SH>> OS/2 starts something along the lines of X11,
 SH>> and the WPS is simply the window manager.

 ET> I thought PM (program manager) is the window manager?

Actually, OS/2 doesn't have window managers in the X Window System sense.

Just to clear up any confusion, here are some definitions:

   Presentation Manager

        A graphics library, linked to and thus shared by all PM applications.  
PM provides means for managing and drawing windows and controls on a graphics
display.  Contrary to popular misconception, Presentation Manager is not an
application in its own right.  PM is just a massive library for applications
to use.  Unlike some other operating systems, PM is an application-level
library, not a part of the operating system kernel.  (On Windows NT 4 and
later, the GDI is part of the operating system kernel.)  Strictly speaking, PM 
is not part of OS/2 itself, but is simply a handy suite of application DLLs,
shipped as part of the bundle, that happens to be used by a *lot* of
applications.  Text-mode OS/2 applications do not require Presentation Manager 
in order to run.  The one part of PM that involves the OS/2 kernel is the
low-level display driver, such as KMGAX64.SYS for Matrox display adapter
cards, that allows PM applications (indirect) access to the physical display
adapter hardware.  Everything else operates at application level outside of
the operating system kernel.

   Workplace Shell

        An application program, that uses PM for its user interface.  WPS is
the default "shell" program for OS/2 2.0 and later.  It presents itself on
screen as a collection of "objects", which can be physical files and
directories or abstract entities such as the system clock.  The default object 
to display, which is opened when WPS starts up and which cannot be closed, is
the "Desktop" folder object, which opens in icon view with its client area
occupying the entire screen (so that its title bar is hidden off the top of
the screen).  The executable file for Workplace Shell is \OS2\PMSHELL.EXE . 
The name is somewhat of a misnomer, since what it *really* means is "The shell 
program that we (IBM) wrote that uses Presentation Manager and graphics mode
rather than text mode as did the earliest shells for OS/2 version 1.0.". 
Someone obviously failed to mention to the Powers That Be that one can easily
write more than one shell that uses Presentation Manager, and indeed that
IBM/Microsoft already had written such a shell for OS/2 1.3.

 ¯ JdeBP ®

--- FleetStreet 1.22 NR
500/3