OS-9/68k v2.3/2.4 RBF question - 0-based sector patch?

[usenetsp...@gmail.com]

Hi all,

A while ago I managed, though sheer luck, to obtain the Cumana/Recc-O-
Ware OS-9/68k v2.3 port for the Atari ST. I've imaged the disks just
in case they go bad, via Kermit and via Bob van der Poel's Linux
scripts. The distro disks were /u0 format (80 track, 16 sectors,
256bytes/sector).

I'd like to run OS-9/68k with STeem, the Atari ST emulator, but it
can't emulate the disk controller properly when software tries to read/
write sectors numbered starting from 0. In fact, it's pretty darn hard
to read these formats on ANY modern system, and basically impossible
to write them back to real floppies using Linux or Windows, so far as
I can tell.

I know that with the 'dmode' util I could define 512-byte sectors, but
I'm not sure how to force sectors to start at 1, which is the main
stumbling block for easy portability to other systems, and to
emulation.

Is RBF hardcoded to number sectors starting at zero? If so, does
anyone know of a patch to format sectors from 1 instead?

Thanks,
-Russ

[Martin Whitaker]

You can use the "sector base offset" field in the device descriptor. The
Cumana/reccoware device driver does pay attention to this field - I used
pcf to read/write DOS formatted floppies when I was running OS-9 on my ST,
and that required sectors to be numbered from 1.

However, I think you'll need access to a working OS-9 system to create the
new device descriptor and new floppies in that format...

Martin

[usenetsp...@gmail.com]

On Jan 13, 1:30 pm, Martin Whitaker <spamt...@martin-whitaker.me.uk>
wrote:

I do have another OS-9/68k system so I can probably do that. I just
wanted to be sure it was actually possible :)
It didn't occur to me that PCF would indeed require the
sector_base_offset parameter to read/write DOS disks, good point.

Since you've actually used the recc-o-ware port, do you know if it
boots properly on Atari TT using the 68030 kernel? I saw the option in
the installation but haven't yet tried it.

Thanks very much.
-Russ

[Martin Whitaker]

usenetsp...@gmail.com wrote:
> I do have another OS-9/68k system so I can probably do that. I just
> wanted to be sure it was actually possible :)
> It didn't occur to me that PCF would indeed require the
> sector_base_offset parameter to read/write DOS disks, good point.
>

Having dug out my Cumana stuff, I notice in the release notes (OSK
V2.3/Reccoware V1.30) that they added device descriptors for the
"universal" floppy format (DSDD, 80 tracks, 16 sectors per track, sector
offset 1, track offset 1). If you have the same release, look for a device
descriptor named d0u.<step-rate>.<track-size>.

It occurs to me that there may be another stumbling block. IIRC, OS-9 was
started by running a bootstrap program. That program may not recognise
floppies in a different format. But I think the source code was supplied
for that program, so this may be surmountable.

> Since you've actually used the recc-o-ware port, do you know if it
> boots properly on Atari TT using the 68030 kernel? I saw the option in
> the installation but haven't yet tried it.
>

No, it didn't work on the TT - the hardware is too different. IIRC, the
68030 kernel option was for an accelerator card wired into a standard ST.

I ran it on a MegaSTe. This was mostly successful, although I had to patch
the hard disk driver because it contained a timing loop that ran too
quickly when operating at 16MHz. Even then, it hung occasionally, which
made me suspect there was another timing problem in the driver.

Let me know if you have any success - I'm tempted to dig out my disks and
indulge in a bit of nostalgia.

Martin

[usenetsp...@gmail.com]

On Jan 14, 12:57 pm, Martin Whitaker <spamt...@martin-whitaker.me.uk>
wrote:

Cool, it's nice to at last find someone who knows a bit about this
particular port of OS-9!

The same issue did occur to me yesterday as I was starting to look at
the descriptors.
I do have an OS-9/68k port pack dev kit that I inherited from a
previous employer, many years ago -- it's for OS-9 version 3.0, and I
used to do a lot of Atari ST programming so I could almost certainly
write a new bootloader for 512-byte sector floppies using sector 1
base offset if the existing Cumana loader doesn't work.

Thanks for the help; I'll post here in a few days with the results of
my experiments.. since my other OS-9 boxes use 2.4 and 3.0, I'm going
to try upgrading the ST port as well.