The 500XL Desktop Earbud Speakers are 500 times the size of the stock earbuds that come with iPods but are otherwise identical (though a version old.) While I’m not about to replace my new Klipsch desktop speakers these would look great next to my iMac!
So I finally took the plunge and bought a new 20″ Apple iMac. I’ve got to say I love the machine in all its glass and aluminum glory, but I can’t let this transition pass without paying a little homage to my 400MHz Mac G4 tower that has served me so well for so long.
I bought this machine in January of 2000 (my senior year of college.) It has run essentially nonstop since then at any time carrying out some or all of the following duties at any given time:
- Ethernet router
- Wirless router
- Web server (with dynamic DNS)
- UNIX development machine
- MIDI workstation
- Editing short movies
- Rendering of POV-Ray images for Tom
- Countless MAME games
The system came with a 10GB hard drive which I immediately upgraded to 36GB. The initial 128MB of RAM was removed to make way for a couple 512MB chips giving the system a full gigabyte of RAM. Though this mac originally came with Mac OS 9 I was able to upgrade it to OS X, even 10.4 without any problems. Now I don’t mean it ran part of 10.4 or it was in any way crippled. This 7+ year old machine runs the latest OS just fine.
The decision to replace the machine came for two reasons. One, I wanted a machine I could hook up to my TV. Two, when working with large files (high resolution movies and pics from my 7 MP camera) things really slowed down. It was also time for a bit more hard drive space.
So with over 7 years of runtime with, by the way, no maintenance required I can happily retire this old G4 and honestly say it owes me nothing. I only hope the new iMac does just as well.
If you’ve spent much time working in a UNIX environment you’ve probably seen the load averages more than a few times.
load averages: 2.43, 2.96, 3.41
I have to admit that even in my sysadmin days I didn’t fully understand what these numbers were, but Zach did some digging a while ago to try to understand where these numbers are comming from.
In his blog entry from late last year, Zach sums it up quite nicely:
In short it is the average sum of the number of processes waiting in the run-queue plus the number currently executing over 1, 5, and 15 minute time periods.
The formula is a bit more complicated than that, but this serves well as a functional definition. Zach provides a bit more detail in his article and also points out Dr. Neil Gunther’s article on the topic which has as much depth on the topic as anyone could ever ask.
So what does this mean about your system?
Well, for a quick example let’s consider the output below. The load average of a system can typically be found by running
uptime and users typically don’t need any special privileges for these commands.
load averages: 2.43, 2.96, 3.41
Here we see the one minute load average is 2.43, five minute is 2.96, and fifteen minute load average is 3.41.
Here are some conclusions we can draw from this.
- On average, over the past one minute there have been 2.43 processes running or waiting for a resource
- Overall the load is on a down-trend since the average number of processes running or waiting in the past minute (2.43) is lower than the average running or waiting over the past 5 minutes (2.96) and 15 minutes (3.41)
- This system is busy, but we cannot conclude how busy solely from load averages.
It is important here to mention that the load average does not take into account the number of processes. Another critical detail is that processes could be waiting for any number of things including CPU, disk, or network.
So what we do know is that a system that has a load average significantly higher than the number of CPUs is probably pretty busy, or bogged down by some bottleneck. Conversely a system which has a load average significantly lower than the number of CPUs is probably doing just fine.
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