Consider a system that includes a Web server and two database servers. Both database servers are identical: The first acts as a main server, while the second acts as a redundant backup in case the first one fails. Users use Web browsers to access data through the Web server. They also have the option of using a proprietary client that accesses the databases directly. Draw a UML deployment diagram representing the hardware/software mapping of this system.
What will be an ideal response?
This exercise tests the student’s knowledge of deployment diagrams. Several different solutions exist depending on
the interpretation of the word “server.” Given that the system uses a hot backup redundancy to increase availability,
the student can infer that high availability is a design goal for the system. In this case, the system designers would
also assign each server to a dedicated host, first, to increase the independence of failures, second, to limit damage in
case of failure. Figure 7-1 depicts such a solution with three servers and two clients. An instructor may want to accept
a solution where both database servers and the Web server run on the same host, given that this exercise tests
knowledge about deployment diagrams, not about dependable systems.
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Use the th element to indicate a table column or row _____.
a. data b. heading c. summary d. caption
Match the following file types to their description
I. Sockets A. Unbuffered files used to exchange data II. Character devices B. Virtual connections between two processes III. Named pipes C. Provide a FIFO mechanism IV. Block devices D. Buffered files used to exchange data
____________________ elements are larger elements such as divs, tables, and paragraphs.
Fill in the blank(s) with the appropriate word(s).
Exporting Access data into another program helps to save time and________.
a. increases the difficulty level to the work flow b. deletes files from your hard drive c. reduces the number of errors d. formats data with attractive styles