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From: jnall%FSU.BITNET@cunyvm.cuny.edu (John Nall 904-644-5241)
Newsgroups: comp.os.minix
Subject: Trace System call for Minix
Message-ID: <6255@louie.udel.EDU>
Date: 6 Jan 89 01:24:21 GMT
Sender: mmdf@udel.EDU
Lines: 27

As part of a questionnaire that I gave my Fall class in Operating Systems,
which uses Minix for lab exercises, I asked for ways in which the course
might be improved.  One response was that it would help students to learn
how the operating system works if there were some sort of trace function
in Minix -- some way to "step through" the system.

It occurs to me that this would not only be nice, it should not be very
hard to do.  Essentially, a "trace" system call would be added, and the
student would use it at points where he needed to stop the world and look
at it.  That is, a student might put such a system call in a strategic
place within fs, and build a new system.  When it was booted up, it would
enter trace mode when it got to that point.

The system call itself would essentially just be the logical equivalent
of a breakpoint call in debugging an application program.  That is, it
would allow the display of certain items, give certain information, etc.
At some point, the student could do a GO and continue normal operation.

Before I reinvent the wheel (or try to get a grad student to do it), has
anyone already done this?  Or are there some real show stopping problems
that I'm just not seeing??

Thanks for the help.

John Nall (jnall@rai.fsu.edu BITNET)
Computer Science Department
Florida State University