Re: Converting DOS 3.3

[Rubywand <rubywand@swbell.net>]

Bob and Linda Barrett write ...
> 
> Can you convert DOS 3.3 applications into ProDOS format so that they can
> be run as a ProDOS application?

 ....

     Lots of times you can. Below are snips from our Apple II
comp.sys.apple2 DOS 3.3 and ProDOS FAQs on Ground.

ftp://ground.isca.uiowa.edu/2/apple2/Faqs
http://ground.isca.uiowa.edu/2/apple2/Faqs


>>


037- How can I convert DOS 3.3 wares to run under ProDOS?

     Quite a few DOS 3.3 programs will run fine under ProDOS with no
change at all. Unless you have some reason to believe a DOS 3.3 program
will not run under ProDOS, it's worthwhile to just copy it to a ProDOS
diskette and give it a try. Since DOS 3.3 programs which do direct
writes can, possibly, damage a ProDOS disk (see Question 22), be sure to
run any risky-looking tests from a booted ProDOS diskette for which you
have a backup.

     The main barriers to running DOS 3.3 programs under ProDOS are ...

1. Size: DOS 3.3 leaves more space for programs than ProDOS +
BASIC.SYSTEM. Some DOS 3.3 programs are too large for ProDOS. To use
them you will need to find ways to reduce program size.

2. Areas of memory used: ProDOS reserves parts of memory, such as Text
Page 1 ($0400-$07FF), for various pointers. Some DOS 3.3 programs LOAD
or BLOAD into one or more of these areas. For example, some games BLOAD
a lo-res pic or Text for you to look at while the rest of the game
loads. Normally, ProDOS will refuse to do such loads and the result will
be a BUFFERS NOT AVAILABLE error message. To run these programs you will
need to unmark the reserved areas which get in the way and/or change the
location(s) of the program's troublesome LOADs and BLOADs.

When ProDOS loads it uses most of the memory in the "language card"
areas. Some DOS 3.3 programs also use this memory. If a DOS 3.3 program
uses the "language card" it will probably have to be modified in order
to run under ProDOS.

ProDOS handles buffer allocation differently than DOS. If a DOS 3.3
program lowers HIMEM in order to create space for BLOADing code or data,
it may need to be modified to guarantee that the area is safe. (See page
237 of Exploring Apple GS/OS and ProDOS 8 or page 7-4 of Beneath Apple
ProDOS.)    
3. Names: DOS 3.3 file names can be longer and have more kinds of
characters than ProDOS names. If a DOS 3.3. program BLOADs, WRITEs, etc.
to any files, you will need to be sure that the file names used are
compatible with ProDOS.

4. Commands and Syntax: There are, really, very few DOS 3.3 command and
syntax differences likely to cause problems under ProDOS. Still, there
are a few and you will need to check for these and make any indicated
mods.

5. Integer BASIC: Int BASIC programs can be transferred to a ProDOS
diskette; but, you can not run them directly under ProDOS. If you are
willing to move an Int BASIC program to a Text editor, convert the
syntax to Applesoft BASIC, and EXEC the resulting Text file, you can
obtain an Applesoft BASIC program which you can modify as necessary for
ProDOS.

6. It's not DOS 3.3: Very old software, old commercial copy-protected
software, and deprotected copies of old software may not be on DOS 3.3
disks. Your first challenge with such software is getting it into a form
which will permit transferring files to a ProDOS diskette.

     When checking and modifying a DOS 3.3 program for ProDOS a good
program editor is essential. You will save untold hours of work when you
invest in Beagle's tried and true "Program Writer".


_________________________



From: Jeff Blakeney

038- How can I modify ProDOS to do BLOADs in the input buffer
     and Text Page 1 areas?

     You can use a POKE 48984,192 to modify the bit map. This protects
pages $00 and $01, and unprotects pages $02-$07.

Note: Because the firmware and I/O cards make use of the "screen hole"
bytes in the $0400-$7FF area, BLOADing over these can interfere with
some devices.

For this reason, it is best to have special DOS wares on a separate
ProDOS diskette with a STARTUP program which does the POKE 48984,192.
This way you will know that the system has been changed to run the DOS
wares and not inadvertently try to run a program like Appleworks, etc..
under the modified ProDOS. 


-------------------------


From: David Empson

A safer method is to BLOAD the file elsewhere, and copy data onto the
text screen in a loop, copying 120 bytes and skipping 8 bytes, repeated
8 times.

_________________________

 ....


040- What are some good ProDOS references?

ProDOS Books

 ProDOS Technical Reference Manual  from Apple (Addison-Wesley)
 Beneath Apple ProDOS  by Worth & Lechner
 Exploring Apple GS/OS and ProDOS 8  by Little
 ProDOS Inside and Out  by Doms and Weishaar


<<
      


> I was using the convert program from Apple's ProDOS Utilities to try and
> convert some DOS 3.3 applications into ProDOS, but the files it created
> were not application programs.  I think it is now a Binary file instead
> (the icon showed up as a document with 1's and 0's on it under the GS/OS
> Finder.)  I tried running BinSCII on it, but to no avail.  Do I have to
> have another program to translate binary files?  Or is it not even
> possible to change formats in the first place?
>

     ProDOS SYS files have to follow a few special rules. I've never
tried the convert utility you mention; but, it does seem unlikely that
it would try to convert all DOS 3.3 binary files into ProDOS SYS files.

     A good way to deal with DOS 3.3 binary files you want to execute
under ProDOS is to BRUN them. You can do this from a program selector
under ProDOS-8 using the "-" smart RUN command. Another option is to
create a short BASIC program which does the BRUN.



Rubywand