Re: DOS 3.3 & ProDOS & other Apple II OSs

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

Gabriel Morales <Togega@Concentric.net> wrote:

> What are the fundamental differences between DOS 3.3 & ProDOS to a new
> Apple II user?

The major differences that occur to me, at a user-visible level:

Without special software or a patched version, DOS 3.3 only works with
5.25" disks, and in any case a volume is limited to 400 KB.

ProDOS works with pretty much any type of drive, and can support volume
sizes up to 32 MB.

ProDOS supports subdirectories, DOS 3.3 does not.

ProDOS filenames are more restrictive: fifteen characters, using letters
digits and periods only (must start with a letter).  DOS 3.3 can use up
to 30 characters in a filename, with almost no restrictions.

DOS 3.3 has a small set of file types, while ProDOS has a large number
of unique types, which help to identify which application created a data
file.

ProDOS supports date and time stamping of files, while DOS 3.3 does not
(unless patched, which has compatibility problems and limits the length
of filenames).


Applications nearly always work with the appropriate operating system
only (in some cases with different versions for DOS 3.3 and ProDOS).  If
you have to run a particular application, you may have no choice about
which operating system to use.

> For which is there more software available?

Probably ProDOS by now, but there are an awful lot of small programs
which run under DOS 3.3.  Nearly all of them are pretty old.

In any case, a large number of DOS 3.3 programs (e.g. games) don't let
you use the operating system in any meaningful way, so you can
effectively ignore it.

Application support under ProDOS is better organised, with easy support
for program selectors, for example.

> What other operating systems are available for the Apple II (I know of
> at least the GS OS, of course)?

First a few side notes:

There is ProDOS-16, which is the predecessor of GS/OS.  From the user's
point of view, they are very similar.  GS/OS is better all round.
(ProDOS-16 only works on the IIgs.)

There are also earlier versions of DOS 3.3.  The first released version
was 3.1, but 3.2.1 was the next most common after 3.3.  Earlier versions
were pretty similar as far as the user was concerned, except that 3.3
increased the disk capacity from 113.75KB to 140KB.  Conversion
utilities are needed to go between earlier versions and 3.3 (or vice
versa).

Some programs (particularly games) have no operating system (as such) at
all, or use a proprietary self-contained one.  For example, Ultima V has
an operating system called "DinkeyDOS", which uses the ProDOS file
system but has a different application programming interface (and no
user interface to speak of).


The other major operating system for the Apple II:

Apple II UCSD Pascal, which is of a similar vintage to DOS 3.3 (1978 to
1985).

The original version (1.0) only works well on an Apple II+ with a
language card installed, but can be used on later machines.  Later
versions (1.1, 1.2 and 1.3) work well on a IIe, IIc or IIgs, while
retaining support for the II+ (possibly with patches).  Versions 1.2 and
1.3 also have extra support for 128K RAM in the newer machines.

The operating environment is entirely menu driven.  Most programs are
written in Pascal, which is compiled to an intermediate form which is
interpreted by the computer, so everything runs rather sluggishly.  The
main advantage of this method is that it allows very large and complex
programs to be used in the limited environment of a 64K Apple II.

The environment is quite powerful for programming tasks, particularly
for people coming to the Apple II from a minicomputer environment (where
UCSD Pascal originated).  The Pascal operating system also comes with an
assembler, and there was even a Fortran compiler.

The earlier versions require the use of a 5.25" drive and can support
other devices with loaded drivers.  Version 1.3 can boot from a 3.5" or
hard drive.


Other minor players:

There are also Apple II versions of CP/M, which don't run on the Apple
II per se, but actually on a Z80 card installed in a slot, with
assistance from the Apple II (keyboard, video output and disk drive
access, for example).  The 5.25" drive is used by the CP/M environment,
and there are several utilities that run under ProDOS and DOS 3.3 which
can access Apple II CP/M disks in various ways.

Various Apple II models support a variety of different Z80 cards.  There
are options for every model.


Similarly, you can run MS-DOS on a PC Transporter card.  It can use a
mixture of Apple II drives (floppies, and image files on hard drives)
and directly connected PC-compatible drives.

The PC Transporter works in an Apple II+, IIe or IIgs (with the
appropriate adaptor kit).  The Apple II actually runs ProDOS-8 while the
PC Transporter is active.


Does GEOS count as an operating system, or is it just a layer than runs
on top of ProDOS?


> On what models do these run?

I've already mentioned this for most, but in case you need extra info:


DOS 3.3 works on everything, including an original Apple II with less
than 48K of RAM.

DOS 3.2.1 and earlier can't be booted directly on any machine with the
current disk controller (you need the original card with old PROMs on
it), but can be used on any machine with a DOS 3.3 pre-boot.


ProDOS 1.0 and 1.0.1 works on every Apple II model (48K RAM required in
an original Apple II).

ProDOS 1.1 and later require 64K RAM (language card required in an
original II or II+).

Some ProDOS applications (notably BASIC.SYSTEM) require Applesoft in
ROM, so won't work on an original Apple II (unless its ROMs are
replaced).

For an Apple IIgs, ProDOS-8 1.2 or later should be used in preference to
1.1 or earlier, but the earlier versions will work.


ProDOS-16 works on any IIgs ROM version, though there may be
compatibility issues with a ROM 3 IIgs, and the earliest versions may
have problems on a ROM 01.

GS/OS requires a ROM 01 or ROM 3 IIgs.

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