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From: bson@rice-chex.ai.mit.edu (Jan Brittenson)
Newsgroups: comp.sys.handhelds
Subject: ***READ THIS***: HP-48 fatal bug in VISIT
Message-ID: <16710@life.ai.mit.edu>
Date: 28 Jun 91 07:37:36 GMT
Sender: news@ai.mit.edu
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   The following crashes my Rev D HP-48, wiping out the memory, almost
every time I try it.


1. Enable error beeps ("BEEP" in the MODES menu).

2. Store a large program in a variable (one that takes 20+ seconds to
   VISIT).

3. VISIT the variable.

4. While the HP-48 is formatting for the edit, press first blue-downarrow
   and then up-arrows until it starts beeping. Keep pressing while it beeps.
   The uparrows seem to have to follow the blue-downarrow pretty quickly.

5. Watch garbage appear on the display after a while.

6. At the Recover memory? prompt, press YES. All is now gone.


   Note that the beeper must be enabled. The clock does not appear to
be making any difference.

   It seems the garbage appears on the display about when it should be
done with the ASCII conversion. Sometimes no garbage appears and the
calculator just hangs - that seems to be dependent on the program
size. The more keys are pressed after the buffer is full, the greater
the likelihood of a crash - when it occured to me the first time I
only pressed three, maybe four, extra keys.

---

   I didn't crash the HP-48 in 7 weeks, even even while working in ML.
Then it crashes all by itself during an edit, taking a bunch of RPL
programs I hadn't yet backed up along with it. Groan.

I'm interested in knowing whether others can reproduce this.

						-- Jan Brittenson
						   bson@ai.mit.edu