While compiling a piece of software from source the other day, I noticed that my CPU was only at about 50% utilization.  This reminded me that the build tools can be set to execute multiple operations simultaneously.

The CONCURRENCY_LEVEL environment variable is used by many tools to determine the number of concurrent jobs to run:

 export CONCURRENCY_LEVEL=3

 It is also possible to tell "make" directly how many simultaneous jobs to run:

 make -j 3

 make --jobs=3

 On a sample dual-core system, this improved my emacs compile time from 2m36s to 1m31s.

Probably no surprise to anyone, my home desktop computer runs Linux.



I recently posted Heatsink Bracket and Clips for new CPU cooler so I thought I ought to post more details about that system.


Here are the specs:

This Zalman is too loud:



Here is the funky bracket the Zalman uses:

I'm sure that other sites will do a better job of reviewing the Droid in-depth, so I will just give some impressions and post a few pictures.

Here are the first pics (note: Jabba is not to scale):

The Droid sitting next to my semi-ancient work-provided BlackBerry:

A few weeks ago I bought my first netbook, an Acer Aspire One AO751h.  Today these are selling at NewEgg and elsewhere for under $300, but if you intend to run Linux today you should try a different model.

** Update June 2011:  The AO751h really sucks at running Linux.  I continued having the issue where it would not resume from suspend every time, sometimes wireless would not re-activate, etc.  Eventually I put Windows back on it and gave it to my brother. **

I wanted a netbook because it would be light enough to take "everywhere" and due to cost. Ultra-light notebook computers are still over $1000 which is more than I wanted to spend.  I chose the AO751h because the case comes in various non-generic colors (I chose blue), it has a nice big keyboard, long battery life, and the screen is 11.6 inches with a resolution of 1366x768.  The large hard drive (250 GB) allowed me to double- and triple-boot while I tested various Linux distributions.  This netbook is great for web browsing, running vim/emacs, SSH, git, and Remote Desktop. I bought the Windows Vista version of this netbook in order to get the included 2 GB of RAM.  The AO751h includes a 6-cell battery and lies flat on the table, unlike some of the netbooks that have an ugly battery sticking out the bottom that raises the back of the netbook up.  I need proper ergonomic keyboard angle to help avoid wrist problems.  I plan to do a lot of typing on this computer.

Sadly, the AO751h and Ubuntu are not yet a match made in heaven.  After some struggle, I did manage to get a usable Ubuntu 9.04 system,  Enough quirks remain that I continue to dual-boot with Windows.  Windows Vista was very slow on this hardware, so I replaced Vista with Windows XP which runs very well.

Here is the Ubuntu wiki page for this system:

https://help.ubuntu.com/community/AspireOne/AO751h

There are two major Ubuntu compatibility issues with this hardware that require tweaking... the video resolution and Suspend/Resume.  Wireless works out of the box although sometimes the device takes over 15 seconds to re-activate after Resume (and occasionaly wireless never comes back and I have to reboot).  The function keys for brightness do not work in a fresh install but seem to work ok after installing the psb-kernel-source package for the Intel Poulsbo (GMA 500) graphics.

Detailed hardware info (including lspci output) is at the bottom of this post.