The Curator is working smoothly again

Stephen Edwards (edwards@CS.VT.EDU)
Mon, 12 Mar 2001 16:00:17 -0500

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Message-ID:  <3AAD38E1.A9BF9E3@cs.vt.edu>
Date:         Mon, 12 Mar 2001 16:00:17 -0500
From: Stephen Edwards <edwards@CS.VT.EDU>
Subject:      The Curator is working smoothly again

Some students were still experiencing Curator difficulties earlier this
afternoon. The problems have now (hopefully) been permanently fixed.

In effect, there were difficulties with handling program "crashes", i.e.,
when a student program would halt because it tried to take the car of an
empty list, or did something else that would cause a run-time error. If
you are working interactively, this is the kind of situation that would
give you an error prompt so you could try to figure out the problem.

We designed the grading scripts for the Curator so that such an error
response (and the associated "restart" behavoir) was turned off for batch
grading of student programs. Unfortunately, it didn't work as well as
it was supposed to. At the same time, the Curator times all submissions
and attempts to "kill" errant processes that exceed the time limit.
Not surprisingly, this wasn't working properly for Scheme programs
either :-).

Now both problems have been fixed. Student programs that produce run-time
errors now terminate properly (but without any messages). If you
submit a program and get a low score accompanied with only part of
an output file, instead of the whole thing, then your program
crashed on the input and only the output produced before the crash is shown
in the message. Alternatively, if your program fails to terminate (or
takes too long), then you'll get back an e-mail message with a score
of 0 and a message indicating your program did not terminate within
the allowed time.

By now the Curator has churned through the backlog of submissions
and everyone who has submitted assignments since Fri should have
received an e-mail grading message for each submission.

                                -- Steve

--
Stephen Edwards            604 McBryde Hall          Dept. of Computer Science
e-mail      : edwards@cs.vt.edu           U.S. mail: Virginia Tech (VPI&SU)
office phone: (540)-231-5723                         Blacksburg, VA  24061-0106
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