Recently I saw an article on DarwinX86 (French site), and for sure they do not read my site finally they did ^^. So I'm posting this article just to make sure everyone understand what's the best alternative to HDAPM. If you don't know what I'm speaking about, just read this article: Is your Hard Drive making *Clunk* noises?

So now let me explain how does my ClunKiller 1.2 version work...

When you install ClunKiller, a daemon is launched after every boot. The program is located into your /Library/StartupItems/ClunKiller folder and there are 2 main scripts for it.

• Thireus_Trace: This one enables dtrace and reports every 2sec the amount of data your main drive write & read.
• ClunKiller_shell: This is the script that receives the Thireus_Trace information, analyse them, and decide if it is needed or not to launch the sync command.

What is sync?

Basically it's a flushing command that asks your drive to write all cached data on the hard drive. And what is great with this command, is that when there is nothing cached it keeps the drive alive without writing anything on it. The sync command is launched every 5sec if the drive is idle to keep it alive without reading nor writing on it!

By default you can see on your Mac a "update" process that is launched after boot and that does a sync task every 30sec (Google that if you don't trust me). ClunKiller kills this process and provide another kind of flushing system that kills clunks at the same time .

Why don't you use a script that writes on the drive to keep it alive?

First of all, this is really bad to write on the drive every 5sec. Why? There are many reasons!

• The drive is making noise when you write on it.
• On some computers if you write on the drive your computer cannot go to sleep.
• The drive never stops to write almost at the same place, thus it shorten your hard disk life.

Why do you use a tracing script?

Optimize!!! If you ask the drive to write or flush your data when it is still writing or reading you can interfere with its performances! The tracing script only use about 0.02% of my 1.6ghz cpu to calculate the i/o amount of data, so this is greatly optimized!

Why 5sec?

Because this is the most common Hard Drive APM timer before the head goes parked. So every 5sec you need to wake the drive before parckage.

Why do you unload the update script?

Because it does exactly what the sync command does

ClunKiller does not work for me, why?

You need a file called mach_kernel.ctfsys into your / directory to make dtrace working. If you do not have this file, try to ask people who have the same computer/OS/kernel that you use.

This is mine: mach_kernel.ctfsys.zip (But I think it will not work for you)

Try "mach_kernel.ctfsys dtrace" on Google.

If you have this file and you can still hear some *clunk* noises time to time, then I'm afraid to tell you that you need a better Hard Drive.

What about your Hard Drive?

My previous Hard Drive was a ST9160827AS (Google that). But ClunKiller was not working nicely with it (clunks were still there time to time, maybe every 20min) and HDAPM was not working. Then, because I was sure my ClunKiller application will work with a better Hard Drive I bought an ultra fast Hard Drive WD3200BEKT (Google that too). HDAPM was still not working with it and clunks were still there every 5sec just like the previous HD, thus I've installed my ClunKiller app, and guess what? The last *clunk* noise occurred a month ago .

The drive is still very very fast (eeepc 1000H bench) --> http://thireus.dareyourmind.net/xbench_10.5.8_Thireus.txt

Do you have the same results with your 2.5'' Hard Drive? ^^

Ok, nice there is no more clunk. But is it safe?

It depends on how your APM gesture works. On my hackintosh the APM is very bad, I mean the hard drive cannot park the head correctly. The head just hits the parking area! So it is useless to keep these *clunk* noises occur. To know more about it, please read the comments at the end of this page: Is your Hard Drive making *Clunk* noises?

Why do you share two different versions?

The first version is the optimized version. The second one (Mac Mini version) is a simple writing on drive version. Yes I said it's very bad to write on the drive every 5sec, but some people can't get the usual version to work... so this is maybe better for them to kill clunks this way because this is the only alternative they can use.