[cs615asa] HW3 notes

[Jan Schaumann]

Hello,

I've sent out grades for HW3; if you have not received a grade, please
let me know asap.

A few notes on common issues or problems:

Most of your submissions do not match the plain text guidelines provided
to you at https://www.cs.stevens.edu/~jschauma/615/text.  Readability is
important.  Please try to do better in the future.  The easiest way to
ensure this is to use a simple text editor, e.g. vi or vim.  Please use
line breaks at between 50 and 80 characters.


The homework instructions explicitly noted: "For each of the questions
below, answer in as much detail as needed; elaborate on anything non
obvious or noteworthy. Do not merely provide a single answer, but
include in your response how you determined your answer."

In order for me to see what you may have learned, how you tried to solve
the problem, or what kind of thought process you had, it is critical
that you provide me with some information.  As mentioned in class, the
assignments' objectives are not for me to get the specific result, but
to see how you learn, if you have put some independent thought into it.

For almost all of you, I would have liked to see a bit more detail
showing that you did not merely performed the tasks, but that you tried
to understand them and the differences across the platforms.


You were asked to install the same software on three different systems
and observe how many files were installed.  On at least one system, the
total number of files installed is over 10 times that on the others, yet
the number of packages installed is not drastically different.  Almost
nobody commented on this.


Some of you tried to work with the FreeBSD AMI I specified, ran into
some problem, and then used a different AMI.  That's not what the
assignment asked you to do.  Worse, you did so without asking any
questions.  There's a reason I pick the images, and the problems you
encountered are to be overcome, not avoided.  Working with systems where
things are unexpectedly broken is a critical part of the daily routine
in system administration.  If you run into problems, do not make
assumptions; describe your problem on the class mailing list and ask for
help.


Some of you answered some of the questions in a hand-waving and short
manner.  For example, when I ask "Can you do this without using any
package manager at all?", then an answer along the lines of "Sure, I
just didn't, because I found it annoying." is not quite what I'm looking
for.  The fact that I'm asking the question should give you a hint that
there's likely a bit more to it than a simple 'yes' or 'no' answer.
Similarly for when you try to install software from source; several of
you said, effectively, "I tried, didn't work well, so I gave up", which,
again, is not a good way to score points here.

Just like when solving e.g. a math problem, you need to show your work.
Show me you thought about this, that you understood what I'm asking, why
I'm asking.


The last section gave most of you the biggest problems, and again many
of you did not provide sufficient detail in your answers.  When asked
how you might know if what you installed was not compromised, answering
in a single sentence "You can't know that." is not sufficient.  If there
is no way of knowing this, then do we just close our eyes and hope for
the best?  Is there no way of gaining _any_ assurance?  What I'd be
looking for here would be a bit of an analysis of the steps you took and
what's involved, at what steps you _can_ detect problems.


-Jan