AL> A DLL used by multiple OS/2 processes, will only be loaded once. Right?

Usually that is true.  However, if the preferred load address for the DLL
is already used in some processes that need the DLL, then it may have to be
loaded additional times.

 AL> An EXE running in multiple OS/2 processes, like a
 AL> mailer/BBS in a multi-line situation, will be loaded
 AL> again for each process. Right?

OS/2 shares executable code pages for both EXE and DLL files. If there is a
process running PROGRAM.EXE and you start a second process running
PROGRAM.EXE, additional memory for process and thread control blocks, file
handles, stacks, and read/write data areas will be allocated.  The actual
executable code in RAM will be shared between all processes running
PROGRAM.EXE.

 AL> If the above two observations are correct, it'd be rather unfortunate,
 AL> wouldn't you agree? For instance UNIX only loads a
 AL> program once, you can even give it a 'sticky bit'
 AL> attribute, forcing it to stay in memory all the time,
 AL> even if no processes use it at a particular time
 AL> (imagine a BBS program, called by getty).

There is no "sticky bit" in OS/2, but it is easy enough to
simulate this simply by blocking a thread on a named semaphore or some
other IPC object so that you can cause the process to terminate if you want
to release the memory.


--- Maximus/2 2.01wb