Re: DOS3.3 questions

[dempson@actrix.gen.nz (David Empson)]

Adalbert Goertz <be404@yfn.ysu.edu> wrote:

> I have always worked with Prodos and begin to set up games for our youngsters
> which are either DOS or something else(Pascal?).

Pascal is quite distinctive: it shows a screen full of inverse "@"
symbols when booted, followed by an inverse cursor in the top left of
the screen which usually moves between lines 1 and 2 a couple of times.
Depending on the software, it may display a "splash screen" which tells
you which version of Pascal you are running, or it might go straight to
a title screen.

Wizardry is one game that runs under Pascal.  Most of the "Apple
Presents ..." series were also Pascal-based.

> Anyway I am puzzled about the DOS games:
> Some are selfbooting, others are not.
> I have not figured out why some are selfbooting and why others are not and
> give a message
> THIS DISK HAS NO DOS TO BOOT.
> INSERT ANOTHER DISK AND PRESS A KEY TO REBOOT.

This message is displayed if you attempt to boot a disk that was
initialized using COPY II+, and no DOS was copied onto the disk.  COPY
II+ has an option in its "Copy" command to copy the DOS image from one
disk to another.

If you boot a standard DOS 3.3 disk and get into BASIC, you can
initialize a disk by removing your boot disk, inserting the disk to be
initialized, then typing "INIT HELLO" (the name "HELLO" is the standard
name for the startup program - you can use another name if you like).  

This will initialize the disk in the current drive (wiping all
contents), copy DOS onto the disk to make it bootable, and save whatever
Applesoft BASIC program is in memory as the HELLO program.  If you don't
want to keep this program, just delete it, or replace it with another
program.  (A HELLO file will be saved even if there is no BASIC program
in memory.)

> I know that in Prodos booting, the computer looks for the PRODOS file.
> What file is required to make DOS booting possible?

DOS itself is not a file.  It is stored directly onto the first three
tracks of the disk, using up 12K of the 140K available space.  (The
catalog takes up another 4K track, so you have a total of 124K available
for file storage on a bootable DOS disk.)

When Copy II+ initializes a DOS disk, it doesn't copy DOS onto the disk
(unless you do this as a separate step).  This leaves two tracks free,
giving you an extra 8K of space, but the disk is not bootable.


Note that some third-party or patched versions of DOS do not have the
INIT command available.  For example, with Diversi-DOS, you had to
initialize a disk using standard DOS, then run a program to replace the
standard DOS image with an image of Diversi-DOS.

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand