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17. Virtual and Ambient Places

Andrew Hinton O'Reilly Media ePub

It’s funny how the colors of the real world only seem really real when you viddy them on the screen.

ALEX, IN A CLOCKWORK ORANGE, ANTHONY BURGESS

SEMANTIC INFORMATION CAN BE TRULY IMMERSIVE. Whether it’s an all-night dorm conversation or losing yourself in an engrossing novel, language can swallow our attention whole. When you add more layers to the semantic environment, meaningful experiences of place can emerge. Take a role-playing game such as Dungeons & Dragons (Figure 17-1). For the players, the physical surroundings—a friend’s kitchen table or the back of a hobby shop—recede into mist as the shared story of the campaign becomes more palpable and compelling. Even as a teenager, when I was an active player, I marveled at how all it took was some scribbling on paper, some rules, and some dice to create a fully engaging environment that my friends and I could inhabit until dawn.

Digital technology is turning the sorts of rules and maps we find in a tabletop game into actively inhabited virtual places as well as radically transformed physical ones. We find one example in text-based Multi-User Dungeons (or Domains), more commonly known by their acronym “MUDs” (and variants MUSH, MOO, and so on). Invented almost as soon as computers with command-line interfaces could be networked, MUDs establish immersive environments in which players can interact as they find treasure and slay monsters, or in some cases just socialize and build new places and objects.

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Medium 9781449309459

6. Copying, Renaming, and Moving Entries

Eric Bidelman O'Reilly Media ePub

FileEntry and DirectoryEntry share common API calls for common tasks such as copying, renaming, and moving an entry. This chapter covers these operations in a generic way, but the concepts can be applied to either entry type.

Copying a file or folder to a different location on the filesystem is possible with copyTo(). By design, copying a folder is recursive, while files are simply duplicated:

The first parameter is a DirectoryEntry, the parent folder to move the entry into. The second argument is an optional new name to give the copied entry. The third and fourth parameters are our usual suspects, a success and error callback.

Attempting to copy an entry in an illegal way can result in an error. Two common errors are trying to copy an entry inside itself and trying to copy an entry in the same folder without specifying a new name.

As an example usage, the following snippet copies the file me.png from one directory to another.

Example6-1.Copying a file to a different folder

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Network Connections

Daniel J. Barrett O'Reilly Media ePub

ssh stdin stdout - file -- opt --help --version

The ssh (Secure Shell) program securely logs you into a remote machine where you already have an account:

Alternatively, it can invoke a program on that remote machine without logging you in:

ssh encrypts all data that travels across its connection, including your username and password (which youll need to access the remote machine). The SSH protocol also supports other ways to authenticate, such as public keys and host IDs. See man sshd for details.

-l user

Specify your remote username; otherwise, ssh assumes your local username. You can also use the syntax username@host:

-p port

Use a port number other than the default (22).

-t

Allocate a tty on the remote system; useful when trying to run a remote command with an interactive user interface, such as a text editor.

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How to Choose the Right TV Receiver(s)

Campbell, Tony O'Reilly Media PDF

Figure 6. Click on the Start FM button to begin listening to FM broadcasts.

When the FM tuner locates a radio station and registers a strong signal, MCE will stop seeking and play the channel. You now have the option to use the Tune buttons (the + and – signs) to fine-tune the frequency or manually select another frequency, if desired.

If you want to add a particular radio channel to your station-preset list, click the

Save button and add the channel to one of the nine available preset slots shown on the screen.

Tip

It’s possible that you will hear static when you start the FM tuner, especially with a newly installed card. This happens if the frequency the tuner starts on is not a discernable radio broadcast. To start the tuner without static, you must first create and select a channel preset before clicking the Start FM button.

How to Choose the Right TV Receiver(s)

The TV tuner (or tuners) you select to install in your Media Center PC will provide you with the television experience you require from MCE. For example, if you want to receive traditional analog television broadcasts, you will need to have

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10. The Cloud

Burt Beckwith O'Reilly Media ePub

“The cloud” is a buzz topic right now, and for good reason. Cloud computing isn’t the best approach for every deployment, but for many scenarios, using a cloud provider can save time and money, and make your applications less susceptible to traffic surges. It can also greatly simplify your deployment process and IT needs.

There is no one definition of cloud computing, and it is starting to become a misused term (some are now referring to any online service as a cloud service). In fact, there are three models of cloud computing: infrastructure as a service (IaaS), software as a Service (SaaS), and platform as a service (PaaS). They’re all cloud services though—meaning, they’re available over the Internet as metered (“pay as you go”) services. SaaS examples include popular consumer services like Gmail, Hotmail, Facebook, and YouTube and also more specialized software services available in a metered fashion over the Internet. Amazon EC2, VMware vCloud, and Linode are popular IaaS options, and Amazon Elastic BeanStalk, Heroku, Cloud Foundry, and Cloudbees are popular PaaS options. Although Grails developers may integrate or create SaaS solutions, we will focus on IaaS and PaaS, because they are more integral to the development and deployment process. Also note that although Google App Engine is a viable option for traditional Java applications, Grails applications typically don’t do well there; consider using Gaelyk instead to take advantage of a Groovy-based Grails-like environment.

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