15-441 Assignments

There will be two programming projects and four written homework assignments.

All homework is to be done individually. The programming projects will be done in groups of two students.

The projects are done in groups for two reasons. The first is the size of the class. The second and more important reason is that this is an opportunity to experience the joys and frustrations of working with others. It's a skill you only get better at with practice.

Since 15-441 fulfills the project-class requirement of the CS degree, you will be expected to learn and practice good software engineering, as well as demonstrate mastery of the networking concepts. Both partners in a project group will need to fully understand the project and your solution in order to do well on those exam questions relating to the projects. For example, a typical question might be: "When you implemented X, you came across a particular situation Y that required some care. Explain why this simple solution Z doesn't work and describe how you solved it." We'll pick questions such that it will take some effort to figure out Y. If you didn't take the time to work the problem yourself and just relied on your partner, you won't have enough time during the test to figure it out. Be careful, the insights you'll need will come only from actually solving the problem as opposed to just seeing the solution.

By their nature, the assignments aren't going to be completely comprehensive of everything you'll encounter in the real world or in class. To assist you, we've compiled a list of suggested study problems that you may want to do in addition to the normal homework. They're not graded, but they'd make great topics to discuss with the course staff during office hours.

Notes on the 15-441 Programming Projects

A key objective of 15-441 is to provide a significant experience with system programming, where you must write programs that are robust and that must integrate with a large, installed software base. Oftentimes, these programs are the ones that other people will build upon or use as tools. Systems programming is very different from the application program development you have done in earlier courses:

• It is typically done in a low-level language, such as C, to ensure close control over system resources.
• Especially with server code, it must be designed to run indefinitely. It must handle reliably handle every possible error condition, and it must manage resources such as memory with care.
• It must be secure. Connecting a system to a network makes it vulnerable to malicious attacks initiated anywhere in the world. Poorly designed or implemented network software provides a common entrypoint for attack. System software must be invulnerable to flaws such as string overflows or malformed incoming messages. (This point bears repeating: Any system software must stringently check input it receives from the network or from the user. Do not trust either one! They're often out to get you.)
• The interfaces to other parts of the system are generally specified by documented protocols.
• Networking software typically involves concurrency, both within individual machines (multiple processes or threads) as well as among the different network components.
• An important part of system programming is to develop comprehensive test methods for the programs. A significant effort should be invested in writing programs that will thoroughly test the system code, including the handling of different error conditions.

We'll go into more detail about each of these points during the recitation sections. But keep in mind: The programming assignments in 15-441 are larger and more open-ended than in other courses. Doing a good job on the project requires more than just producing code that runs: it should have a good overall organization, be well implemented and documented, and be thoroughly tested.

Last updated: Thu Dec 14 20:01:19 EST 2006 [validate xhtml]