While I was within Safari, I was showing someone what the expand gesture was like for iPhoto, and discovered that the new trackpads resize the page font using that same gesture. Further investigation found that Mail does the same thing, and Preview resizes the whole page/photo.

[robg adds: According to a friend with a new laptop, the Preview zoom feature is shown in one of the how-to-use videos for gestures, but the font resizing functions are not. If this turns out to be clearly documented somewhere, please let me know and I'll remove the hint...]

With the latest laptop models that supports three-fingered scrolling, if you use three fingers on your trackpad and move either up/down or left/right, you can move to the next (or previous) Mail message in the current listing that you are viewing. This makes for an easy way of moving through mail -- lift a finger to scroll the message content, then put it back down and move your fingers to go to the next message.

The new keyboard found on MacBooks and MacBook Pros now contain Dashboard, Exposé, and media controls on the function keys, but removed the toggle between mirror mode and extended desktop mode. On the prior keyboards, the toggle display mode function was located on the F7 key.

On the new keyboards, you toggle display modes by pressing Command-F1. This only seems to work from the built-in laptop keyboard.

[robg adds: From the "coming full circle" department, this behavior existed way back in 2002, then apparently was either forgotten about or disabled on newer laptops, only to make a return on the new models. I'm running this one now because the keyboard layout on the new machines lacks the mirror function on F7, so you may not think to try (nor perhaps be able to find) a 2002 hint as the solution.]

I have been wondering where gestures (on the MacBook Air and new MacBook Pros) can work and how, so I've tried gestures in many apps, including QuickTime Player. If you use the "make bigger" pinch gesture on an open movie, it goes full screen. If you do the opposite "make smaller" gesture, the movie goes back to windowed mode. Pretty handy for those of us who need to work with many clips and movies.

When I got my PowerBook, I noticed it got ridiculously hot when using it under normal load. This is because the fans don't turn on until the machine gets really, really hot. A program called G4FanControl can help with that problem.

The GUI version runs under Leopard, but requires you to run it every time you log in, and enter your password. Once you do this, you also have to re-set your temperatures, because the app does not remember them. I found a way to work around this problem -- this earlier hint suggested a fix to this, but didn't give any code. After a couple of hours, I finally figured out how to do this (I had to learn how to make the script).

Things you will need for this:

• The command line version of G4FanControl (version 0.4) -- download link
• Lingon by Peter Borg.

Many PowerBook G4 users are experiencing failures of the lower memory slot. I have found a workaround for the problem, though not quite a full solution (as it won't survive a reboot). Note that very little testing has been done on this fix, but I have used it on my PowerBook with 100% success.

First, I confirmed my lower slot is not fried by starting up with a single DIMM in the lower slot, which worked. However, the Mac still will not recognize the lower DIMM if there is memory in both the upper and lower slots. This may be different to what others are experiencing so your mileage may vary.

[robg adds: Note that this hint involves the use of Open Firmware, and you could permanently damage your machine by following this procedure. Proceed at your own risk, as macosxhints.com will not be held liable for any damages you cause to your own machine.

I was on the fence on running this hint, but when I ran the Google search linked above, it seems this is a somewhat widespread issue...and maybe this will help someone get back some currently unusable RAM. Just keep in mind you could also really damage your Mac when working in Open Firmware.

Read on for this user's workaround to the memory slot recognition issue...]

To speed up system installation on the MacBook Air, create a disk image (in Disk Utility) of the Air's Install disks (both of them), and save them locally on your DVD-equipped Mac. Spit out the real DVDs, and open both the disk images. The Remote Install Mac OS X application (in Utilities) can serve these to the MacBook Air much faster than directly from the DVD. As an example, a full install took about 15 minutes, instead of the normal hour for a fresh install using the DVDs.

I also used the ethernet cable on the MBA, and connected it straight into the Ethernet port of the Mac that was serving. That machine was connected to the net by AirPort, so I set the 'Share Internet Connection' optionto "from AirPort to Ethernet" on that box, so that the MacBook Air pulled files from it directly. Woooosh!

[robg adds: If someone sends me a MacBook Air, I'll give this hint a thorough test...]

I'm surprised this one hasn't come up earlier, actually. I recently purchased a 4GB Techworks upgrade kit for my previous-generation (2.33GHz) 17" MacBook Pro. From what I'd read, due to either limitations in the Intel logic board, or limitations in the EFI firmware, I'd only be able to access 3.3GB of it.

Not so. Running 10.5.1 Leopard, after installing the RAM, I found I could address all 4GB of it. As seen in both System Profiler and Activity Monitor, I have the full 4GB available, running in dual-channel mode.

Third-party SO-DIMM RAM is cheaper than ever at the moment, so previous-gen MacBook Pro owners who've installed Leopard have no excuse but to upgrade now, really.

[robg adds: I can't confirm this one, but MacTracker lists 3GB as the RAM limit for the 2.33GHz 17" machine. If you have 4GB of usable RAM in some other previous-generation MacBook Pro, please post in the comments...]

Update: Please read the comment below (by macavenger) for the full story on the RAM expansion limits. I've left this one comment and cleaned up all the rest, so that anyone searching can easily see the proper explanation.]

If you have two-finger trackpad tap set to function as a secondary click, you can also just hold two fingers down on the trackpad and click the track button for a secondary click. This works in 10.5 Intel and PowerPC. I'm not sure if it works in 10.4, but I'm guessing it will work fine on Intel and PowerPC.

[robg adds: This method of clicking can be useful if you're using two fingers to scroll; you don't have to lift them and then tap when you want a contextual menu. Just click the mouse button with the fingers still on the pad, and you'll get a control-click.]

We have a G4 iBook running 10.3.9 that has been running extremely sluggish and very hot -- too hot to rest your hand on the lower left corner. A visit to the Activity Monitor confirmed 100% CPU usage, and the culprit was a process named fsck_msdos. This had me confused: I know what fsck does (it verifies and fixes disk volumes), but I do not have a FAT-formatted volume connected.

Further experimentation led me to a defective CF card. Apparently, when diskarbitrationd attempts to mount the volume, it launches fsck_msdos. And fsck_msdos appears to be brain-dead: if it cannot access the volume, it just sits there and consumes CPU cycles...all of them, as long as the machine is on, whether or not you remove the defective card.

The solution is to simply kill fsck_msdos in the Activity Monitor, and read the defective card through the camera's USB interface. Surprisingly, a search of the Apple forums in the 10.3 discussion threads produced exactly one hit, which had nothing to do with the problem.