Performers Go Web
Writers, musicians, painters, filmmakers and artists of every kind are using the Web as a platform. Only one traditional art form does not have a strong presence in cyberspace yet—theater. But, as soon as one is willing to adapt to the medium, a new art form evolves, cyberformance.
The term cyberformance was coined by New Zealand performance artist Helen Varley Jamieson to describe “performance that uses the Internet to bring remote performers together, in real time, in a live theatrical event”. She has been working for several years with the cyberformance troupe Avatar Body Collision, using free Internet chat applications to create performances in cyberspace. To provide her, her coperformers and their audience with a Web-based stage, she initiated an open-source project called UpStage, written by Douglas Bagnall (see the on-line Resources). The first release, launched in January 2004, was funded by the New Zealand Ministry of Research, Science and Technology and Creative New Zealand, and funds now are being sought to continue its development.
Of course, the software isn't restricted to on-line performances. UpStage also makes an interesting tool for on-line teaching, as well as product and other types of presentations. It even serves as a collaboration tool for virtual workgroups. UpStage's strength is its user-friendly and highly accessible interface: players and audience alike need to have nothing more than a standard browser and Internet connection to participate. Newbies can learn the basics and find themselves happily text-rapping and avatar-hopping in no time.
The server software itself is written in Python and comes with its own Web server, giving artists the opportunity to set up a stage easily, wherever their laptop is located on-line. Apart from the Web server, which requires the Python Twisted framework, the software makes extensive use of other open-source programs commonly installed on Linux systems, such as the text-to-speech-system Festival, the netpbm tools and gif2png. See the Problems with GIFs sidebar to this article for more details.
Often not shipped with Linux distributions are swfttools and the MP3 encoder lame. The timeout program from The Coroner's Toolkit, which is used during speech synthesis, also generally is not included. But it usually can be omitted if one isn't afraid to touch the source code.
The stage is a Flash client, and here is where the swfttools enter the picture. They convert the PNGs and JPEGs used both for stage decoration and as avatars into Flash format. Hence, performers and audience alike need the Macromedia Flash plugin for their Web browsers. KHTML- and Mozilla-based browsers work fine, but at present, Opera isn't suitable.
Unfortunately, at the time of this writing, the current version of UpStage does not honor PATH settings. Therefore, it is wise to check whether all the above-mentioned programs are situated in one of the directories that are hard-compiled into /bin/sh:
$ strings /bin/sh | grep -E "/(bin|sbin)" [...] /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin: /sbin:/bin
If not, appropriate links should be set. Otherwise, error hunting can become tricky, as UpStage isn't good at providing meaningful error messages in every situation. Things become even more complicated when using the sound tools. Despite UpStage using graphics tools in /usr/local/bin, it doesn't necessarily find lame there. So for users who aren't up to hacking the source, creating a link named /usr/bin/lame seems unavoidable.
Now it is time to start the server. Unpack the source archive, Upstage-2004-09-28.tar.gz, and enter the newly created Upstage directory. Here, you find the shell script go.sh that tries to kill an old twisted-server mentioned in the file Upstage/twistd.pid and starts a new one. So, don't worry about the relevant error message when you run ./go.sh as a nonprivileged user for the first time. It's only then that Upstage creates the pid-file.
For security reasons, it is not advisable to run UpStage as root. That's why the server uses an unprivileged port above 1024. The port on which your UpStage server runs can be configured. If you dislike the default port 8081, change the line:
WEB_PORT = 8081
in Upstage/upstage/config.py, and re-run ./go.sh.
Because the September 2004 version of UpStage is missing the directory that the server uses to store temporary MP3 files, you can save yourself a lot of trouble if you create it by hand:
Now, point your local Web browser to the following: http://localhost:8081/, and you should end up at the entrance to your theater (Figure 1). To customize it according to your needs, change its HTML code in Upstage/html/index.html and the corresponding stylesheet, Upstage/html/style/main.css. It's a good idea to keep the relative link "<a href="/stages"></a>" to the stages—your audience will be grateful—and the login for the artists.
The theater also has a back door for its personnel. The URLs http://localhost:8081/admin and http://localhost:8081/login.html lead you directly to a login dialog that can be changed in Upstage/html/login.html.
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.
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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