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.
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.
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?
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.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
- Paranoid Penguin - Building a Secure Squid Web Proxy, Part IV
- SUSE LLC's SUSE Manager
- Google's SwiftShader Released
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Managing Linux Using Puppet
- My +1 Sword of Productivity
- Non-Linux FOSS: Caffeine!
- SuperTuxKart 0.9.2 Released
- Parsing an RSS News Feed with a Bash Script
- Rogue Wave Software's Zend Server
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide