Archive for March, 2009

28th March

Frying tonight.

written by Mark Wheadon

Frying tonightFish courtesy of Kurt Koller (live) and f10n4 (battered). Cartoon available under this Creative Commons Licence.

22nd March

VMWare’s Fusion can lead to slow, large Time machine backups.

written by Mark Wheadon

[This almost certainly applies to most other virtual PC packages as well, so if you’re using Parallels Desktop for example, read on… –Mark]

Are you using the excellent VMware Fusion and backing up your Mac with Time Machine? If so, you may notice a problem.

Large backups

When you’ve been using Fusion‘s virtual machine (in my case, to run Windows), you will find that Time Machine‘s next backup takes longer than expected — sometimes much longer.

This is because Fusion stores its virtual machines’ disks as a bunch of large files. When you run your virtual machine using Fusion, the contents of the VM’s virtual disk changes, and even if you haven’t made many explicit changes to files, all sorts of small changes happen to the virtual disk’s contents.

Incremental can still be too much

Time Machine performs incremental backups. That is, it copies only files that have changed since the last backup. Unfortunately those large files that Fusion uses to store the virtual disk’s contents? They’ve probably all changed, at least a little.

backupSo, instead of your incremental being a few megabytes and taking a few tens of seconds, it’s ten gigabytes, takes ages, and rapidly fills your backup disk. (Which causes its own problems: described here.)

An alternative fix

If you need incremental backups of your VMs, or your VMs are running an operating system that doesn’t have support for accessing theMac OS file-store (Linux, for example), then you’ll likely find this approach is the best for you.

If your VM(s) are running Windows (so you can access the Mac OS file-store from within the VM) and you don’t need a sophisticated incremental backup of your VMs then read on, as the following approach produces by far the most efficient backups.

This fix

The fix described here is to ensure the files you edit in Fusion‘s virtual world are in the Mac’s natural file-store (so they continue to be backed up by Time Machine), stop using Time Machine to back up your virtual machines, and then back up your virtual machines in a different way. I’ll cover each of these steps in turn below.

Put your files somewhere safe

Instead of putting your Windows (or whatever) files in the Windows file-store, place them in the Mac’s file-store (which is available to Windows as the Z: drive by default). This means that your precious files have a proper, incremental backup using Time Machine, and you can restore earlier versions should the need arise.

Stop Time Machine backing up your VMs

Open Time Machine Preferences…, click on Options… and then the small + to add a Folder to the Do not back up list:

add-folderThen navigate to Documents below your home directory and there you will find a folder called Virtual Machines — add that and Time Machine will no longer backup your Fusion VMs.

And backup your VMs in a different way

copying-vm-to-backupIf, like me, your virtual machine is a secondary system, then you probably have no need of an incremental, sophisticated backup. What’s important is the files you edit are protected, and they are now protected by Time Machine as part of the Mac’s natural file-store.

So, simply drag your Documents/Virtual Machines folder onto the backup drive every week or so, and you’re sorted.


As with any method of backup which relies on backing up the virtual machine’s disk image using the host operating system, your backup may not be of any use if it’s made whilst the VM is running, so I suggest you make sure that Fusion/Parallels is not running when you copy the data.


Because if you copy the files that Fusion (or Parallels) is using for a disk image, then you’re backing up what’s on disk, but not what’s in memory, in disk buffers, etc. So when you come to restore from backup, you may find that the disk image is corrupted. In the worst case scenario you won’t be able to start up the VM’s operating system successfully at all, or restore any files contained within the VM’s file-store.

By backing up when the VM isn’t running, you ensure that all data is on disk in a safe, consistent state.

17th March

Want to use Safari 4, but put off by the visual editor not working in wordpress? Here’s a fix.

written by Mark Wheadon

All change

As of the the 8th June 2009, Safari 4 is out of beta, and wordpress‘s insert-link dialogue works! So this article is now superfluous — good stuff.

I’ll leave the article here to help clarify what WebKit is and how to use it, but if you’re looking to get wordpress‘s insert-hyperlink dialogue working with Safari 4beta then all you need do is download the full release version of Safari 4 from Apple’s site.

And now for the original article…


15th March

How to make Time Machine backup less (or more) frequently.

written by Mark Wheadon

Apple’s Time Machine is a useful beast. Plug a disk into your Mac or buy a Time Capsule and Time Machine does the rest — waking up once an hour and copying anything that’s changed onto your backup.

However, you may not want a backup every hour — the backup disk is a limited resource. If you’re regularly changing large files then Time Machine is regularly writing large amounts of data to the backup disk, and if that’s the case then you won’t have backups going back very far into the past.

So there will be lots of revisions of files that have changed recently, but nothing much from, say, a couple of months ago.

So how do you change the interval?

The standard Time Machine options don’t allow you to change the backup interval (the time between backups), but the preferences are there to be changed if you know how.

From the command line

If you don’t want to install any extra software then you can change Time Machine‘s backup interval from a shell prompt. Start up a Terminal window and then type:

sudo defaults write /System/Library/LaunchDaemons/ StartInterval -int 18000

The 18000 above is the required backup interval in seconds — five hours in this example. And note that the above command is all on one line.


There are several full Mac OS applications out there that allow you to manipulate Time Machine‘s hidden preferences. The two most popular are Time Machine Scheduler and Time Machine Editor. I haven’t used either (being someone who leans toward using the command line), but they look like they’ll do the job. However…

My recommendation was, but is no more:

I did suggest using the Secrets prefPane to change Time Machine‘s backup interval (see below), but unfortunately that turned out to be bad advice. You can set the interval using the Secrets prefPane but it doesn’t stick. Quit the System Preferences application and start it up again and you’ll find the interval has gone back to the default of 3600 seconds.

So it seems Secrets prefPane doesn’t work for this after all! I’ll leave the rest of this article in place and perhaps someone will tell me when the problem’s fixed?

In the mean time, please use one of the options suggested above.

Here’s the rest of the original article, which at the moment doesn’t work: (more…)

11th March

Apple call it VoiceOver: the new iPod Shuffle talks.

written by Mark Wheadon

The new iPod shuffle makes the old one look bulky (which is an achievement 🙂 ), and this one talks to you. Cute.

Here’s an introductory tour of the new mini-beast. A couple of interesting facts that emerge from the video: the speech is different depending on whether you synchronize using iTunes under Mac OS X or Windows, so speech must be synthesized on the host computer not the iPod, and one gotcha: you can’t use anything other than the supplied headphones without an extra dongle.

7th March

XKCD in the round.

written by Mark Wheadon

XKCD in the roundXKCD:

Original images by mot the hoople are available here and here under a Creative Commons Licence, and so it follows that this work is available under the same licence.

1st March

How do you dump the screen in Mac OS X when you can’t reach for a hot-key-chord? The answer is grab.

written by Mark Wheadon

Mac OS X Leopard has a tool to dump all or part of the screen built into the desktop, with handy (if difficult to remember) hot key-chords:

  • cmd+shift+3 to dump the whole screen
  • cmd+shift+4 to select an area of the screen (then press space for a whole window).

However, there are times when the above won’t do. Typically, it’s when you’re already pressing keys to get the image you need — the key chord cmd+shift+4 isn’t going to work if you’re already holding down alt for example.

That’s where grab comes in — it’s what Mac users used before cmd+shift+3/4 came along, it’s still there, and it can dump the screen after a ten second delay.

So, start up grab. I use Spotlight to do that, so I type cmd+space grab:

spotlight grab

Then, to do the delayed screen dump, select Timed Screen from grab‘s Capture menu:

grab timed screen dump

You then have ten seconds to set up the screen as needed, and grab does the rest.

Then select File->Save As… to save the resulting tiff file, and you’re done.