As someone responsible for supporting Macs, I carry around an external drive (LaCie Rugged with USB2, FW400, and FW800 connectors) that holds all my tools, as well as different versions of OS X, reaching from 10.3 (PowerPC) to 10.5. Recently, I had the time to finally add a 10.6 partition to the drive, and noticed that Snow Leopard won't install on a non-GUID drive -- the Installer simply won't let you continue.

I can't afford to loose the ability to boot PowerPC systems like 10.3 or 10.4 or even the universal 10.5, so repartitioning as GUID was not an option here. Knowing that Intel versions of OS X will boot just fine (though officially unsupported) on APM-formatted drives, I solved this in a somewhat inelegant but effective way: I installed 10.6 on another drive with the GUID partition scheme, and simply cloned it back to an empty partition on my APM drive.

So for now, at least, I can still use one drive to boot all these systems: 10.3 PowerPC, 10.4 PowerPC, 10.4 Intel, 10.5 (Universal), 10.6 (Intel only, of course). Note that this might change in the future (10.7?), but for now, it works fine.

The latest version of the iPhone OS allows you to have 11 pages of 16 icons, plus the four permanent icons at the bottom of the screen, for a total of 180 apps. You can actually have more than 180, though only 180 icons will be visible.

To get to the invisible apps, just do a search (press Home from the home screen), and type part of the non-visible app's name. I don't know how many of these invisible apps you can have, as I have not tried more than three so far.

[robg adds: As far as I know, the limit is simply based on the available space on your device. Long before that point, though, you may run into a limit with your ability to remember the names of all the invisible apps.]

After upgrading from 10.5.8 to 10.6.1 on my MacBook Pro, I was unable to connect to wireless networks unless I had already connected to them running under 10.5.8. Snow Leopard would "see" the new networks, but could not connect to them.

The Genius Bar at the Apple Store helped me solve the problem. We opened Library » Preferences » SystemConfiguration, and trashed the entire contents of that folder. We also deleted all locations in System Preferences » Network, and recreated the location Automatic. Finally, we rebooted.

So far, I have been able to connect to all wireless networks that I want to using OS X 10.6.1.

One of the "features" in Apple's Mail program that has always annoyed me is how it handles messages after doing a delete operation. If you press Delete to throw away the message you're currently looking at, Mail displays the next message (marking it read in the process). While I like the fact that Mail marks displayed messages as read, I have always found it annoying that it displays a message that I have not specifically selected (and then marks it as read).

There's a way around this. Instead of pressing Delete, press Option-Delete. With this shortcut (which doesn't show up in the Edit menu), Mail deletes the currently-displayed message and then does nothing at all, and the next message is not displayed. This is exactly what I want -- I now must explicitly tell Mail when I want a message to be displayed.

I expect I can make this the default using the Keyboard Shortcuts tab in the Keyboard System Preferences panel, but I have yet to play with that.

[robg adds: It doesn't appear you can change the shortcut for Delete to Option-Delete, because OS X won't let you use the Delete key as part of a shortcut.]

Within the Desktop & Screen Saver System Preferences pane, pressing Command-Option-D (Show/Hide Dock shortcut) will add two new buttons to the panel: TEST and DEBUG WINDOW. Press Command-Option-D again to remove the buttons.

TEST doesn't seem to do anything, but DEBUG WINDOW displays a window that gives you debug information about the current desktop picture.

[robg adds: I'm not sure why this info might be useful; it's very low-level stuff, such as the value for configManager.operationQueue.operations. I'd guess that a bit of development code got left in the final release, and I expect it will be disappearing in a future point update.]

When I'm working anywhere in 10.6 other than in the Finder, I might suddenly need to go to some path. It kind of bothers me that I have to Command-Tab to the Finder, and then do the Shift-Command-G keystroke. Also, I might want to open some Macintosh-style path (:) instead of POSIX-style (/) path.

Now, in 10.6, I can jump to a path using a Service. Here is a basic intro:

1. Open Automator and choose Service from the Templates chooser.
2. Make sure the Service receives "no input" in the pop-up menu at the top. Drag the Run AppleScript Action (in the Utilities Library), into the work area on the right, and enter this AppleScript in the Run AppleScript box:

   --Go to POSIX
   on run {input, parameters}
     tell application "Finder"
       set myName to (name of home) -- get your user name
     end tell
     set myPosix to (text returned of (display dialog "Enter a POSIX Path to jump to:" default answer "/Users/" & myName & "/Desktop/"))
     set myCommand to "open '" & myPosix & "'"
     do shell script myCommand
     end run

   If you prefer to user Macintosh-style paths, you can replace the set myCommand... and do shell script... lines above with just one line: set myCommand to (open alias myPosix)
3. Save your Service with a relevant name (Go to Path or whatever), and quit Automator.

You can then assign your new Service a keyboard shortcut on the Keyboard Shortcuts tab of the Keyboard System Preferences panel.

[robg adds: I tested the POSIX path version of the script, and it worked as described.]

Git is a very popular distributed version control system. You can use it to track versions of files in your project and collaborate with other project participants in very sophisticated ways. To learn Git, I'd recommend Scott Chacon's Pro Git book (free online, or buy a printed version). You can use Git on your local computer, but if you want to access it from multiple computers with Git installed, MobileMe can be handly.

Your MobileMe disk space is available via the WebDav protocol, which Git can also use. Here are the steps to create a repository on MobileMe. First, if you use Git from MacPorts, chances are that Git on your machine uses a version of curl without SSL support. In Terminal, use the following command to check:

$ port installed curl

If that does not list +ssl in the curl options, reinstall it by typing sudo port install curl +ssl. Once that's done, you're ready to set up your repository.

After restoring from a Time Machine backup, I ran into this error when Time Machine then tried to create a new backup:

The backup is too large for the backup volume. xxGB is required but only yyGB is available.

This occurs because Time Machine sees your restored computer as a completely new set of data and is trying to do a full back up. To solve this issue, open the backup drive that Time Machine backs up to, and locate the following file:

computername_0022334455.sparsebundle

Where computername is your computer's name, and 0022334455 is your computer's MAC address. Delete this file and have Time Machine do a new full backup of your system, and this error will disappear.

[robg adds: I've never had to do a full restore from Time Machine, so I haven't seen this error -- if someone else can confirm the problem and the fix, please post in the comments.]

Java on MacOS X 10.6 has some problems with certain timezones. This problem only affects Java programs, but will cause any Java programs to use incorrect dates. For example, any cities/towns/villages in southern Ontario (locations using "America/Toronto") will find their Java apps reporting an offset of five minutes behind GMT.

The solution is to explicitly specify an alternative location that doesn't have problems. For those in southern Ontario, Montreal works fine. To see if you have this problem, perform the following steps:

1. Copy the following text to a file called tz.java in your home directory:

   class tz {
     public static void main(String[] args) {
       java.util.TimeZone tz = java.util.TimeZone.getDefault();
       System.out.println("Timezone offset from UTC reported as " +
   	(tz.getRawOffset() / 1000 / 60) + " minutes");
       if(tz.getRawOffset() % (15 * 60 * 1000) != 0) {
   	System.out.println("Warning: not a multiple of quarter-hours");
       }
       System.out.println(new java.util.Date());
       System.out.println(tz);
     }
   }
   

2. javac tz.java

I would be surprised if this really is a new hint, but I can't find anything on the subject from searching Mac OS X hints. The closest hint is similar, though, as it refers to changing iTunes' volume by using a scroll wheel mouse.

Whilst a song is playing in iTunes, position the mouse pointer anywhere over the display element that contains the current position of the song (i.e. the long thin gray bar between the 'time elapsed' and 'time remaining' counters). You can now use the scroll wheel of your mouse (or scroll with a track pad) to scrub backwards or forwards through the song.

This technique allows for some precision playback adjustment. One 'click' on the scroll wheel of my Logitech trackball seems to adjust the playing time by less than a second. This hint also works in the miniature iTunes window.