The Collaborative Virtual Workspace
You walk down the hallway and go into the design room. It's as hectic here as always; stuff is lying all over the floor. Alex, the lead architect, is here with two other designers, Brad and Lynn. They have been discussing the architecture for the new project.
“I think we've almost got it,” says Alex, “take a look at our design.” He hands you a document, which you duly examine.
“Not too bad,” you reply, “but you might want to look at something.” You walk over to the whiteboard and draw out a rough sketch. Brad sees where you're heading, grabs a marker, and adds some components to your drawing.
Lynn notices a problem and says “We may have some problems implementing the security interface with that. Let me give Rachel in security a call.” She grabs the phone, and after a quick conversation, tells everyone the impact the security team sees from this implementation.
“Okay,” you say, “sounds like you guys are on the right track. I'll carry this preliminary design over to the programmers and get a rough estimate on the time they'll need to implement it.” As you walk out, you notice your beeper has a message from your secretary reminding you of a meeting at 3:00 with the division head.
Activities like these occur in work environments every day; however, in this scenario the individuals involved never physically moved. In fact, one person sits down the hall from you, another works at a remote site, and the third was at home. Yet everyone was able to interact as though individuals, objects and documents were physically colocated.
As computers move to take a dominant position in the workplace and at home, the interactions between people change significantly. Instead of gathering around a water cooler or at a small cafe, meetings have moved to the Internet. However, with this change of venue come certain restrictions. No longer can you read a person's body language or infer meanings from the tone of someone's voice. With many Internet collaboration tools, such as Internet Relay Chat (IRC) or instant messengers, you can only interpret the words others type.
The project on which I currently work, the Collaborative Virtual Workspace (CVW), looks to add more meaning to computer-based social interactions. Instead of relying solely on spoken words, CVW adds actions, audio and video, and a more descriptive virtual environment to social settings. Additionally, users within the CVW environment can create and pass around various artifacts, such as documents and pictures. This is because CVW implements a persistent storage mechanism in conjunction with the environment. Anything created within CVW can be saved for others to see whenever they like.
Best of all, CVW is freely available. To further encourage innovation in collaborative systems, The MITRE Corporation has made CVW an open source software product. By disseminating CVW in this manner, different communities can begin to experiment with and understand synchronous computer-based collaboration. We believe collaboration systems such as CVW will continue to evolve, and the Internet community will have much to offer.
Let's look at where CVW comes from and what makes up our virtual environment.
From it's inception in 1994, CVW was built on a client-server architecture. At the heart of the server is a MUD, Object-Oriented (MOO) from Xerox PARC (ftp://ftp.lambda.moo.mud.org/pub/MOO/). Once only within the domain of dungeons and dragons players, MUDs and MOOs have progressed to incorporate numerous social settings. Although providing a very descriptive environment, MOOs present one challenge to the average computer user today—they are predominantly text driven. With no fancy graphic interfaces or elaborate designs, a user simply connects to a server using a MOO client program or telnet, logs in and begins interacting within the environment.
One of the true strengths of a MOO server is its extensibility. The server contains an object-oriented programming language called “MOO”. Using the MOO language, programmers can create new rooms, implement new actions, and provide various means of interacting with others within the virtual environment. Add the ability to allow a large number of people to connect simultaneously, and it's easy to see why MOOs have become a popular collaboration environment.
If you download the LambdaMOO source code and run it on your Linux box, you'll notice not much exists in that environment by default. Each MOO administrator must either build a new virtual environment, or obtain the code someone else has written.
CVW's MOO server already contains the code for our virtual environment. We have extended our MOO server in order to create a large building, the floor plan of which displays graphically in the client. Although this tightly couples the client to a CVW server exclusively, it does provide a more intuitive interface for new users. The building consists of several floors, each with seven rooms and various other meeting places (hallway, lobby). These can be modified to suit any group's needs.
Using a room-based metaphor provides two other distinct advantages. First, session management can be logically partitioned. Each room will administer the particular session requirements for the users in that area. By having this controlled at the server side, any clients connecting to the server do not have to configure their audio, video or document settings to communicate with the other users. Secondly, security can likewise be easily controlled. As each room may implement an individual access control policy, private meeting places can be created. Again, this provides a very intuitive means of implementing security—if the server denies a user access to a room, they usually understand they don't have permission to enter that area.
In addition to the MOO server, we incorporated document persistence into our collaboration system. This allows CVW to encompass the role of a collaboration framework. If individuals meet to discuss a topic, they may create documents or graphics using whatever tools that may be available to them (document editors, drawing programs). Using CVW, users can import these external documents and allow others to view or edit them. Although MOOs do allow users to create objects, these are normally simple text documents that can't be easily exported to other external applications. This persistence capability allows for asynchronous collaboration—users may enter or leave the room whenever they desire, but they would still have access to the work being performed.
Since the addition of persistence incorporated a significant change to a MOO environment, we implemented this functionality as a unique server process, the Document server. This server does not have to run on the same machine as the MOO server, but it should have enough disk space available to store all the documents created by the users. Storage of documents is quite simple—basically, a flat database directory. To date this has proven sufficient, but a large implementation of CVW may want to look to re-engineer this process.
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.
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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