-=> Quoting John Kismul to Rick Collins <=-
-=> FidoMail to 1:163/215, please.-=<
JK> @MSGID: 2:211/37 5dfe58cc
RC> Will it?  Why?  Where in memory?  What causes the IP to point to
RC> those particular memory addresses?
RC> I know the answers to those questions.  Do you?
JK> I know the answers, and here they come.
JK> Answer ONE:
JK> You asked "Will it?"
JK> And I answers, Yes it will.
Incomplete.  You stated "with a virus in memory".  A virus in the
disk read buffer will _not_ infect the system because the contents of
the disk read buffer are not executed.
JK> Answer TWO:
JK> You asked "Why?"
JK> And I answers, Because when the VIRUS is active in memory
JK> it checks all the files that gets executed or accessed, and
JK> if the virus finds a file it want to infect it will infect
JK> it. 
You have changed your position.  You now are stating "the virus is
_active_ in memory".  Your original post said only "in memory".  The
key element here is "active" - and the fact that you didn't mention
that point is _why_ I asked "where in memory" and "what causes the IP
to point to those addresses".
JK> Answer THREE:
JK> You asked "Where in memory?"
JK> And I answers, What do you mean about where in memory?
JK> Where the virus is?  It is normaly located in those 640 Kb
JK> of DOS memory. 
JK> Answer FOUR:
JK> You asked "What causes the IP to...."
JK> And I answer, The IP register points to the next command
JK> or thing that your PC is supposed to do, and if you change
JK> it your PC will probably do nothing, or it will do
JK> something, what ever that is. 
Which doesn't answer the question.  The answer, of course, is because
the virus is _active_ in memory, by definition, the IP will point to
and execute the virus instructions.  The point of that question was
to lead you to the point of saying or appreciating that the virus
must be "active" - meaning that the CPU will, at some point, execute
the virus instructions, and simply being "in memory" wasn't enough.
For example, when you quit your comm program and exit, that program
is still "in memory".  All of the instructions are there - but the IP
will not point to those addresses and therefore the program will not
execute.
TTFN. Rick.
Ottawa, ON 4 Jan 19:28 
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