Re: PRODOS 8: What is the latest version?

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

In article <4f61oq$1ke@lynx.unm.edu>,
stephen e buggie <buggie@argo.unm.edu> wrote:
> 
> The latest version of ProDOS-8 I have is version 2.0.3, issued in early 
> 1993.  Is this the latest available version of ProDOS-8?

Yes.

> With my IIgs, my operating system is system 6.0.1.   I assume that this 
> is the latest version; when is the next update likely to be issued?

Yes, it is the latest version.  There has been no update, and it is
very unlikely that there will ever be an update to it (from Apple,
anyway).  Brutal Deluxe claim to have disassembled the system software
and have been working on a set of patches to fix known bugs, but
nothing concrete has surfaced.

Jawaid Bazyar has released a program which patches a bug in the HFS
File System Translator (hopefully making it reliable), based on
information supplied by Dave Lyons.

> I suppose that this may seem to be a dumb question, but can anyone write 
> a version of ProDOS that can access storage devices with more than 32K 
> capacity so that partitions can be larger.....?      

ProDOS uses 16-bit block numbers, and blocks are 512 bytes, so the
absolute maximum size of a volume is 32 megabytes (65536 times 512 =
33554432 bytes).

You cannot change the block size or the maximum number of blocks
without changing the file system and rendering it incompatible with a
lot of existing software.  There is also the minor detail that there is
no memory left in a 64K or 128K machine to be able to add any more code
to the operating system (without breaking more programs).

It might be possible to do more with ProDOS-8 on a IIgs, by moving code
out to other banks, but why bother?  GS/OS does more than any souped-up
GS-only version of ProDOS-8 could achieve.

The best solution to the disk space problem would be a reliable and
faster version of HFS.  This won't help those with 8-bit machines.

Another possibility, given documentation on how to write a GS/OS File
System Translator, would be to come up with a new file system that is
just a bigger version of ProDOS (with some minor improvements to fit
in better with the GS/OS abstract file system).  Any such file system
would be specific to native programs on the IIgs and have no
translation support on other platforms, disk repair utilities, etc.
(unless someone wrote the necessary software), which would severely
limit its usefulness.

It wouldn't be a particularly good file system, unless the underlying
disk space allocation system was changed.  Something like ProDOS is not
efficient on very large volumes.  The techniques used by file systems
like HFS and HPFS (for OS/2) would be a big improvement.

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