(c)  Copyright 1989 Commodore-Amiga, Inc.   All rights reserved.
The information contained herein is subject to change without notice, and 
is provided "as is" without warranty of any kind, either expressed or implied.  
The entire risk as to the use of this information is assumed by the user.



              Getting Software to Run on Hard Disks 

                      by Michael Colligon


With the growing popularity of the Amiga 500 and 2000, the use of hard 
disks is becoming increasingly more important to consider when programming 
for the Amiga.  If a user wants to run multiple applications using floppy 
disk drives, he could spend the better part of his time swapping disks, and 
thus not getting much work done.  But by adding a hard disk to the Amiga
storage capacity and system performance are greatly enhanced.

But adding a hard disk does not solve every problem.  There is no easy and 
efficient way to install application software on an Amiga hard disk.  Let's 
look at the user's options.

The novice user may try to copy the files from the application disk to the
hard disk by moving the icons over.  This has the advantage of being 
extremely easy to do for any user.  The disadvantage is that most programs 
will require files, other than the ones that have icons, in order to run.  
The application may also need an ASSIGN statement in the startup-sequence 
on the boot disk to set a required volume name on the hard disk.  This is 
no easy task for the novice user.

More advanced users may try using the command COPY DFO: to DHO: ALL.  This 
copies all of the files to the hard disk.  This is easy to do if the user
knows the CLI.  Its disadvantages are that it may over-write existing
system files or waste disk space with unneeded files.  In addition, the hard 
disk will not be very well organized.  And it may still be necessary to edit
the startup-sequence to set the correct volume name.

The experienced user will make a new directory on their hard disk and then 
use the copy command with ALL option to copy all of the files on the original 
disk to the new directory on the hard disk.  This is not really harder to do 
than the previous example, but the user must think to do it in the first 
place.  This method has the advantage that it will not over-write existing 
files and organizes the hard disk better.  Its disadvantage is that some 
files on the application disk which must be in a certain directory - like 
fonts, drivers or libraries - will end up in the application directory.  
Of course, it may also be necessary to edit the startup-sequence to set 
a volume name.

The expert Amiga user can look at the files on the application disk and 
determine which files need to be copied and where they should be placed.  
This method has the advantage of efficiently using hard disk space and 
placing the files in the correct directories.  Unfortunately, very few users
indeed will be able to accomplish this on their own.  

Here are a few examples of what would have to be done to correctly
copy some existing application programs to a hard disk.

A-Talk Plus:
 
 Program Disk:
   Create a new drawer on the hard disk.
   Copy the settings drawer and its contents to the new drawer.
   Copy the Scripts drawer and its contents to the new drawer.
   Copy the Drawings drawer and its contents to the new drawer.
   Copy the Hi-Res drawer and its contents to the new drawer.
   Copy the UNIX drawer and its contents to the new drawer.
   Copy the contents of the Fonts directory to the Fonts: on the
      hard drive.
   Copy A-Talk_Plus and A-Talk-Plus.info to the new drawer. 
   Copy for Updates, For Updates.info, and More to the new drawer.
 
 Demo Disk:
   Copy the Demos directory and its contents to the new drawer.
   Copy the contents of the Drawings drawer to the new Drawings
      drawer.
   Copy the contents of the Hi-Res drawer to the new Hi-Res drawer.
   Copy to Run Demos and To Run Demos.info to the new drawer.


Deluxe Paint II:

  Key Disk: 
   Create a new drawer on the hard disk.
   Copy the Lo-Res abd Brush drawers and their contents to the new
      drawer.
   Copy the Hi-Res and Interlace drawers to the new drawer.
   Copy Dpaint and dpaint.info to the new drawer.

  Art Disk:
   Copy the Med-Res drawer and its contents to the new drawer.
   Copy the contents of the Brush and Lo-Res drawers to their new
      drawers.

  Finishing touches:
   There are 3 files (Path, c/Sigfile, and devs/Printer) which the
      user has to decide where they are needed, it at all.
   The command "ASSIGN DPAINT: pathname" must be added to the
      startup-sequence on the boot disk, where pathname is the
      directory route to the Dpaint II drawer (i.e. dhO:Dpaint or
      dhO:Graphics/Dpaint).  The icons will have to be rearranged in 
      some ofthe drawers.



Solutions

In order to solve these installation problems, the application disk
could contain an icon driven program to copy the necessary files from
the application disk to the proper places on the hard disk.  The 
installation program would copy files that belong in specific system 
directories to the right place while program and data files would
be copied to the new application directory.  An install program could
be a simple script or a custom program.

A script file can be linked to an icon and executed via XICON.  This is 
a quick and easy way to provide a hard disk install program for your 
applications since DOS scripts are easier to write than custom programs.
However you will not be able to fully use menus, gadgets or other
graphical features in the install program since the script runs under
CLI.  A script is usually slower than a custom install program as well. 

A custom hard disk install program for each application is the most user
friendly solution.  This allows full use of the graphical user interface
and in most cases will run faster than a script.  However, custom programs 
are usually harder to write and harder to maintain.  In either case, an 
application which has a hard disk install program is superior to an
application that does not.


Alternatives

There is another alternative - a general purpose hard disk install
program that can look at an application disk and determine where files
should go.  It could also allow the user to specify the location of the 
program and data files on the hard disk and could modify the default tool 
type in the info file so that it points to the correct place on the hard 
disk instead of having to add an assign command to the startup-sequence.  
This program could be included with a hard disk backup package, so that 
the user has the ability to construct his hard disk as well as save it.

Developers should consider the use of hard disks when writing and
distributing their software.  Some software packages cannot be run from 
a hard disk, while others will not even support the hard disk for data.  
To support the hard disk properly, you should include a hard disk install
program with your application to allow the average user to quickly and 
easily copy his software onto a hard disk.   As more end users add hard 
disks to their system, this will become am increasingly important factor
in the success of your products.

