H Petroski The Evolution of Useful Things How Everyday Artifacts From Forks and

H petroski the evolution of useful things how

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H. Petroski. The Evolution of Useful Things: How Everyday Artifacts-From Forks and Pins to Paper Clips and Zippers-Came to be as They are . Vintage, 1994. ISBN 0679740392. P. van Hardenberg. Personal communication, April 2012. 12.14 Suggested Projects For many of these exercises, you will find it useful to create a rake task that creates a specified large number of randomly-generated instances of a given model type. You will also want to deploy a ’staging’ copy of your app on Heroku so that you can use the staging database for experiments without modifying the production database. SaaS Performance and Scaling: Project 12.1. Seed the staging database with 500 movies (randomly generated is fine) to RottenPotatoes. Profile its deployed performance on Heroku using New Relic. Add fragment caching around the movie partial used by the index view and re-profile the app. How much improvement in responsiveness do you observe for the index view once the cache is warmed up?
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Project 12.2. Continuing the previous exercise, use httperf to compare the throughput of a single copy of your app on the index action with and without fragment caching. (On Heroku, by default any apps on a free account receive 1 “dyno” or one unit of task parallelism, so requests are performed sequentially.) Project 12.3. Use external monitoring to analyze a software design from the perspective of a significant external quality attribute such as functionality, performance, or availability. Note: The margin icon identifies projects from the ACM/IEEE 2013 Software Engineering standard ( ACM IEEE- Computer Society Joint Task Force 2013 ). Project 12.4. Continuing the previous exercise, add action caching for the index view so that if no sorting or filtering options are specified, the index action just returns all movies. Compare the latency and throughput with and without action caching. Summarize the results from all three exercises in a table. Releases and feature flags: Project 12.5. Investigate the availability cost of doing an “atomic” schema update and migration as described in Section 12.4 . To do this, repeat the following sequence of steps for N = 2 10 ,2 12 ,2 14 : 1. Seed the staging database with N randomly-generated movies with random ratings. 2. Run a migration on the staging database that changes the rating column in the movies table from a string to an integer (1=G, 2=PG, and so on). 3. Note the time reported by rake db:migrate . Suppose your uptime target was 99.9% over any 30-day window. Quantify the effect on availability of doing the above migration without bringing your service down. Project 12.6. Outline the process of regression testing and its role in release management.
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Reliability: Project 12.7. List approaches to minimizing faults that can be applied at each stage of a Plan- and-Document lifecycle. Project 12.8. In Section 5.2 we integrated third-party authentication into RottenPotatoes by adding an authentication provider name and a provider-specific UID to the Moviegoer model.
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