Friday, October 30, 2009

Parallelism in PDQ

All so-called "analytic solvers" for queueing models, including PDQ, assume that the queueing system being modeled is in steady state. Steady state means that in the long run, the number of arrivals into a service facility, e.g., customers arriving at a grocery checkout, will be identical to the number of customers departing. Why is this important?

Wednesday, October 28, 2009

Googling Google + Linux

Honorary Guerrilla alumnus, GB, sent me a link to "How Google uses Linux" which, although it provides an interesting view inside The Goog's datacenter management, looks like it's supposed to be available only to LWN subscribers:
"The following subscription-only content has been made available to you by an LWN subscriber." Eh? 
Not wishing to let any cats out of their subscription bag, I checked with the editor and he said it's ok to blog the link.

It's a BRisk Wind That Blows No Good

OK, I admit it. I can't resist this "I told you so" moment:
  1. BRisk Management
  2. When BRisk Goes Bust
But that doesn't mean I'm happy about it. In fact, I'd much prefer it had not happened. In case you missed what I'm talking about, a 5000 lb chunk of the San Francisco Bay Bridge (not the Golden Gate) fell onto the upper deck last night. Several drivers narrowly avoided potentially fatal injuries as pieces fell onto their vehicles. That's 2 tons or 2268 kg of falling steel, folks!

San Francisco Bay Bridge closure parts on deck
Click for video at KTVU Channel 2

Apparently, it was from the same cracked steel "I-bar" (a hinged strut shaped like the link in a bicycle chain) that delayed traffic flow while it was repaired less than 2 months ago. This failure was supposedly due to vibration from the high winds that prevailed yesterday, not an earthquake. No comment on the quality of the steel.

Monday, October 26, 2009

This Apple Does Fall Far From The B-Tree

That old adage: the apple doesn't fall far from the tree, doesn't apply to Apple the corporation. According to ArsTechnica today, Apple abruptly abandoned its open-source project to port Sun's ZFS as the filesystem for Mac OS X, on October 23rd.

The speculation is that Sun licensing fees may have been viewed as a roadblock to adoption or possibly there are growing concerns that Oracle's acquisition of Sun could cause other problems. In the meantime, Apple is hiring engineers to build its own advanced filesystem, instead of adopting either ZFS or its Linux derivative BtrFS.

Monday, October 19, 2009

Is SCO Waiting for Godot?

Bankruptcy Judge Kevin Gross remarked in his recent ruling that ongoing SCO Group litigation attempts were like a bad version of Samuel Beckett's play, Waiting for Godot. The almost decade-long legal saga gained publicity in the FOSS community for targeting Linux as illegally containing licensed AT&T UNIX System V source code.

Thursday, October 15, 2009

Hadoop, MAA, ML, MR and Performance Data

Over the past few months, I've been attending a series of talks on machine learning (ML), sponsored by at the NASA Ames Research Center, with an eye to applying such things to gobs of computer performance data. Two pieces of technology that kept cropping up were Google MapReduce and Apache Hadoop.

Thursday, October 1, 2009

Final Guerrilla Class for 2009 in November

Seats are still available for the final Guerrilla Capacity Planning class of 2009 during November 16-20. All classes are held at our Larkspur Landing location. All 5 days of this class will be professionally videotaped for later online distribution. So, if you want to be digitally immortalized, better get on it.

Entrance Larkspur Landing hotel Pleasanton California
(Click on the image for details)

Who Will Succeed Hawking?

Now that he is 67 years old, it is Cambridge University policy that Stephen Hawking relinquish his title of Lucasian Professor of Mathematics and so, he resigned that post yesterday but he did not retire from Cambridge University. This event raises the question "Who will succeed him?"