ROM debuggers (was Re: PDP-11/44 boot prompt)

From: D. Peschel <dpeschel_at_u.washington.edu>
Date: Sun Nov 1 22:17:16 1998

> "D. Peschel" <dpeschel_at_u.washington.edu> wrote:
> > Also, your claim is totally opposite from the previous claim
> > (that's what I meant by "degree").
>
> No. Totally opposite and equal in degree from the original claim that
> all Apple computers have a ROM debugger would be the claim that no Apple
> computers have a ROM debugger (or equivalently, all Apple computers do not
> have a ROM debugger). Both are universal claims.
>
> The claim that some X have Y is a much weaker claim, not at all of the
> same degree. It does not assert any common property for the entire class
> X.

Hmm... what did I mean by "totally opposite"? Well, I'm not sure so maybe
we should say you're right and drop the point. But your claim was rather
abrupt. Let's just say that substantiation always helps. I read your point
(here and in another post) about finding one counterexample -- which is true.
I would have understood your point a lot quicker if you had said, "I only need
to find one counterexample and here it is." Having the correct counterexample
is nice too. :)

> > No. Many of the older models had a plastic switch that snapped into the
> > ventilation slots; it would reset the machine or bring up a debugger.
>
> Which has nothing to do with whether the machine has a ROM-based debugger.

Well, yes, but as it happens they do have debuggers. The reason I mention the
switch is that without it one would almost certainly be unaware that the de-
bugger was there. (Unless some sort of crash caused an NMI.)

> I didn't say anything about the XL. Actually, *you* are wrong about the XL;
> I deliberately omitted the Lisa, Lisa 2, Lisa 2/5, Lisa 2/10, and Macintosh XL
> because they do have a ROM-based debugger. I've used it a lot lately.

Probably not entirely by choice, right? (as in, "Damn, here I am looking at
the debugger again... stupid memory errors... stupid hard-drive setup...
stupid copy protection...") :)

Is it more or less useful than the one in the Macintosh?

> 2. It is not clear that FORTH can be considered a debugger/monitor, any
> more than BASIC can.

hmm... FORTH gives you low-level access to memory; you could write all the
features of "real" debugging monitors if they weren't already there (e.g.,
hex dumps). I guess the potential is there, and it's there with FORTH a lot
more than with BASIC.

I want to slip this in -- I was annoyed at how completely useless the HELP
command appeared to be, so I typed SEE HELP and got something like this --
I forget the exact syntax:

        ." HELP for " print-string ." is not available." cr

Is this allowed by the standard?

-- Derek
Received on Sun Nov 01 1998 - 22:17:16 GMT