Microsoft KB Archive/114578

{| The information in this article applies to:
 * width="100%"|
 * Microsoft Windows NT operating system version 3.1
 * Microsoft Windows NT Advanced Server version 3.1

SUMMARY
This article discusses the Presentation Manager (PM) subsystem for Windows NT. It is divided into these parts:


 * What is the PM Subsystem?
 * Using the PM Subsystem
 * Services Offered by the PM Subsystem

What is the PM Subsystem?
The PM subsystem enables users to run 16-bit OS/2 Presentation Manager applications under Windows NT with no code changes needed. It enables ISVs and OEMs who have invested in developing PM applications for OS/2 1.2 and 1.3 to run their applications under Windows NT. The current release of the PM subsystem will only work with version 3.1 of Windows NT and Windows NT Advanced Server.

Using the PM Subsystem
The PM subsystem is started by running PMSHELL.EXE. PMSHELL.EXE must be executed before any PM applications can be run. The PM subsystem will not start automatically upon executing a PM application, like the 16-bit Windows-on-Windows (WOW), POSIX, or OS/2 subsystems. When executing a PM application, the Win32 desktop is replaced by the PM desktop. When using the Win32 desktop, PMSHELL will appear as a minimized icon on the Win32 desktop.

- Starting PM applications

Any PM application can be run from a Program Manager icon, File Manager, or CMD command prompt. To start a PM application without switching to the PM subsystem, you can create a Win32 Program Manager icon with the "Run minimized" option enabled. The application will be active when you switch to the PM subsystem.

- User interface with PM subsystem

The user has the ability to manipulate the windows under PMNT just as they would under regular OS/2 PM. They can maximize, minimize, resize, and close windows as normal. Cutting and pasting between PM applications happens as normal, in all three formats: text, bitmap, and metafile; however, when cutting and pasting between PM and Win32 applications only text and bitmap formats are supported. The PM Task Manager is available as normal, with one addition: a "Shutdown PM" button has been added below the "Switch to" and "End Task" buttons.

- Switching from the PM to Win32 desktop

The user can switch from the PM desktop to the Win32 desktop in 3 ways:


 * 1) Using  switches to the Win32 desktop, and brings up the Win32 Task Manager. All active applications, including PM applications, are displayed in the list.
 * 2) Using  sets the focus to the next Win32 application, thereby switching to the Win32 desktop.
 * 3) Using  switches to the Win32 desktop then displays the switching title bar, allowing the user to choose the application to switch to.

- Switching from PM to Win32 desktop All running PM applications show as minimized Win32 CMD icons, and also on the Win32 Task List. Double-clicking a PM application icon or choosing a PM application from the Task List switches the display to the PM desktop.

- Exiting a PM application

PM applications should be exited by the normal PM manner, by choosing the Close option of the applications system menu or another Exit option provided by the application.

If the user chooses to close the application by any other method, the PM subsystem may require him to interact with the application, or may generate a Win32 dialog with the "Wait," "End Task," and "Cancel" buttons. This dialog should not be used to close the application, therefore the user should always choose "Cancel" if confronted with this dialog in regards to a PM application.

- Terminating the PM subsystem

The recommended way to shutdown the PM Desktop is to choose "Shutdown PM" from the PM Task Manager, and the PM subsystem will generate a confirmation dialog with the "Shutdown" and "Cancel" options. If the user chooses to close the subsystem by selecting "End Task" from the Win32 Task Manager, a Win32 dialog will be generated with the "Wait," "End Task," and "Cancel" buttons. The user should NOT choose any of these options. The display should automatically switch to the PM Desktop, where the "Shutdown" and "Cancel" confirmation dialog should be presented. After "Shutdown" is selected, the PM Desktop will close, and the Win32 Desktop will return. However, the former dialog will still be present. The user should ALWAYS choose "Cancel" from this dialog to ensure the PM subsystem will close properly.

- Abnormal Termination

If the PM Desktop appears to be hung, or PM applications do not appear to start, the PM subsystem may need to be terminated. First, determine if the Win32 subsystem has been affected. To do this, press the NumLock key on the keyboard. If the NumLock light still toggles on and off, the Win32 system is still active, attempt to switch to the Win32 Desktop and allow 5 minutes for the system to react. If the display does not switch after 5 minutes, reboot the machine.

If the Win32 Desktop is still accessible, then terminate all OS/2 character- mode applications and PM applications, using the Win32 Task Manager's "End Task" option or by closing the Win32 windows that represent them. If a Win32 dialog appears with the "Wait," "End Task" or "Cancel" appears, then choose "End Task." NOTE: This is an exception to the previously stated rule, that the "End Task" selection should never be chosen for a PM application. After all OS/2 applications are closed, perform the same steps on PMSHELL. Then, using the KILL.EXE utility from disk #1 of the PMNT release disks, execute "KILL OS2SRV." This will terminate the OS/2 subsystem in NT. Upon executing any OS/2 application, command line or PM, the OS/2 subsystem will restart. If the OS/2 subsystem will not terminate, then a reboot of the system may be required.

Services offered by the PM Subsystem
Printing:

The PM subsystem supports printing on local or remote printers. The PM subsystem only supports using PMPRINT, not the LMPRINT queue driver. Remote printers have to be connected using the "net use" command from a Win32 window. Print notifications appear as a WinPopUp, so the display switches to the Win32 Desktop. NOTE: Direct hardware access is not allowed, so some printer drivers may not work properly.

The PM Subsystem supplies the following PM print drivers:

- Generic postscript Print Driver, which supports a variety of postscript

printers - EPSON Print Driver, which supports several EPSON (and compatible) printers - IBM 51523 Graphics Printer 2 (and compatible) Print Driver (please note that this particular PM print driver makes extensive use of CLI/STI and  thus runs significantly more slowly on the PM Subsystem than it would  under OS/2 1.x). - HP LaserJet Print Driver System Utilities:


 * Desktop Manager. PMNT does not supply a Desktop Manager. The user is expected to execute his PM applications from icons and groups in the Win32 Program Manager. Applications which modify groups will modify the Win32 program groups.
 * Task Manager. Both the PM and Win32 Task Managers are available under the PM Subsystem, access is described above.
 * Control Panel. Time & Date works on the system time. Changing the mouse to Left-hand in Win32 Control Panel affects PM applications as well. Cursor Blink, Double Click, Screen Colors, Border Width, Warning Beep, Mouse, Country, COM Port Configuration, Add/Delete Printer/Queue Driver and Add/Delete Font affect PM applications only.
 * Print Manager. The OS/2 Print Manager is supplied with virtually no changes.
 * File Manager. No File Manager is supplied with PMNT. The Win32 File Manager should be used for handling files.

REFERENCE(S)
Microsoft Windows NT- PM System Overview, April 1994
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Last reviewed: May 15, 1997

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