21 August 2009

Multithread or Multicore?

In order to install iDeneb on the HP Mini 1000, you have to enable the "CPUs=1" fix option or else the install will fail to boot up, leaving you scratching your head and perhaps enunciating not so pleasant words directed to the how-to-guide authors; they said it would work in the first place.


So this option specifically tells OS X that your HP Mini has only one core. Now what I'm actually perplexed about are people hacking the com.apple.Boot.plist to take out that key and string that the "CPUs=1" fix has put in there so that the HP Mini's "2 cores" will be recognized again.


1) Go to /System/Library/Preferences/SystemConfiguration and open com.apple.Boot.plist with your preferred plist editor or even just TextEdit.
2) Take out these lines:

<>Kernel Flags< /key>
<>cpus=1 -f< /string>



Beatrix said...


hi instead of removing those two lines? replace it with =2 on cpus like this
<>cpus=2 -f< /string>
this will prevent it from having the startup problems. :D



so your Boot plist file should look something like this:


3) Save the file. If you're using only TextEdit, you may need to save the file somewhere else for a while, on your Desktop perhaps, then copy paste it to /System/Library/Preferences/SystemConfiguration to replace the original file. Also, you may need to rename it in order to reinstate the ".plist" extension which disappeared in my case when I tried to do this.
I did that myself. I also believed that my 1.6 GHz Atom N270 had 2 cores indeed. I had thought it was just capable of multithreading. And then just to verify, I checked Activity Monitor:



I was quite skeptical and so I did a quick googling and pulled out my HP Mini's CPU's spec sheet straight from Intel's site and saw this:



I couldn't see any "dual core" option there. Some more googling about the CPU=1 pointed me to netkas' CPU-X which I downloaded within minutes and here's what it told me about my CPU:



So that means, I've 1 Processor with 1 Core and 2 Threads. What gives? I do know for a fact that before I took out the "CPUs=1" key from my com.apple.Boot.plist, Activity Monitor would only show one cpu.


But then again, after doing that com.apple.Boot.plist exercise, CPU-X tells me I have only 1 core. . .oh well.



3 comments:

Anonymous said...

The Intel Atom N270 is a single core processor, but Hyper-Threaded. That means the one physical core is split into two virtual cores. It's much more complicated than that (search wiki), but that's why you see only 1 processor, but 2 threads. If you look at the new Intel i7 processors, they have 4 physical cores, but 8 threads.

Beatrix said...

hi instead of removing those two lines? replace it with =2 on cpus like this
<>cpus=2 -f< /string>
this will prevent it from having the startup problems. :D

LeMaurien19 said...

Thanks for that tip! :D