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From: darrylo@hpsrlc.HP.COM (Darryl Okahata)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Interesting PC Hardware/Software Problem
Message-ID: <3320062@hpsrlc.HP.COM>
Date: Sat, 17-Oct-87 15:36:44 EDT
Article-I.D.: hpsrlc.3320062
Posted: Sat Oct 17 15:36:44 1987
Date-Received: Sun, 18-Oct-87 23:48:57 EDT
References: <2036@watcgl.waterloo.edu>
Organization: HP Network Measurements Div - Santa Rosa, CA
Lines: 32

In comp.sys.ibm.pc, smvorkoetter@watmum.waterloo.edu (Stefan M. Vorkoetter) writes:

> I ran into an interesting problem the other day.  A TSR that I was
> using would occasionally insist that it was already installed when
     [ ... ]
> location put nothing on the bus.  Bus capacitance held the previously
> fetched byte on the bus instead, and it was read again.  Thus, the
> bytes tested as equal.  In the changed code, the value was read first
> and stored, and then compared.  It is interesting to note that when
> I used debug on the second example and set a breakpoint after the
> MOV AX,[BX] instruction, the value in AX was not the same as what I
> saw when I looked at location DS:BX with debug.
> 
> Can anyone confirm or deny my suspicions about this?  The system I am
> using is an IBM PCjr, with a Racore Drive Two expansion and 512K of
> RAM.
> 
> Stefan Vorkoetter
> University of Waterloo
> ----------

     I've heard other people say this, too.  You are not the only one,
although I can't remember the name of the TSR that they were using.  It
does make sense, though.

     -- Darryl Okahata
	{hplabs!hpccc!, hpfcla!} hpsrla!darrylo
	CompuServe: 75206,3074

Disclaimer: the above is the author's personal opinion and is not the
opinion or policy of his employer or of the little green men that
have been following him all day.