Mountain Lion

Get the software

Just open the App Store application, search for Mount Lion (it may be on the front page as popular download), and buy it. The download is about 4 GB, so you will want to start with this step. Or buy it on CD somewhere.

Cleanup

I do not think you need much extra hard disk space for the new Mac OS X version, but this is still a good time to make some extra room. Disk Inventory can be a good assistent here, showing you which files or directories take up the most space.

Your Downloads directory may also contain old installers that can be deleted. Maybe you have some backups from 2004 that you finally realize you will not need anymore.

Be sure to go to the Trash folder and empty it.

Backup

Make sure you have a backup, probably with the Time Machine. If you are a developer, make sure all your source code changes have been committed and pushed.

Upgrade

Close your programs and run the Mountain Lion installer. I think this took about half an hour.

TRIM Enabler

If you have a Solid State Disk, you are probably using TRIM Enabler. After the first reboot, you will need to start that application and enable it again. Then you probably need to restart again, but the application will tell you this.

XCode

If you are a developer, you will want to install the latest XCode from Apple. Open the App Store and download it. It is about 1.6 GB so this will again take a while.

When you install it, make sure to install the command line tools too. Open XCode, open the Preferences, go to the Downloads section and download and install the command line tools.

Status

At this point, as I am a Plone developer, I tried starting an existing zope instance. This worked fine. But then I tried rebuilding the Python buildout, specifically installing the 3.3 one, which failed. If I recall correctly, no good C compiler could be found. I have that in Mac ports, so I needed to update those.

Mac ports

You will need to completely reinstall the Mac ports package and your active ports. Follow instructions at https://trac.macports.org/wiki/Migration

For step 1 under 'Reinstall ports' you may want to gather only the active ports:

port -qv installed | grep active > myports.txt

Then you can open that file and remove the lines for ports that you think are not needed anymore. Maybe keep a copy of the original file in case you later find things are missing.

In step 3 you execute this:

sudo port clean all

This might fail with an error like this:

Error: Unable to open port: can't read "build.pre_args": can't read
"build.cmd": Failed to locate 'gnumake' in path:
'/opt/local/bin:/opt/local/sbin:/bin:/sbin:/usr/bin:/usr/sbin' or at
its MacPorts configuration time location, did you move it?

If that is the case, then most likely you have not installed the command line tools of XCode. See http://guide.macports.org/chunked/installing.xcode.html on how to do this. Or see above.

Note that freshly installing all you favorite mac ports will take a while. You may want to grab a drink or some sleep at this point.

Python buildout

If you are developing Plone, you may already be using the Python buildout. This is on github now. It seems best to rebuild your pythons at this point. Use the bootstrap-1.4.4.py file, otherwise you will run into problems.

Initial impressions

Wow, it feels fast! My feeling is that starting an application is now twice as fast. Maybe I would have had the same result with a fresh install of Snow Leopard, but it sure is nice. Note that I was already using a Solid State Disk, so it was already fast.

I have switched the natural scrolling off (System Preferences, Hardware, Mouse). Maybe I should just try it, but I am used to the old behaviour.

For a while, iTunes started up and began playing music without me doing anything. It did this lots of times. Today I did not see this anymore.

Mail looks rather differently. I started it up and did not see my mail accounts and folders, just some messages. So I quit Mail and started ThunderBird, which is still my favorite mail reader because I know its keyboard short cuts. The Mail interface can be easily tweaked though, nothing wrong with it, just a bit surprising for me the first time. I think the layout will work fine, at least on wide screens.