Re: Help: Writing PRODOS disks from a MAC?

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

John Dunning <jrd@hotsprings> wrote:

> I've been helping a (mostly non-computer-literate, so far) friend get
> his IIgs configured and running.  I've downloaded a bunch of stuff
> from various archives, using my mac, and dumped them on
> prodos-formatted disks.  The IIgs can read the disks, but when I try
> to bootstrap BINSCII, by going to basic and EXEC'ing the BINSCII.EXE
> file, basic complains "FILE TYPE MISMATCH".  Other programs complain
> similarly when trying to read the files I've downloaded.

Yep.  I assume you are using a Mac which is running System 7.0 or later,
with PC Exchange?  PC Exchange bends over backwards to make sure that
all attributes of Mac files are preserved when they are copied onto a
ProDOS disk.  This means that the file will retain the Macintosh file
type, creator, and resource fork (if any).

Unfortunately, doing this involves an extension to the ProDOS file
system which is not supported by ProDOS-8, only by GS/OS (the native
IIgs operating system).  The end result is that most files copied from
the Mac to a ProDOS disk are not readable by 8-bit Apple II software
(short of using special programs to extract the data fork to another
file, which requires bypassing the operating system).

There is a workaround: PC Exchange is smart enough to recognise ProDOS
files that have been copied onto Mac disks.  When they are copied back
to ProDOS disks, they don't gain any embellishments, and are readable by
8-bit Apple II software.

It is also possible to do this with arbitrary files on the Mac, provided
the file does not have a resource fork.  You can use a file type
changing utility on the Mac (e.g. Snitch or ResEdit) to set the creator
to 'pdos' (must be in lower case) and the file type to 'TEXT'.  This
will result in a TXT file when you copy it to a ProDOS disk.

This is fine for any text file, and also for any BinSCII file (.bsc or
.bsq) or ShrinkIt file (.shk, .bxy, etc.), as neither program
particularly cares about the file type.

There are a few cases where you do need to set the correct ProDOS file
type (e.g. a IIgs self-extracting archive must be set up as a GS/OS
application) but these are rare.

Other file types are tricky, because they require entering unprintable
characters on the Mac.

> A bit of digging reveals that the mac seems to have written files with
> prodos file-type $00.

The ProDOS file type doesn't have enough bits to represent all possible
Macintosh file types and creators, so PC Exchange sets the ProDOS file
type to $00 if it cannot produce an exact match.

> My surmise is that it's supposed to be some code that signifies a text
> file.  My further surmise is that the mac wrote them with a busted
> file-type because I downloaded them with Mosaic, so the mac doesn't
> think they're simpletext files, but rather Mosaic documents.

SimpleText files (TEXT/ttxt) wouldn't be any better - they would still
end up as file type $00.  Only ProDOS text files (TEXT/pdos) will end up
as TXT files on a ProDOS disk.

> Please reply via mail, as I don't normally watch this group.

It is a bit hard to reply by E-Mail if your news article header contains
an invalid return address, you don't have a signature and you don't
include the correct reply address in the body of your text.  I tried one
obvious address (jrd@hotsprings.com) but that bounced.  Check that your
news posting software is configured correctly.

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