On PEEKing and POKEing Around
=============================
joel dinda
[75725,1134]

Once again:  PEEKs are always safe.  POKEs have risks, but can be
instructive.

Phil Wheeler insists that I've overstated the dangers involved when
I call his TDDMON a "DANGEROUS" program (I do so in SECTR0.TDD, in DL5).  He's
correct; the caution's left over from a previous version and I'd intended to
soften it.  Since I've no plan for a further rewrite of SECTR0, I'll add
some pertinent comments here, instead.

Even a casual perusal of SECTR0 should convince anyone that I've no aversion
to PEEKing and POKEing around.  Indeed, a great deal of the information there
was gathered by making systematic POKEs and observing the resulting behavior
of the drive.  These experiments are both interesting and necessary if one
expects to learn how a computer and/or its accessories work.  TDDMON is a
convenient tool for such explorations, DON'T let my caution scare you off.

There are risks, however.  One risk is that you'll cold start your computer
itself.  The other important risk involved in TDD explorations is that
you'll render a floppy disk useless-until-reformatted.  NEITHER of these
risks needs prove fatal; reasonable precautions (keep the computer empty
and only work on COPYd disks) should render disk crashes nearly painless
and RAM crashes simply irritating.

The "dangers" depend on the user, methinks.  Bank 2 on this computer
crashes pretty frequently -- I use it hard and I like to experiment.
And over the past few weeks I've wiped out many disk directories -- and
reformatted the disk, and continued to experiment.  (I DO back files up two or
three times a day.)  For someone less comfortable with cold starts, TDDMON is
indeed dangerous -- but probably those folks aren't reading SECTR0.

The bottom line:  If, using TDDMON or any other appropriate tool, you learn
something new about how TDD works, I'd certainly like to hear about it.

Thanks.
joel