A Tasty Pixel » Geekspeak

AutoRate 1.4.2

Edit: Please see the official AutoRate product page for the latest version

Hot on the heels of 1.4.1, AutoRate 1.4.2 has just been released. It has a drawer instead of a separate preference pane, and the playlist selection has moved down there.

In addition, I’ve again tweaked the ratings – as there’s now a setting to select between play frequency and play counts, there appears to be little need for a log transform to hack the ratings (in fact, it caused problems for my library). So, it’s gone – let me know how it goes.

AutoRate 1.4.1

Edit: Please see the official AutoRate product page for the latest version

I’ve released version 1.4.1 of AutoRate, which now has the option to use just play counts to generate ratings, or a variable mixture of play counts and play frequencies.

As the use of play frequencies tends to bias towards new tracks (which have a high play average, as the track age is small), and the use of play counts tends to bias towards older tracks (which will have a higher play count because they are older), I’m hoping a combination of both techniques may lead towards fairer rating.

There’re also a few tweaks to the way that track skips are factored in to the rating, and the option to select how much effect the previous track rating has on the new rating.

Creating applications in XCode using frameworks

Defining a proper, logical structure to a new project is an important early step. It will save time later, when you realise you really need to enforce a bit of order, and will make development easier over the life span of the project.

One useful structure that can be fairly well managed in XCode makes use of frameworks to contain the bulk of your project’s code. A framework can be created as a ‘sub-project’, and a build step added to your main target that builds the framework before continuing. This can aid in enhancing the readability and maintainability of your code, and helps to encourage and enforce the use of the model-view-controller paradigm.

Run-down on Mac OS X media center software

Update: Matt Hansson has written a more up-to-date overview of the offerings. His findings: He still prefers Mediaportal on Windows to the currently available Mac solutions. Damn.

We’ve recently set up a home entertainment centre, consisting of a 40″ Samsung LCD TV, a Yamaha 6.1 audio setup and a Mac Mini.

In order to drive it all, I was after a full-screen media center suite (movies, music, DVD, etc), to hide the fact that it’s a computer – we don’t wanna see that muck!

It had to have a high usability, and a high WAF (Wife Acceptance Factor…Actually, partner, but you know), which means no hardcore key combinations, or dropping to terminal to kill -9 anything. I’m looking at you, Xhub.

It had to be relatively fast – no waiting around for five minutes for the music library to appear.

…And it had to offer some moderately easy way to share screen-time with EyeTV, the digital TV viewer/recorder.

OS X performance tweak?

While looking around for information on some fairly irritating memory leaks I’ve been encountering in OS X (some common library seems to be chewing up memory, so that after a few days of running, all my apps take up enormous amounts of memory), I found this old tip regarding setting the maxvnodes parameter.

A comment attached to the tip above quotes one of Apple’s kernel developers: “Increasing the value of maxvnodes will increase the number of files that get cached in RAM. This will make subsequent access to those files much faster. But the downside is that more of your RAM will be used up for this disk caching and thus you will have less RAM available for normal application use.”

Thus, by default, Apple specify a value that is apparently a compromise for best overall performance.

That said, I increased the value to 84672, despite not having large amounts of free RAM:

sudo sysctl -w kern.maxvnodes=84672

My machine, after running for a few days without a reboot, often runs quite sluggishly, with lots of swap activity. For example, bringing up the Dashboard after not using it for a while can take a good 5-15 seconds, depending on what else is running.

After tweaking the maxvnodes value, all the widgets in Dashboard refreshed within 2 seconds (it had been a fair while since I last brought it up) – just coincidence, or did it actually make a difference?

The system does feel snappier; I can do things like start apps, bring up menus, load webpages, switch desktops and use Quicksilver without the irritating delay that I usually get. Maybe it’s all in my head, but maybe not. Worth a go!

If it does work, the command can be put into /etc/rc to be run on boot (as settings are forgotten after reboot). Instructions are outlined in the comments accompanying the tip.

[Edit]: This command might aid in establishing an optimal value:

sysctl -w kern.maxvnodes=$(echo $(sysctl -n hw.physmem) \
   '33554432 / 512 * 1024 +p'|dc)

Mail’s ‘Entire Message’ search gives ‘0 found’

Mail just stopped returning search results when I did a full text email search. I did a bit of googling and found some discussion on the problem with 10.4.7 that was fixed with 10.4.8. So, not that. Someone in that thread mentioned that they forced a re-index of their entire drive in Spotlight.

Scott, another individual who mentioned the problem on his blog said he attempted to just re-index the local Mail repository, but to no avail (he noted that there was a problem with the Spotlight filter for Mail). He also forced a rescan of the drive.

I didn’t feel like doing an entire rescan, so I checked for the Spotlight filter with mdimport -L. Lucky for me, the Mail importer seemed to show up. I quit Mail, re-indexed its data with mdimport -f ~/Library/Mail, waited a few minutes and re-opened Mail to find search working again.

So, just forcing a re-index of the Mail directory seems to work under 10.4.8 Intel.

Incremental rsync backups

I’ve written a shell script to do incremental backups with rsync (inspired by this macosxhints article).

The script takes one or more sources, and a local destination path, and creates an incremental rsync mirror at the destination. It will first create an initial archive, then will subsequently create a new archive, hard-link the last archive in, and perform an rsync over it. Each archive will appear to be a full mirror, but will actually only use the disk space of the files that have changed, due to the use of hard links.

Here’s the script:

incremental_rsync.sh

And some uses of it:

incremental_rsync.sh [email protected]:www /Volumes/BackupDrive/Web incremental_rsync.sh Documents Pictures Library /Volumes/BackupDrive/Home

Note that old backups can be safely deleted without disturbing more recent backups; as hard links are used, the data won’t be deleted until all links that reference it are removed.