Having Fun on ViewSurf
Beach Report and Snow Report are free services for the end user, but Nicolas created ViewSurf in the hope of making some money with it. He's currently trying to sell the service to French Tourism Offices, but it's quite hard; basically, France is lagging in communications and Internet services. Additionally, many French people consider computers and the Internet as American Trojan horses such as McDonald's or Disneyland Paris.
Most French on-line services are available for a low performance Videotex-compatible terminal called Minitel, which was distributed free of charge by France Telecom at the beginning of the 1980s. This technology is obsolete, but France Telecom is currently the only French operator for communications. The Minitel allows them to charge up to several dollars per minute for some on-line services. This could be the reason why most French people don't have a PC at home, and as a result, Internet-based services are not seriously considered.
Nicolas has gotten a contract with the government organization which deals with traffic regulation in Paris. Some French highways have been on the Net since September 1997. If you compare it with other WebCAM systems, ViewSurf gives very good quality for a small data size.
This software would be more easily configurable without editing crontab or shell scripts each time you wished to change the call time or add a new site. To that end, I wrote a set of CGI (Common Gateway Interface) scripts which present a simple and portable interface for the Linux server configuration. The advantage of using CGI instead of standard Linux programs is the capability to configure the server from any forms-capable browser running on any operating system.
Another crucial option is to have the ability for several users to look at a “live” video (not recorded files) at the same time. For this, the Linux PC could be used as a server to distribute the live image from ViewCOM to several users connected from the Net. To reach this goal, I wrote a multi-threaded Linux daemon, based on the POSIX 1003.1c LinuxThreads library by Xavier Leroy (http://pauillac.inria.fr/~xleroy/linuxthreads). Actually, this daemon handles only the “video/x-vcr” MIME type and uses two specific TCP ports. The live video can be inserted in an HTML page with a line such as:
<EMBED SRC="http://your_linux_server:daemon_port" WIDTH=320 HEIGHT=240>
The second port is reserved for ViewCOM administration, such as setting brightness or contrast. Additionally, the daemon can control a weather station in order to get real-time information about external temperature, wind speed and other weather information. A VISCA (a standard for video camera remote control) functionality is about to be added to control zoom, pan-and-tilt and other camera parameters directly from the Internet browser. Figure 4 is a snapshot of the Bordeaux/Bayonne motorway on the private COM1 web server.
The ViewCOM is often connected to the PC via a serial line, but one of the most important advantages of the system could be the ability to control a remote ViewCOM. So, it's not necessary to install a PC on the site you want to look at, you just have to set up a ViewCOM connected to a simple phone line or a leased line. In the phone line case, it's possible for the daemon to call the ViewCOM at starting time or only when an HTTP request occurs. In this last case, the daemon hangs up the line when the last client is disconnected.
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||Jul 29, 2016|
|Stunnel Security for Oracle||Jul 28, 2016|
|SUSE LLC's SUSE Manager||Jul 21, 2016|
|My +1 Sword of Productivity||Jul 20, 2016|
|Non-Linux FOSS: Caffeine!||Jul 19, 2016|
|Murat Yener and Onur Dundar's Expert Android Studio (Wrox)||Jul 18, 2016|
- The Firebird Project's Firebird Relational Database
- Stunnel Security for Oracle
- My +1 Sword of Productivity
- SUSE LLC's SUSE Manager
- Non-Linux FOSS: Caffeine!
- Managing Linux Using Puppet
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Parsing an RSS News Feed with a Bash Script
- Google's SwiftShader Released
- Doing for User Space What We Did for Kernel Space
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