# 3.3 Running VMS MATLAB 4.1.1 and MATLAB 3.5

## Problem

The MATLAB environment consists of MATLAB and TOOLBOX logicals which are defined on a system-wide basis. In order for two versions of MATLAB to run successfully in the same environment, these logicals should be defined as process-specific rather than system-wide.

## Solution

The MATLAB environment which needs to be modified to run different versions of MATLAB consists of two logical names.

  MATLAB
  TOOLBOX

When installed as described by the installation document, the logical names are defined on a system wide basis at boot time through the execution of MATLAB:[ETC]MATLAB_SYSTARTUP.COM from SYS$MANAGER:SYSTARTUP_V5.COM. (See Installation Guide step 8)

Symbols used to invoke MATLAB and its utilities, such as CMEX, are defined on a per-process basis through the execution of MATLAB:[ETC]MATLAB_SYLOGIN.COM from SYS$MANAGER:SYLOGIN.COM at login time. (See Installation Guide step 9)

A user wanting to maintain a MATLAB v3.5 environment and have the ability to run MATLAB v4.1.1 should omit steps 8 and 9 of the installation procedure. Instead, following completion of the installation procedure perform the following steps using the editor of your choice:

- Copy the lines from MATLAB_SYSTARTUP.COM which define the Logical names MATLAB and TOOLBOX to MATLAB_SYLOGIN.COM. The lines in MATLAB_SYSTARTUP.COM look like this:

    $ DEFINE/SYSTEM/EXEC/TRANS=CONCEALED MATLAB DISK$USER:[MATLAB.]
    $ DEFINE/SYSTEM/EXEC/TRANS=CONCEALED TOOLBOX DISK$USER:[MATLAB.TOOL
    BOX.]

  Place these lines so they are the first commands to be executed by the file.

- From these lines remove the "/SYSTEM" qualifier, so they look like this:

    $ DEFINE/EXEC/TRANS=CONCEALED MATLAB DISK$USER:[MATLAB.]
    $ DEFINE/EXEC/TRANS=CONCEALED TOOLBOX DISK$USER:[MATLAB.TOOLBOX.]

  Save MATLAB_SYLOGIN.COM and exit. (Do not save MATLAB_SYSTARTUP.COM.)

- Now to setup the environment to run V4.1.1 simply type:

    @DISK$USER:[MATLAB.ETC]MATLAB_SYLOGIN

(c) Copyright 1994 by The MathWorks, Inc.