 POPDOWN - A way to get to the DOS prompt from application programs.
 
 History
   Version 0.5 - February 1987
   Version 0.55 - Feburary 1987
   Version 0.6 - March 1987 - Current Version
 
 Function
   Ability to pop-down to DOS from application programs.
 
   The program will set aside a portion of your memory on start-up as a
   buffer that POPDOWN will maintain for you to allow you to execute
   other programs after popping-down to the DOS prompt from your suspended
   application program. The size of the buffer is determined by a parameter
   when you start POPDOWN.
 
   To return to your suspended application program you would type
   EXIT at the DOS prompt.
 
 Tips and precautions using POPDOWN
 
   Do not load any RESIDENT application in the POPDOWN buffer.
   Doing so will surely destroy the integrity of the DOS memory allocation
   chain. All other resident software must be loaded in the primary DOS
   buffer.
 
   Do not load BASIC in the POPDOWN buffer if BASIC is currently
   suspended in the primary buffer.
 
   If you use DOSXSERV you will need release V0.96.
 
   POPDOWN uses the environment that is active when POPDOWN
   is installed. Therefore for best results you should start POPDOWN
   AFTER you set your system prompt or change your path ect.
 
 
   POPDOWN uses the value of the environment variable COMSPEC to determine
   the path to COMMAND.COM. It will use the value of COMSPEC that
   existed just prior to being loaded for the duration of execution.
   It is therefore suggested that POPDOWN be run AFTER setting the
   COMSPEC environment variable.  For optimum use, it is suggested
   the COMSPEC be set to a RAM disk drive.  This will cause
   POPDOWN to be run instantaneously with each press of the HOT-KEY.
   There will be no delays waiting for COMMAND.COM to be loaded
   from floppy or hard disk.
 
  POPDOWN now supports Control-Break while popped down. That is
  to say that when you HOT-KEY to DOS from your application program
  Control-Break functions normally.
 
   Example
     (Assume D is a RAM disk)  This could be in an AUTOEXEC.BAT file or
     entered at the DOS prompt.
 
     copy a:command.com d:\
     set COMSPEC=D:\COMMAND.COM
     popdown
 
 Example
     C>popdown x 128        <----- starts POPDOWN with CTRL-X as
                                   HOT KEY SEQUENCE to pop-down.
                                   POPDOWN buffer size would be 128k.
                                   (installed message is displayed)
 
 
     C>write                <----- Start IBM Writing Assistant.
 
           <     While running IBM Writing Assistant      >
           <     press CTRL-X to return to DOS.           >
 
     C>                     <----- Run another application or DOS command.
                                   To return to IBM Writing Assistant
                                   type EXIT at the DOS prompt and press
                                   enter.
 
 
     For more information and examples run POPDOWN like this:
 
     C>POPDOWN ?

