Howdy Class -- Here is the second homework assignment. If you are taking the class for elective credit in the CS Major, do all the problems -- Parts I and II. If you are taking the class for credit, but not as an elective in the CS Major, just do the first set of problems -- the ones for the Nemeth book -- Part I. The problems are due midnight Friday, March 28. I prefer that you just fill out the answers in a copy of this e-mail and send it to me by e-mail. Many of these problems can be answered well with just a sentence or two. Some require a bit of thought, and some extra wording. Use good judgement. That's a part of what I will be grading you on. Answers that offer inadequate information and/or aid to understanding will receive little credit, even if technically correct. Remember that the point of these exercises is for you to demonstrate that you have read and understood the material. Therefore always give the "textbook" answer (Nemeth or Daemon, as the case may be) along with any individual opinions or answers that you want to put forward. -- john ////////////////////////////////////////////////// PART I: Homework #2 Problems for Nemeth Chapter 21: Electronic Mail Chapter 12: Syslog and Log Files Chapter 02: Booting and Shutting Down ////////////////////////////////////////////////// ///////////////////////////////////////////////////// Questions on Chapter 21 of Nemeth -- Electronic Mail ///////////////////////////////////////////////////// ----------------------------------------------------------------- Besides a person, what can e-mail be delivered to? ----------------------------------------------------------------- What sort of problems come with NFS-exporting the mail spool directory to all hosts in order to "centralize" mail? ----------------------------------------------------------------- If you are logged into host1 and you want to send mail to a user with login name joe on host1, and you want to make sure that the mail is *not* redirected due to effects of /etc/aliases or ~joe/.forward, how should you address the message? ----------------------------------------------------------------- What is the purpose of the -q option of sendmail? ----------------------------------------------------------------- //////////////////////////////////////////////////////////// Questions on Chapter 12 of Nemeth -- Syslog and Log Files //////////////////////////////////////////////////////////// ----------------------------------------------------------------- Why do you sometimes have to send a signal to a daemon when you rotate log files? Explain what could happen if you don't send the signal. ----------------------------------------------------------------- How do programs that want service from syslogd communicate with it? What commands are used, and what do the commands do? ----------------------------------------------------------------- An entry in /etc/syslog.conf reads: lpr.warning /var/spool/lpd-probs According to the entry, which level(s) of messages will be logged to /var/spool/lpd-probs? The severity levels that the machine's syslogd knows about are, in descending order, emerg, alert, crit, err, warning, notice, info, and debug. ----------------------------------------------------------------- //////////////////////////////////////////////////////////////// Questions on Chapter 02 of Nemeth -- Booting and Shutting Down //////////////////////////////////////////////////////////////// ----------------------------------------------------------------- List the main steps in the Unix booting process. ----------------------------------------------------------------- How does the operator exit from single-user mode, and allow the system to finish booting into multi-user mode? ----------------------------------------------------------------- When fsck is called from system start up files at boot time, how does it "know" which filesystems exist, and which ones might need to be checked? ----------------------------------------------------------------- Sometimes a system that is not booting properly will "magically" boot just fine if you turn off the power for 10 seconds after shutting it down. What does Nemeth give as an explanation of this? ----------------------------------------------------------------- ///////////////////////////////////////////////////////////////// PART II: Homework #2 Problems for The Kernel (Daemon) Book. Chapter 04: Process Management ///////////////////////////////////////////////////////////////// ////////////////////////////////// Chapter 04 -- Process Management ////////////////////////////////// ----------------------------------------------------------------- When and how does process scheduling interact with the memory management facilities? Put another way, what does scheduling software do to solve or avert problems that memory-management software might have? ----------------------------------------------------------------- The system raises the hardware priority to splhigh in the sleep() routine before altering the contents of a process's proc structure. Why? ----------------------------------------------------------------- What does the 4.4BSD system do to re-calculate the user priority of a process when it is awakened from sleep of over one second? Include as much detail as possible about the actual formulas used. ----------------------------------------------------------------- Often when a signal is posted to a process, that process is "set to run". Does that mean that the process that received the signal will always be the next process to use the CPU in user mode? Explain. -----------------------------------------------------------------