jazz. I was mostly concerned that there could have been enough difference between the old and new computers' hardware and software drivers and that a direct restore would not contain up-to-date drivers and whatever else that could screw things up. So I chose to explore using Migration Assistant, which promised a very easy transfer of all files and settings.

So then I ran into the first snag, which is that Migration Assistant does not transfer File Vault-ed user accounts, and I happen to use FileVault. Doh. So I thought, "OK no problem I'll simply turn off FileVault on the old machine first." Except that I only had about 7GB of space left on my hard drive, and turning FileVault off needs about as much free space as your home directory currently takes up. So if my home directory is currently 50GB, then I need about 50GB free. Double Doh, because I didn't have that kind of space! To solve all these problems, here is what I did, for anyone else who might be trying to do the same thing:

Step 1 - Backup Original Mac

Make a SuperDuper backup of the old MBP onto a portable external hard drive. (I actually made two copies on two different external hard drives, just in case something got screwed up later.) The external drive should contain plenty of space, enough so you can turn off FileVault on your home directory.

Step 2 - Turn off FileVault on External Drive

Restart the old Mac and boot from the SuperDuper backup. (You hold down the option key during startup to get the screen where you can choose to boot from the Mac hard drive or the SuperDuper backup on the external drive.) Note at this point you are now running Mac OS X on the external hard drive. Log into the FileVault-ed account, go to System Preferences, and turn FileVault off. (This is why you needed to make sure the external drive has enough space to turn off FileVault, since you are turing it off there, not on your Mac's hard drive!) Now go grab something to eat and/or watch a movie as this step can take a few hours depending on how much data you have.

Once complete, log out and shut down the external drive. You are now ready to transfer.

Step 3 - Prepare for Migration Assistant on New Mac

Log into your new Mac, and connect the external drive that contains the freshly un-FileVault-ed SuperDuper bootable backup of the original Mac. If you or someone else already setup a new user account on the new Mac that has the same username as your old account does, then create a new account with Administrator privileges (e.g. "MigrationAccount") and then delete the account that you will be transferring to. For example, if your old Mac account username was "bsmith" and the new Mac has an account with the same username, remove the "bsmith" account on the new Mac. Otherwise when you attempt the migration you might receive the following message like I did the first time I tried: "There is an existing user account with the same name as an account you are transferring." This wouldn't have been an issue, except that the option to replace the account was disabled and so Migration Assistant was refusing to overwrite it. Thus you should delete it first.

Step 4 - Run Migration Assistant

On the new Mac, run Migration Assistant and answer the questions. You'll be transferring from the external SuperDuper backup to the new Mac. The questions are easy and straightforward. Go grab something to drink or watch some TV, as it'll take a while to transfer all your old files and settings from the external drive to the new Mac. I'll just assume everything went well, because it did for me. If something went wrong, well, I don't have answers other than maybe to try, try, try again from scratch.

Step 5 - Turn FileVault Back On

On the new Mac, turn FileVault on for the newly migrated account, e.g. if the "bsmith" account previously had FileVault on, then login as "bsmith" and turn on FileVault in System Preferences. Tick tock. More waiting as Mac OS X encrypts all the data in your home directory. Once this process completes, your new Mac should be pretty much the same as your old Mac, with all the same files and settings like Desktop, Screen Saver, etc. and with all your applications transferred successfully. And you are back up running with FileVault enabled.

Step 6 - Secure Erase External Hard Drive

At this point you have the new Mac setup with FileVault, and the old Mac still has FileVault on as well since you migrated from the external drive. But, the external drive now has unencrypted data sitting around since you turned FileVault off on it. Open up Disk Utility and do a secure erase of the un-FieVaulted external drive. Depending on which option you choose, e.g. "Zero Out Data", "7-Pass Erase", "35-Pass Erase", etc., the erase process can take a long time, as in days. In other words, a 7- pass write overwrites every part of the disk 7 times to sanitize it and make recovery of the unencrypted information much harder, and takes 7 times longer than just zeroing out the data, which writes zeroes all over data on the disk.

I only did a zero out of the data, because I knew I was going to immediately overwrite that external drive with a new SuperDuper backup once I was done. If you need more insurance than that, a 7-pass erase confirms to the DoD 5220.22-M specification which is probably good enough. (Actually I started out using 7-pass erase until I saw it was going to take a day or two, and then I got a tad lazy and just did the zero out. Perhaps that is bad, but I didn't feel like waiting that long, and it's not like I have data for 100,000 employees on my hard drive in an Excel spreadsheet anyway. Just a lot of code and presentations and such, really.)

Step 7 - Backup New Mac

Make a fresh SuperDuper backup of the new Mac.

Coda

Although all the above sounds like it took a long time, the waiting and time was mostly due to having to turn FileVault off and then on and doing the secure erase. Migration Assistant itself takes a fair amount of time but is totally worth it. Overall the entire process from start to finish on my old MBP with a 100GB hard drive containing only 7GB free space took between five and six hours, which is way less time than if I had tried to start over from scratch with the new Mac. I do wonder why Apple cannot just allow Migration Assistant to transfer accounts with FileVault enabled, because then pretty much all you'd need to do is run Migration Assistant directly, and you wouldn't need to go through all the drama.

If you want/need to run VisualVM on a 32-bit Macbook Pro you'll need to do a couple of things. First, download and install Soy Latte, using these instructions - this gets you a Java 6 JDK/JRE on your 32-bit Macbook Pro. Second, download VisualVM and extract it wherever, e.g. /usr/local/visualvm. If you now try to run VisualVM you'll get the following error message:

$ ./visualvm
./..//platform9/lib/nbexec: line 489: /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home/bin/java: Bad CPU type in executable

Oops. After looking at the bin/visualvm script I noticed it is looking for an environment variable named "jdkhome." So the third step is to export an environment variable named 'jdkhome' that points to wherever you installed Soy Latte:

export jdkhome=/usr/local/soylatte16-i386-1.0.3

Now run the bin/visualvm script from the command line. Oh, almost forgot to mention that you should also have X11 installed, which it will be by default on Mac OS X Leopard. Now if all went well, you should have VisualVM up and running!

So, after having actually written a blog entry covering each day of the iPhone bootcamp at Big Nerd Ranch, I thought a more broad summary would be in order. (That, and I'm sitting in the airport waiting for my flight this evening.) Anyway, the iPhone bootcamp was my second BNR class (I took the Cocoa bootcamp last April and wrote a summary blog about it here.)

As with the Cocoa bootcamp, I had a great time and learned a ton about iPhone development. I met a lot of really cool and interesting people with a wide range of backgrounds and experiences. This seems to be a trend at BNR, that the people who attend are people who have a variety of knowledge and experience, and bring totally different perspectives to the class. The students who attend are also highly motivated people in general, which, when combined with excellent instruction and great lab coding exercises all week, makes for a great learning environment.

Another interesting thing that happens at BNR is that in this environment, you somehow don't burn out and can basically write code all day every day and many people keep at it into the night hours. I think this is due to the way the BNR classes combine short, targeted lecture with lots and lots and lots of hands-on coding. In addition, taking an afternoon hike through untouched nature really helps to refresh you and keep energy levels up. (Maybe if more companies, and the USA for that matter, encouraged this kind of thing people would actually be more productive rather than less.) And because of the diversity of the students, every meal combines good food with interesting conversation.

So, thanks to our instructors Joe and Brian for a great week of learning and to all the students for making it a great experience. Can't wait to take the OpenGL bootcamp sometime in the future.

Today is Day 5 — the final day — of the iPhone bootcamp at Big Nerd Ranch, taught by Joe Conway. The last day of Big Nerd Ranch bootcamps are half-days so you have breakfast, have class until lunch, have lunch, and then shuttle back to the airport. Unfortunately for me my flight isn't until 7pm so I have a lot of time to write this entry!

See here for a list of each day's blog entries.

Preferences

First up on this last day of iPhone bootcamp is preferences, which allow an app to keep user settings in a centralized location. While you can store user settings yourself using a custom UI, the easiest way is to use the iPhone's built-in Settings app. The Settings app is the central location where apps can store user settings. It is also where all the other common iPhone settings are, which is convenient.

You work with the NSUserDefaults object to store app settings based on the app's bundle ID, for example com.acme.MyKillerApp. You'll also want to ensure you provide "factory default" settings using the registerDefaults method; these settings will be used if the user has not changed anything. NSUserDefaults is basically a dictionary of key-value pairs, and you obtain the standard user defaults using the standardUserDefaults method. From that point you can write user settings using methods like setObject:forKey, setInteger:forKey, and so on, and you can remove settings using removeObjectForKey. Similarly, you read settings using methods like objectForKey, integerForKey, and so forth.

As mentioned earlier, the Settings app is a uniform way of setting preferences for all apps. Users know where to look for setting preferences for apps there. In addition, managing the settings separately from your application also saves screen real estate, which is important since the screen isn't all that big. You define the settings for your application using the Settings Bundle. This is a standard Property List. You use special property keys, such as PSToggleSwitchSpecifier, to define the settings for your application. The Settings app uses the Settings bundle and property list to create the settings UI for your app. For example, if you define settings for a PSToggleSwitchSpecifier, a PSTextFieldSpecifier, and a PSMultiValueSpecifier, the user will see a toggle switch, a text field, and a slider when she goes to edit your app's settings.

For the lab exercise, we modified our Random Number app (from Day 4 during the Web Services section) to have user settings for how the random numbers are generated — for example minimum number and the range of numbers. It is quite easy to add user settings to your app in the iPhone using the Settings app and bundle.

Instruments

Joe briefly talked about using the Instruments app to do powerful debugging, for example to detect memory leaks in your app. He then demonstrated using the Leaks tool within Instruments to track a memory leak — which he had previously introduced intentionally — in the Tile Game app. Leaks was able to pinpoint the exact line of code where a leaked object (i.e. it was not released) was allocated. This is pretty cool.

Joe also showed what leaks look like when they come from C code versus Objective-C code. C-code allocation leaks (i.e. allocated using malloc) show up in Instruments as just 'General Block' and from what I gather are probably not that fun to track down the exact cause. Leaks in Objective-C code are easier, and as I just mentioned, Leaks can show you the exact line of code where a leaked object was allocated.

Networking

By this time, it is getting closer to lunch, and the end of the class. Sad, I know. Anyway, probably one of the hardest and broadest topics was saved for last, given that you could spend an entire course on nothing but network programming. Anyway, on the iPhone a key concept when doing network programming is "reachability." Reachability does not mean that a network resource is definitely available; rather it means the resource is "not impossible" to reach. Another important thing on the iPhone is figuring out what type of connection you have, for example EDGE or 3G or Wi-Fi. You might choose to do different things based on the type of connection.

With the SystemConfiguration framework you can determine if the outside world is reachable, again with the caveat the "reachable" means "not impossible to reach." When coding you work with "reachability references" and "reachability flags" which describe the type of connection, for example reachable, connection required, is wide-area network, and so on.

We then learned a bit about Bonjour, which is basically a zero-configuration network service discovery mechanism that works on all platforms, has implementations in many languages, and is easy to use. For example, Bonjour makes it ridiculously easy to find printers on a network, as opposed to the way you have to do it in other operating systems. You can use Bonjour on the iPhone to discover and resolve Bonjour services. You use NSNetServices and NSNetServiceBrowser to accomplish this, and you specify a delegate to receive notifications when services appear and disappear.

In addition to Bonjour, you can also send and receive data over the network as you would expect. To send and receive data you can either use a C-based Core Foundation interface or use a stream-based interface with CFStream. You register read and write callbacks with the main iPhone run loop, which calls your functions when network events occur.

Network programming is really hard, since there are so many things that can go wrong and you need to deal with many if not all of them. Joe recommended that before jumping right into hardcore networking, developers should become familiar with the concepts and recommended the Beej's guide to network programming as a good primer. Given that I've really only done simple socket programming in higher-level APIs like Java's, and have not really done much of it, I'll need to check that out. And so this concludes this episode of iPhone bootcamp blog, since it is now time for lunch and, sadly, the course is over!

Random Thoughts

This week has been a really intensive introduction to iPhone programming. We've gone from a very simple app on Day 1 and covered all kinds of things like form-based UIs and text manipulation; Core Location; Core Graphics; view transitions and Core Animation; using the iPhone camera and accelerometer; retrieving web-based data; manipulating Address Book data; setting user preferences, and finally networking and debugging using Instruments. We've basically covered an entire book's worth of content and written about 10 iPhone applications ranging from simple to not-so-simple. If you are interested in programming the iPhone, I definitely recommend checking out the iPhone bootcamp at Big Nerd Ranch. Because the OpenGL stuff we did on the iPhone was so cool, I'm thinking my next course to take might be the OpenGL bootcamp but that probably won't happen until next year sometime! With my new knowledge I plan to go home and try my hand at creating a snowflake or snowstorm application that my daughters can play with. If I actually get it working maybe I'll write something about it.