On  in a message to Jon Guthrie, Carl Forester wrote:

JG> OS/2 is not DOS.  When OS/2 loads an executable program, it
JG> opens it in a sharing mode that prevents anyone from writing to
JG> it. That means that a program can't write to its own executable
JG> file.

JG> Not only that, but writing programs that save configuration
JG> information in their exe's hasn't been a good idea for a
JG> half-dozen years.  How do you handle a LAN environment where
JG> multiple people want to share the same executable, but want to
JG> configure it differently?

CF> Thanx for the answer to my question, but!
CF> This program will never be run on a LAN, so I don't see the
CF> problem with it writing to itself.

The problem comes from the way OS/2 handles physical and virtual memory
management.  OS/2 only writes _data_ to the swapper file.  Executable
code is discarded from memory entirely, and reread from disk when it's
needed again.  That could lead to some serious problems if you've
changed the code between the time OS/2 discards it and the time it reads
it from the disk again, so OS/2 makes sure that you can't do that.


Ed Blackman

... Windows 3: The Network Consultants Full Employment Act of 1990.
--- Blue Wave/Max v2.12 [NR]