******************************************************************
**                                                              **
**             IBM PC Installation of DISGCL                    **
**                                                              **
**  Contents:  1.)  Introduction                                **
**             2.)  Check the Contents of the Disks             **
**             3.)  Installation of DISGCL                      **
**             4.)  Using Super VGA Cards                       **
**                                                              **
**  Date   :   15.01.1999                                       **
**  Version:   3.1     /  MS-DOS                                **
**  Author :   Helmut Michels, Tel.: +49 5556 979 334           **
**             MPI fuer Aeronomie, Max-Planck-Str. 2,           **
**             D-37191 Katlenburg-Lindau, Germany               **
**             E-mail: michels@linmpi.mpg.de                    **
******************************************************************

1.)  Introduction
   
     This file describes the installation of the  graphics command
     language DISGCL which is an interpreter based on the graphics
     software DISLIN.  All  DISLIN  statements can be written to a
     script file and then be executed with  DISGCL,  or can be en-
     tered in an interactive mode.

     Similar to programming languages such as Fortran and C, high-
     level language elements can be used within DISGCL.  These are
     variables,  operators,  expressions, array operations, loops, 
     if and switch statements,  user-defined subroutines and func-
     tions, and file I/O routines.

     An easy to use  interface  for data input is given to include
     data into  DISGCL  jobs.  The format  of data  files  is very 
     simple and useful for most DISLIN plotting routines.

     Several quickplots are offered by  DISGCL which are collecti-
     ons of DISLIN statements to display data with one command.

     Notes: 

      - An installation of DISLIN is not necessary for DISGCL.

      - The source code is compiled with GNU GCC 2.8.1  ported for
        IBM-PCs  from  DJ Delory. 

      - This version of DISGCL is free software;  you can make co-
        pies and redistribute it. The software is  distributed  in
        the hope that it will be useful, but WITHOUT ANY WARRANTY.

2.)  Check the Contents of the Disks

     The DISGCL distribution disk contains the following files:

     DISLIN.INF
     README.INF
     GCL_31.ZIP      
     UNZIP.EXE
 

3.)  Installation of DISGCL

     The  MS-DOS version of DISGCL is distributed as a  .zip  file 
     created with the file packaging utility ZIP (version 1.9).
     The .zip file has the file name  GCL_nn.ZIP  where  nn is the
     current version number of DISGCL.

     To install DISGCL, make the following steps:

  a) Create a temporary directory and copy all files from the
     distribution disk to the directory:

     for example:   md  c:\temp
                    cd  c:\temp
                    copy a:\*.*  *.*

  b) Extract DISGCL files with the command:

                    unzip -o GCL_31

  c) Run the install program with the command

                    INSTALL c:   (or INSTALL d:)

     The program INSTALL installs DISGCL in the directory 
     c:\DISLIN (or d:\DISLIN).

  d) Reconfigure the System

     Add the DISLIN\DJGPP directory to the PATH environment in the
     file AUTOEXEC.BAT

     for example:  PATH C:\BIN;C:\DISLIN\DJGPP;C:\DJGPP\BIN

     Define the environment variable DISLIN in the file
     AUTOEXEC.BAT:

     for example: SET DISLIN=c:\dislin

  e) Check the installation by running the examples

     Type:    disgcl  curve
       or:    disgcl  surface
       or:    disgcl  pie
       or:    disgcl  bars
       or:    disgcl  world
       or:    disgcl  contour

     The examples can be found in the directory:  \dislin\gcl


4.)  Using Super VGA Cards

     DISLIN uses by default BIOS calls to display graphics on the
     screen.  Special graphic modes can be defined with the 
     utility program  DISVID (see DISVID). This method is not very
     fast.
     
     To get fast graphical output on the screen, you can use the 
     interface of DISLIN to the GRX library of the DJGPP distribution.
     DISGCL is linked with GRX23. All you have to do is to set the
     environment variable GRX20DRV.

     For example: set GRX20DRV=et4000 gw 1024 gh 768 nc 256

     Available drivers for GRX23 are: stdvga, stdega, et4000,
           cl5426, mach64, ati28800 and VESA.
