Log

There's an interesting on-going series of articles on file system latency over at Brendan's Blog. Usually when system administrators look into I/O performance, we look at the I/O of the disks. This is usually fine for a rough estimate of raw disk performance, but there's a lot more going on between the actual application and the disk: buffers, cache, the file system, etc. Brendan goes into detail regarding these matters by examining I/O performance of a MySQL database at both the disk and file system level:

• Part 1
• Part 2
• Part 3
• Part 4

This company is going out of business because they put all their eggs in a very delicate and quite frankly evil basket:

BeamItDown Software and the iFlow Reader will cease operations as of May 31, 2011. We absolutely do not want to do this, but Apple has made it completely impossible for anyone but Apple to make a profit selling contemporary ebooks on any iOS device.

If you're a company, and you do this:

We bet everything on Apple and iOS and then Apple killed us by changing the rules in the middle of the game.

you need to have your head examined :-) This is not the first time this has happened, and it will most certainly not be the last time. Apple will do anything it can to make a buck over other company's back!

Not just the company is being royally screwed over by Apple:

Many of you have purchased books and would like to keep them. You may still be able to read them using iFlow Reader although we cannot guarantee that it will work beyond May 31, 2011 [...] your computer which will let you access them with Adobe Digital Editions or any other ebook application that is compatible with Adobe DRM protected epubs.

So iFlowReader's have probably also lost all their ebooks because they had DRM on them. DRM (Digital Rights Management) is a technology which restricts media to a certain application or device; opening it in third-party applications is usually impossible.

And that's why I have never and will never buy an Apple product, or use any media that is DRM protected.

Lecture notes on the work of Einstein and physics inspired by Einstein's work:

The course is aimed at people who have a strong sense that what Einstein did changed everything. However they do not know enough physics to understand what he did and why it was so important. The course presents just enough of Einstein's physics to give students an independent sense of what he achieved and what he did not achieve.

Interesting article over at Linuxconfig.org:

This article describes a simple way on how to create a home made debian package and include it into a local package repository. Although we could use a existing Debian/Ubuntu package, we will start from scratch by creating our own minimalistic unofficial debian package. Once our package is ready, we will include it into our local package repository. This article illustrates very simplistic approach of creating debian package, however it may serve as a template in many different scenarios.

It's only logical, but I hadn't really thought about it much. Turns out Regular Expression can be vulnerable to external Denial of Service attacks.

Lessons on development of 64-bit C/C++ applications:

The course is devoted to creation of 64-bit applications in C/C++ language and is intended for the Windows developers who use Visual Studio 2005/2008/2010 environment. Developers working with other 64-bit operating systems will learn much interesting as well. The course will consider all the steps of creating a new safe 64-bit application or migrating the existing 32-bit code to a 64-bit system.

I have a laptop that travels with me to work as well as being used at home. I have a number of network CIFS mounts that I like to have available when I am at home, so I have them set to "auto" in /etc/fstab. [...] The problem is that when I shift locations, I need proper handling of those network mounts.

Handling network mounts on a very mobile laptop.

ArchFS is a FUSE (user-space, so it does not require a special kernel module, other than the FUSE kernel module) file system on top of rdiff-backup (an incremental backup tool). It allows you to mount a rdiff-backup repository and then provides an easy way to maneuver through the various revisions in that repository.

We started a new site where we can vent our rage on all things sucky about software:

Software Bashing: We hate software. With a passion:

Fact: All software sucks. We're here to show you exactly why, and just how much it truly sucks. We don't discriminate against vendor or development model; all software sucks. We are relentless. We show no mercy. If the software exists, we will find its suckage, no matter how much it leverages synergetic business potential. Be prepared.

Hopefully we can reach some software authors and make them see the light. If not, at least I was able significantly reduce my blood pressure through the site.

Here's an interesting article on trying to understand TCP performance. It discusses how the TCP flow-control window (receive buffer), window scaling, selective ACKs and some other TCP features/options affect your link's speed. Of course it's only a tiny fraction of the total picture that is link performance, but it's an interesting read.

There's also a webpage which inspects the TCP options your browser sends and calculates it's maximum theoretical speed.