@echo off
   set VCTEST=
rem check available executables
   set VCPATH=%@search[4DVCBKUP.BTM]
   iff "%VCPATH" EQ "" then
      echo Cannot locate 4DVCBKUP.BTM
      set VCTEST=X
   endiff
   set VCPATH=%@search[4DVCBKP2.BTM]
   iff "%VCPATH" EQ "" then
      echo Cannot locate 4DVCBKP2.BTM
      set VCTEST=X
   endiff
   set VCPATH=%@search[4DVCXTRC.BTM]
   iff "%VCPATH" EQ "" then
      echo Cannot locate 4DVCXTRC.BTM
      set VCTEST=X
   endiff
   set VCPATH=%@search[4DVCXTR2.BTM]
   iff "%VCPATH" EQ "" then
      echo Cannot locate 4DVCXTR2.BTM
      set VCTEST=X
   endiff
   set VCPATH=%@search[4DVCDLET.BTM]
   iff "%VCPATH" EQ "" then
      echo Cannot locate 4DVCDLET.BTM
      set VCTEST=X
   endiff
   set VCPATH=%@search[4DVCDLT2.BTM]
   iff "%VCPATH" EQ "" then
      echo Cannot locate 4DVCDLT2.BTM
      set VCTEST=X
   endiff
   set VCPATH=%@search[4DVCREAD.ME]
   iff "%VCPATH" EQ "" then
      echo Cannot locate 4DVCREAD.ME
      set VCTEST=X
   endiff
   set VCPATH=%@search[PKZIP.EXE]
   iff "%VCPATH" EQ "" then
      echo Cannot locate PKZIP.EXE
      set VCTEST=X
   endiff
   set VCPATH=%@search[PKUNZIP.EXE]
   iff "%VCPATH" EQ "" then
      echo Cannot locate PKUNZIP.EXE
      set VCTEST=X
   endiff
   set VCPATH=
   iff "%VCTEST" NE "" then
      echo ÿ
      echo The above files need to either be in your current directory
      echo       (%_CWD)
      echo or in one of the directories specified in your PATH Environment Variable.
   endiff
rem make sure 4DOS is version 3.02 or later
   ver >&! 4DVCCHK.0
   set VCVER=%@substr[%@line[4DVCCHK.0,1],5,4]
   @del /q 4DVCCHK.0 >&! NUL
   iff "%VCVER" LT "3.02" then
      echo ÿ
      echo You must have at least version 3.02 of 4DOS. You are running version %VCVER
      set VCTEST=X
   endiff
   set VCVER=
rem
rem the following 2 checks for PK v:1.1 will delay the startup routine quite a bit.
rem remove the REM's if you want to do these checks.
rem
rem rem make sure PKZIP is version 1.1 or later
rem    PKZIP -l >&! 4DVCCHK.0
rem    set VCVER=%@substr[%@line[4DVCCHK.0,1],%@eval[%@index[%@upper[%@line[4DVCCHK.0,1]],VERSION] + 8],3]
rem    @del /q 4DVCCHK.0 >&! NUL
rem    iff "%VCVER" LT "1.1" then
rem       echo ÿ
rem       echo You must have at least version 1.1 of PKZIP. You are running version %VCVER
rem       set VCTEST=X
rem    endiff
rem rem make sure PKUNZIP is version 1.1 or later
rem    PKUNZIP -l >&! 4DVCCHK.1
rem    set VCVER=%@substr[%@line[4DVCCHK.1,1],%@eval[%@index[%@upper[%@line[4DVCCHK.1,1]],VERSION] + 8],3]
rem    @del /q 4DVCCHK.1 >&! NUL
rem    iff "%VCVER" LT "1.1" then
rem       echo ÿ
rem       echo You must have at least version 1.1 of PKUNZIP. You are running version %VCVER
rem       set VCTEST=X
rem    endiff
rem    set VCVER=
rem
rem check for config.sys
   iff not exist \config.sys then
      echo ÿ
      echo You must setup a CONFIG.SYS file. At a minimum, it must specify:
      echo     DEVICE=KEYSTACK.SYS
      set VCTEST=X
      goto VCCKMEM
   endiff
rem make sure KEYSTACK is loaded
:VCCKKEY
   inkey /w0 %%VCKEY
   if "%VCKEY" NE "" goto VCCKKEY
   keystack 255
   inkey /w0 %%VCKEY
   iff "%VCKEY" NE "ÿ" then
      echo ÿ
      echo Your CONFIG.SYS file does not specify:
      echo     DEVICE=KEYSTACK.SYS
      echo or else KEYSTACK/INKEY is malfunctioning.
      set VCTEST=X
   endiff
   set VCKEY=
rem check environment space
:VCCKMEM
   @memory >&! 4DVC.0
   set VCENV=%@substr[%@line[4DVC.0,9],13,-3]
   @del /q 4DVC.0 >&! NUL
   iff "%VCENV" LT "128" then
      set VCTEST=X
      echo ÿ
      echo You only have %VCENV bytes of available Environment Space.
      echo 4DVC requires at least 128. Change your CONFIG.SYS file and increase
      echo the "SHELL=..... /E:(enviroment-size)" entry to request more space.
   endiff
   set VCENV=
   iff "%VCTEST" NE "" then
      set VCTEST=
      cancel
   endiff