Fine software projects, news and thoughts from the Linux world.

How to check when Daylight Saving Time (DST) will commence?

Using time zone dumper utility (zdump) like this:

zdump -v /etc/localtime | grep 2007

we can see that:

/etc/localtime Sun Mar 25 00:59:59 2007 UTC = Sun Mar 25 01:59:59 2007 CET isdst=0 gmtoff=3600
/etc/localtime Sun Mar 25 01:00:00 2007 UTC = Sun Mar 25 03:00:00 2007 CEST isdst=1 gmtoff=7200
/etc/localtime Sun Oct 28 00:59:59 2007 UTC = Sun Oct 28 02:59:59 2007 CEST isdst=1 gmtoff=7200
/etc/localtime Sun Oct 28 01:00:00 2007 UTC = Sun Oct 28 02:00:00 2007 CET isdst=0 gmtoff=3600

How to extract contents of an RPM package

Use the following procedure to extract contents of an RPM package:

rpm2cpio package.rpm | cpio -dimv

As the name implies, rpm2cpio takes an RPM package file and converts it to a cpio archive. The -i flag to the cpio command indicates that cpio is reading in the archive to extract files, and the -d flag tells cpio to construct directories as necessary. The -v flag tells cpio to list file names as files are extracted, and the -m flag tells cpio to retain previous file modification times when creating files.

Asterisk: The Future of Telephony

The result of hundreds of hours of painstaking labor, this book represents the work of Jim Van Meggelen, Jared Smith, and Leif Madsen over the past year. Thanks to O'Reilly Media for publishing the book and agreeing to publish it under the Creative Commons license.

Book description

It may be a while before Internet telephony with VoIP (Voice over Internet Protocol) reaches critical mass, but there's already tremendous movement in that direction. A lot of organizations are not only attracted to VoIP's promise of cost savings, but its ability to move data, images, and voice traffic over the same connection. Think of it: a single Internet phone call can take information sharing to a whole new level.

How fast is your disk?

With a little bit of torturing, and some fun on the way, find out how fast your hard disk drive really is.


1-Terabyte hard disk drives are slowly coming to the market, so I suppose we can't complain that we don't have enough space to save (the ever increasing amount of) our precious data. But, it's also a known fact that although disk storage capacities are improving at an impressive rate, disk performance improvements are occurring at a rather slower rate. Unfortunately, larger disk doesn't always mean faster disk. What follows is an explanation of two techniques for measuring disk performance in Linux.

Linux Kernel in a Nutshell

Written by a leading developer and maintainer of the Linux kernel, Greg Kroah-Hartman, Linux Kernel in a Nutshell is a comprehensive overview of kernel configuration and building, a critical task for Linux users and administrators.

No distribution can provide a Linux kernel that meets all users' needs. Computers big and small have special requirements that require reconfiguring and rebuilding the kernel. Whether you are trying to get sound, wireless support, and power management working on a laptop or incorporating enterprise features such as logical volume management on a large server, you can benefit from the insights in this book.

Humble Little Ruby Book

By Jeremy McAnally
Available in print ($10)

What is Ruby anyhow?

Ruby is an open-source, multi-paradigm, interpreted programming language (a bit of a mouthful I know! I'm going to explain it, I promise!). Ruby was created by Yukihiro "Matz" Matsumoto, a very fine Japanese gentleman who currently resides in Shimane Prefecture, Japan; Matz's work on the language was started on February 24, 1993 (commonly considered the birthday of the language; I hear that over in Japan they roll out a two-story cake and sing) and released to the public in 1995. Ruby is often hailed as one the most expressive and concise languages available to developers today. In that spirit of expressiveness, let's look at exactly what it all means. Let us now eviscerate these verbal furbelows with conviction!

Finally user-friendly virtualization for Linux

The upcoming 2.6.20 Linux kernel is bringing a nice virtualization framework for all virtualization fans out there. It's called KVM, short for Kernel-based Virtual Machine. Not only is it user-friendly, but also of high performance and very stable, even though it's not yet officialy released. This article tries to explain how it all works, in theory and practice, together with some simple benchmarks.

A little bit of theory

There are several approaches to virtualization, today. One of them is a so called paravirtualization, where the guest OS must be slightly modified in order to run virtualized. The other method is called "full virtualization", where the guest OS can run as it is, unmodified. It has been said that full virtualization trades performance for compatibility, because it's harder to accomplish good performance without guest OS assisting in the process of virtualization. On the other hand, recent processor developments tend to narrow that gap. Both Intel (VT) and AMD (AMD-V) latest processors have hardware support for virtualization, tending to make paravirtualization not necessary. This is exactly what KVM is all about, by adding virtualization capabilities to a standard Linux kernel, we can enjoy all the fine-tuning work that has gone (and is going) into the kernel, and bring that benefit into a virtualized environment.

The difference between Xen & VMware

Virtualization is a hot topic these days. With hardware getting more and more capable, by means of cheap multi-core processors and gobs of memory, we can expect virtualization to become only more important in the coming years. Virtualization promises reduced costs for IT organizations, both hard (machines, power, cooling) and soft (admin and operations personnel).

First benchmarks of the ext4 file system

Seeing that the development of the ext3 file system successor has started, and that Andrew Morton has released mm patch containing ext4 file system, I decided to run some simple benchmarks, even in this early stage of development.

Because the mm patch also contains Hans Reiser's reiser4 file system, I decided to run benchmarks against it, too, for a good measure. Let me once again remind that both ext4 and reiser4 are still in development, while ext3 has been in production for many years, so take all the results below with a grain of salt.

Ubuntu vs Debian: this is amazing!

The other day I was playing with fun Google Trends tool and got an idea to check Ubuntu versus Debian popularity. You can see the result on the picture below and I don't know about you, but it simply amazes me how popular Ubuntu is these days. And not only that, but its popularity is growing day by day, while it can be easily seen that Debian is either stagnating or slowly fading out.

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