AWS for Developers For Dummies. Mueller John Paul

rel="nofollow" href="#x7_c02_fig_0001">Figure 2-1 shows examples of services with an expiration date. Notice that you must begin paying for the service 12 months after you begin using it.

       FIGURE 2-1: Some services have an expiration date when you must begin paying for it.

In some cases, the product itself doesn’t have an expiration date, but the service on which it runs does. For example, when viewing the terms for using the free software, the software itself is indeed free. However, to run the software, you must have the required service, which does come with an expiration date (see Figure 2-2). In this case, the Amazon Mobile Analytics depend on Amazon S3 (listed near the bottom of the description). You have access to 100 million events per month free, but in order to export your event data, you need S3, which has an expiration date. Notice also that after you reach the 100 million events level, you must pay an additional amount for each additional million events, so free doesn’t necessarily remain free.

       FIGURE 2-2: Software may be free, but the service on which it runs might not be.

You also have access to some products that are both free and have no expiration date. These nonexpiring offers still have limitations (and often caveats), but you don’t have to worry about using those products within the limits for however long you want (or until Amazon changes the terms). Figure 2-3 shows an example of this kind of service. Notice that the service is free, doesn’t expire, and doesn’t depend on a service that expires. However, you must pay for both throughput and storage, so a cost is still involved.

       FIGURE 2-3: A few services don’t come with expiration dates.

      

Knowing the terms under which you use a service is essential. The free period for services with an expiration date goes all too quickly, and you may suddenly find yourself paying for something that you thought remained free for a longer time frame. Given that Amazon can change the terms of usage at any time, you need to keep checking the terms of service for the services that you use. A service that lacks an expiration date today may have an expiration date tomorrow.

      ABOUT THE GRAPHICS IN THE BOOK

      The material in this book works on several different platforms, including Windows, Linux, and Mac OS X. However, presenting screenshots of every platform you can use with AWS isn’t practical because the book would end up being filled with pictures rather than content. For this reason, the screenshots you see in the book are from a Windows 7 system using the Firefox browser, where appropriate. Depending on the operating system, browser, and other software you use, you may not see precisely the same screenshots on your system. In looking at the graphics, you should compare content rather than precise appearance. Any differences in appearance are normal, and you don’t need to worry about them.

Considering the usage limits

      Look again at Figures 2-1 through 2-3. Note that all these products have some sort of usage limit attached to them – even the free software – because of the software’s reliance on an underlying service. (Some software relies on more than one service, so you must also consider this need.) For example, you can use Amazon Elastic Compute Cloud (EC2) for 750 hours per month as either a Linux or Windows setup. A 31-day month contains 744 hours, so you really don’t have much leeway if you want to use the EC2 service continuously.