Mobile Computing with Linux
Power management is not really supported under Linux. Based on the Linux Laptop Survey results, a laptop running Linux will typically last for two hours on batteries. Although an APM support package does exist, it only provides the initial hooks into the APM BIOS for power management. At this point the APM support just recognizes when the system returns from sleep mode and updates the internal clock, which is important to keep the system sane. APM applications that display the current battery level and execute the “shutdown” command when the battery runs low are also available. This software may be retrieved from tsx-11:/pub/linux/ packages/laptops/apm.
As mentioned earlier, the SL processor series has SMM features to power manage the processor. However, a portable power management solution that doesn't require SMM support is to halt the processor in the scheduler's idle loop. The x86 asm(hlt) instruction suspends the processor until there is an interrupt from the system (e.g. a key stroke). Linux versions above v1.1.10 implement this simple and effective solution, which does not degrade performance at all. It has the added benefit (even to non-laptop users) of increasing the expected life of your CPU.
PCMCIA provides plug-and-play capabilities to the laptop. Currently support exists for the Intel 82365 adaptor chip, PCMCIA modems (Megahertz, IBM, Intel, AT&T, and others), and ethernet cards (D-Link 650, Linksys, IBM credit card, and 3COM 3c589). The PCMCIA support in Linux is still in its alpha stages and is available from tsx-11:/pub/linux/packages/laptops/pcmcia. PCMCIA support that meets the PCMCIA Unix specification is in the works and you may expect it to be part of the standard Linux distribution by the end of the year.
F. Douglis and B. Marsh, Low-Power Disk Management for Mobile Computers, Matsushita Information Technology Lab, 2 Research Way, Third Floor, Princeton, NJ, 1993, MITL-TR-53-93
Fred Douglis and P. Krishnan and Brian Marsh, Thwarting the Power-Hungry Disk, Proceedings of the 1994 Winter USENIX Conference, January 1994, (Also Matsushita Information Technology Lab Technical Report MITL-TR-61-93)
Proceedings of the 1994 Winter USENIX Conference, January 1994
Marc E. Fiuczynski (email@example.com) is a computer science graduate student at the University of Washington in Seattle. His research interests are distributed systems, communications, operating systems, and mobile computing.
Practical Task Scheduling Deployment
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.
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- The Firebird Project's Firebird Relational Database
- Stunnel Security for Oracle
- My +1 Sword of Productivity
- Non-Linux FOSS: Caffeine!
- Managing Linux Using Puppet
- SUSE LLC's SUSE Manager
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Doing for User Space What We Did for Kernel Space
- SuperTuxKart 0.9.2 Released
- Google's SwiftShader Released
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