One Minute Evaluations for 24-26 February

CS 537 - Client-Server Interfaces

• Topic: Concurrent, process vs. threads; synchronization.

• Question: If recv is blocking, what should I use to receive the messages, making sure I am not blocking, reading full even for slower clients?

  One minute response: You should either use a non-blocking read, or use select-like mechanisms to pick only those sockets that are ready to be read.

• Topic: Threads, architecture, thread-based concurrency; Zombie and how to handle it.

• Topic: Discussion of Project 1; process concurrency, os support, mechanisms; thread based concurrency; processes vs. threads; advantages and disadvantages of threads; IO support, thread support, architectures, FLASH vs. SEDA.

• Topic: Process concurrency; thread concurrency.

• Topic: Threads, support, advantages, disadvantages.

• Topic: Process-based servers; concurrency and managing threads.

  Question: What is Denial of Service Attacks (DOS)?

  One minute response: A DOS is an attempt to force a program to do so much work that it can't keep up with the load and (effectively) stops working. The traditional way to implement a DOS attack is to flood the system with fake requests.

• Topic: Process concurrency; thread concurrency.

  Question: Why we use SIGCHLD signaling? What is zombie area?

  One minute response: You use it because you have to, on most Unixen; if you ignore SIGCHLD, you'll have zombie problems. I'm not sure; unhandled zombies migrate up to the init process, where they are recognized and disappear.

• Topic: Process-based vs. thread-based concurrency.

• Topic: Process and thread concurrency.

  Question: In Java, how are threads implemented? Library and scheduler to control them? Or are they actually mapping to system equivalent threads? Or is it the combination of both?

  One minute response: See the answer in last week's One Minute Review.

• Topic: Process concurrency; thread-based concurrency, advantages and disadvantages; thread architectures.

This page last modified on 16 July 2003.