CS401 S99 Midterm Review

by Edward Chow

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There will be 4 questions asked.  Your grade will be based on the best three answers.
There will be a link from here to the midterm web page.  Here is the link to midterm. It will be turn on 12:15pm, 3/16.  You will have 1 hour 15 min. to work on the midterm.   You can work at home or at PC lab where you can access it through a web browser.  Since some of the questions will be related to Apache server configuration directives, you need to be able to access server document web pages (at www.apache.org or at bilbo.uccs.edu).  Here are questions related to the four areas we covered:

1. Basic Apache Web Server Configuration and Operation.
• Why is it not wise to run the web server as root?
• How does Apache  adjust to the requests?
• How is a uri in the http request commnad line mapped to the full path name of the corresponding web document in server's file system?
• How and why are cgi scripts treated differently in Apache web server (compared with normal static web pages)?
• How cookie can be used to track a user's Internet access (or on-line purchase) pattern?
• How to set up the server to intercept files with special extension, perform additional operations on the documents, and then return them to the clients?
2. Virtual Hosting (IP-based vs. Name-based).
• What is involved in setting up IP-based virtual hosting?
• What is involved in setting up a name-based virtual hosting?
• What is the trade-off between using IP-based virtual hosting and using Name-based virtual hosting?
3. Authentication.
• How does the server detect that the directory or location is protected and required authentication?
• How does the server inform the client that the requested url is required authentication?  What hint is provided by the server?
• How does the client respond to the authentication request?
• What encoding method is used for the login and password pairs?
• What is the difference between using AuthUserFile and using AuthDBMUserFile?
4. Proxy/cache server and web load balancing.
• Why can the cache server reduce the Internet traffic of an organization?
• What is the drawback of using a cache server?
• Why are the cached documents  saved with a MD5 hashed file name?
• Why are the cached documents spread in directories with the multi-level hierarchy?
• What are the three basic factors that impact on the web system performance?
• Which metric is used by most web server benchmarks? What is it meant?
• How proxy/cache server can be used in balancing the load of geographically separated web servers and clients?  What part of the proxy/cache needs to be modified or enhanced? How the apache status module can be used in a web load balancing system?