After selecting "Restart Desktop", a dialog box similar to the one of the Extended Shutdown will appear. The difference is that after all windows have been closed, not the whole computer is restarted, but only the Workplace Shell Process (PMSHELL.EXE).

To understand the difference it might be helpful to know that the &os2; user interface is structured into three "layers", so-to-say, which sit on top of each other:

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   ³  Workplace Shell (WPS)      ³
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   ³  Presentation Manager (PM)  ³
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   ³  OS/2 Kernel                ³
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The Presentation Manager (PM) is responsible for the graphics on your system, such as windows, icons, menus, pictures, and a few more non-graphical things, such as INI files. &os2; can run text-mode applications (e.g. the &os2; command line, CMD.EXE) without PM, but all other applications require that PM be running. A typical PM application is Netscape, for example.

The Workplace Shell (WPS) is just another, however very complex PM application. It is responsible for displaying folders, starting programs when you double-click on their icons, associating files to programs, in short: everything you see after your &os2; has finished booting. This is the context in which &xwp; is running.

The "Restart Desktop" menu item now terminates the topmost layer of the aforementioned three only, the Workplace Shell. This takes a lot less time than rebooting your whole computer, because PM and the Kernel need not be reloaded and initialized.

Restarting the WPS can be helpful when your system has become really slow (for some reason, at least judging from my personal experience, the WPS eats up more and more memory when you work with files a lot) or if you have installed software which changes WPS classes.

Important notes:

• Please keep in mind that this is not the way of restarting the Workplace Shell that IBM intended when developing it. "Restart Desktop" forces the WPS to restart by simply terminating it. Since &xwp; is part of the WPS process, it can simply exit. &os2; will then restart this process automatically. The result is almost the same as if the WPS had crashed and was restarted, although the WPS data will be saved before restarting.
  
• On my system, the icons of executables in folders get scrambled after a Desktop restart. This applies to all program objects and executable files which are not assigned an individual icon to (via their Settings notebooks). Either icons get completely lost or wrong icons are displayed. This is a bug in the Presentation Manager, on which I have no influence. After a complete reboot, the correct icons are restored.
  
• Neither Presentation Manager nor &cfgsys; settings are re-read upon restarting the WPS. If these settings have changed, a Desktop restart will not recognize these changes. Reboot instead.
  
• As a general rule, the more WPS classes you have installed, the more problems are likely to arise when restarting the WPS. This can be due to many reasons, which I don't fully understand, but for one certain third-party WPS classes do not seem to clean up allocated resources properly when the WPS is terminated. Second, the SOM kernel does seem to get confused sometimes with WPS class replacements, and some parts of the WPS then crash about 20 seconds after the Desktop has been populated.

  In these cases, you will be reported fairly random crashes in certain DLLs, which are just symptoms of something going wrong internally. If this happens, you will have to reboot. Candidates for these random DLL crashes that I have unveiled are INSTALL.DLL (contains WPInstall), WPPRINT.DLL (contains the printer and spooler classes), and also the WorkFrame which comes with the various IBM compilers. (Amusingly, all those DLLs have been programmed by IBM.)
  

• Depending on your system, the number of Desktop restarts you may successfully execute will be limited. Some users have reported that this works only once, on my system I've successfully restarted the WPS many times (about 30) before the system crashed. (This sounds like many times, but when programming &xwp;, this is necessary, unfortunately.)