Letters
Please congratulate Lydia Kinata for the magazine's new design. I have been waiting a long time for this kind of improvement. Best regards and keep improving.
—Jorge Carminati
I finally had time to read the September issue. The first thing I noticed was the new design. Looks great, keep the change! I've had a subscription for over two years and this, to me, was the best issue (look and content) I've received.
—Matt C.
Robin, I got a copy of the Linux Journal at LinuxWorld and read your article on DreamWorks—what a great visit that must have been!
Given what you saw there and may already know of, I was wondering if you could offer a suggestion. I have a teenage son that is very interested in animation, but the applications to do that are pretty expensive. Can you suggest some Linux-based rendering applications that are more affordable?
—Jack C.
Robin replies: Jack, we had a great time at DreamWorks. But DreamWorks is just the first. All the studios have Linux migration projects underway.
You may want to start with Blender, a popular, freely distributed 3-D modeling package for animation, rendering, interactive 3-D and game creation. Unlike most no-cost animation tools, there are printed books available on Blender. Other tools that may be of interest include K-3D, Ayam, AC3D, Flow, Radiance and BMRT. You can find their web pages by searching at Freshmeat.net
In the September 2001 LJ article “Loadable Kernel Module Exploit”, I was interested in the technique for hijacking the sys_call_table pointer and wrapping it within your own function. I used to do something very similar in DOS in the good ol' days, writing TSRs (Terminate and Stay Resident) and other programs that “borrowed” the bios or dos interrupts vectors.
For programs, it was a simple case of restoring the original interrupt vector (pointer), but with TSRs, one had to be careful before restoring the original pointer. The problem being that if several TSR utilities were installed, two might hijack the same interrupt (often the keyboard). A properly written TSR would, before uninstalling, check that the current pointer pointed indeed to itself, if it didn't, then it could not uninstall as by doing so it would clobber another, later installed, TSR.
The cleanup_module(void) routine in the article performs no such check before restoring the sys_call_table[SYS_write] pointer, something which at first sight appears dangerous to me in a multitasking environment, especially one where the kernel can load and unload modules automatically.
—John Jacq
Realizing the promise of Apache® Hadoop® requires the effective deployment of compute, memory, storage and networking to achieve optimal results. With its flexibility and multitude of options, it is easy to over or under provision the server infrastructure, resulting in poor performance and high TCO. Join us for an in depth, technical discussion with industry experts from leading Hadoop and server companies who will provide insights into the key considerations for designing and deploying an optimal Hadoop cluster.
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Every security policy provides guidance and requirements for ensuring adequate protection of information and data, as well as high-level technical and administrative security requirements for a system in a given environment. Traditionally, providing security for a system focuses on the confidentiality of the information on it. However, protecting the data integrity and system and data availability is just as important. For example, when processing United States intelligence information, there are three attributes that require protection: confidentiality, integrity, and availability.
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| Dynamic DNS—an Object Lesson in Problem Solving | May 21, 2013 |
| Using Salt Stack and Vagrant for Drupal Development | May 20, 2013 |
| Making Linux and Android Get Along (It's Not as Hard as It Sounds) | May 16, 2013 |
| Drupal Is a Framework: Why Everyone Needs to Understand This | May 15, 2013 |
| Home, My Backup Data Center | May 13, 2013 |
| Non-Linux FOSS: Seashore | May 10, 2013 |
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- Drupal Is a Framework: Why Everyone Needs to Understand This
- A Topic for Discussion - Open Source Feature-Richness?
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- Tech Tip: Really Simple HTTP Server with Python
Enter to Win an Adafruit Pi Cobbler Breakout Kit for Raspberry Pi

It's Raspberry Pi month at Linux Journal. Each week in May, Adafruit will be giving away a Pi-related prize to a lucky, randomly drawn LJ reader. Winners will be announced weekly.
Fill out the fields below to enter to win this week's prize-- a Pi Cobbler Breakout Kit for Raspberry Pi.
Congratulations to our winners so far:
- 5-8-13, Pi Starter Pack: Jack Davis
- 5-15-13, Pi Model B 512MB RAM: Patrick Dunn
- 5-21-13, Prototyping Pi Plate Kit: Philip Kirby
- Next winner announced on 5-27-13!
Free Webinar: Hadoop
How to Build an Optimal Hadoop Cluster to Store and Maintain Unlimited Amounts of Data Using Microservers
Realizing the promise of Apache® Hadoop® requires the effective deployment of compute, memory, storage and networking to achieve optimal results. With its flexibility and multitude of options, it is easy to over or under provision the server infrastructure, resulting in poor performance and high TCO. Join us for an in depth, technical discussion with industry experts from leading Hadoop and server companies who will provide insights into the key considerations for designing and deploying an optimal Hadoop cluster.
Some of key questions to be discussed are:
- What is the “typical” Hadoop cluster and what should be installed on the different machine types?
- Why should you consider the typical workload patterns when making your hardware decisions?
- Are all microservers created equal for Hadoop deployments?
- How do I plan for expansion if I require more compute, memory, storage or networking?




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