What is the use of vsvars32.bat and vcvars32.bat?

I have a old batch file written years ago by one of the developers to build a C# and VC++ projects of our application.

In this batch file I am not able to understand why is the vscars32.bat and vcvars32.bat called in the batch and what's its use in the batch file.

I know the Devenv command is used to build .net projects and Msdev command is used to build the VC++ projects but i am not able to figure out why the another batch files are called in it.

Also wanted to know does the Devenv and MSdev commands requires its respective IDE installed on the server to run this?

Below is the batch file -

@echo off

rem define the build log file
Set MsgLog=ReleaseBuildLog.txt

rem delete the old log
del %MsgLog%

echo ================= Starting build process =================
echo Build messages stored in %MsgLog%
echo ==========================================================


call "C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\Tools\vsvars32.bat" 

echo Compiling Wipe
devenv .\0C#\Wipe.sln /Rebuild "Release|Any CPU" >> %MsgLog%
if errorlevel 1 goto err

echo Compiling Admin
devenv .\0C#\Admin.sln /Rebuild "Release|Any CPU" >> %MsgLog%
if errorlevel 1 goto err


echo Copying DotNet assemblies and generating tlb files 
call Release_DotNet_Assemblies_Copy.bat
if errorlevel 1 goto err


echo building telliEvent...
msdev .\tellievent\tellievent.dsp /MAKE "tellievent - Win32 Release" %1 %2 %3  >> %MsgLog%
if errorlevel 1 goto err

echo rebuilding SISRVANY...
devenv .\SISRVANY\SISRVANY.sln /Rebuild "Release" >> %MsgLog%
if errorlevel 1 goto err


call "C:\Program Files (x86)\Microsoft Visual Studio\VC98\Bin\vcvars32.bat"


echo building Utils...
msdev .\Utils\Utils.dsp /MAKE "Utils - Win32 Release" %1 %2 %3 >> %MsgLog%
echo building PSICal...
msdev .\PSICal\PSICal.dsp /MAKE "PSICal - Win32 Release without common" %1 %2 %3 >> %MsgLog%
if errorlevel 1 goto err

echo Build process completed.
goto end

:err
echo Build failed! Check end of %MsgLog% for details.

:end
pause
endlocal