Re: ProDos Disk Images

[jon@i-manila.com (Jon Co)]

I'm not sure exactly which drives are auto inject and which arent, but
way back I had a PowerMac 6100/66 (was borrowed, i have to get it
back) and I remember being able to create,read,write bootable prodos
800k disks in them.  I used macos 8.5 if i remember and diskcopy
images written to disks will read on my IIGS.  Since low density 3.5"
disks are very uncommon now (at least here where i am) I have resorted
to using high density disks with masking tape over the density sense
hole (opposite write protect).  I remember this is how I got GSOS to
initially boot up on my IIGS.
"Bryan Villados" <news002@macgeek.org> wrote in message news:<1U%W9.48559$X7.17503533@twister.socal.rr.com>...
> Maybe I'm wrong at the following assumption...
> 
> Is there a byte-level difference between a ProDOS diskette created on a
> manual-eject drive versues an auto-inject drive? I would think that could be
> the only cause, on a byte/data level. And, with Paul's testing alone, this
> strengthens my assumption. I wish there was some sort of utility that could
> be used to compare diskettes on a track/sector level, comparing a disk made
> with one type of drive, and another made with the other type.
> 
> I'm reading the A2 FAQ, part 6, question #27. Looks to me that for a
> diskette to be bootable, all it needs are certain files to reside on the
> diskette. If I remember my DOS 3.3 correctly, the first few tracks contain
> the bootstrap loader, so the disk could be file-less, but still be bootable.
> Interpreting the FAQ, ProDOS is like the Macintosh OS where the boot files
> could be anywhere on the diskette, and still be bootable. I'm wondering now
> if maybe the placement of the files on the diskette, or the ordering of the
> files themselves in the ProDOS' version of the VTOC (I don't know ka-ka
> about ProDOS inners) could be a factor? A track/sector comparison would show
> these differences. Going along with Paul's theory about the chipset being
> the factor, the outcome of that comparison would be interesting.
> 
> Seeing Paul mentioned the chipset, maybe the chipset does some weird
> ordering of the bytes, or maybe even the operating system itself does this.
> Paul, which version of Mac OS are you running on the 4400? And, what are the
> steps you're using to make the bootable diskette? I have a Power Mac 8600
> myself, but the earliest OS I can run on it is 7.6.1. As a controlled
> experiment, I'm wondering if someone were to try creating a bootable ProDOS
> diskette on a Macintosh running the same OS as your 4400, and native to the
> auto-inject drive. That could help further pin-point whether it's a disk
> chipset, OS version, disk drive, or maybe even a PowerPC vs 680x0 related
> issue.
> 
> --- Bryan
> 
> 
> "Paul Grammens" <grammens@svn.net> wrote in message
> 3e2c6caf@news.svn.net">news:3e2c6caf@news.svn.net...
> > I recently picked up a Mac 4400 with a PC Compatibility card;  it has a
> > 133mhz Wintel PC on a card in addition to a 200 Mhz Power Mac.  I did some
> > experiments to see if I could create bootable ProDos disks. I knew the
> > manual inject floppy was not capable of making a bootable ProDos disk, but
>  I
> > tried anyway. It creates the disk, and can read the disk, but the disk
> > wouldn't work in my IIc +.
> >
> > Next I connected an auto inject floppy from an SE/30. As soon as power was
> > applied, the eject motor came on and stayed on. I found the pinouts for
>  the
> > floppy on the two types Mac, and discovered that pin 9 has +5V on the
>  newer
> > manual eject drives, but is not connected on the auto inject drives.  Pin
>  20
> > has +5V on the older drives, but is not connected on the newer ones. I
> > experimented with that, and found it is not necessary to supply 5V to it
> > because pin 11 supplies 5V.
> >
> > I cut the trace on the floppy drive PC board to isolate that pin, and then
> > found that the drive worked normally in the 4400.  It reads, writes, and
> > formats properly.  So if you want to use an auto inject floppy in a Power
> > Mac, disconnect pin 9. The pins are labeled nicely, and I didn't want to
>  do
> > any cutting on the 4400's cable, so this was the best solution for me.
> >
> > However, I still couldn't make bootable ProDos floppies with the 4400.  I
> > reconnected the floppy to the SE/30 and verified that it could still make
> > bootable floppies there. I also used the same disk image on the SE/30 and
> > 4400, just to eliminate that variable.
> >
> > So the bottom line is that it seems that the floppy controller chip in
>  this
> > Power Mac does not allow even a good ol' auto inject SuperDrive floppy to
> > make usable ProDos disks.
> > -Paul
> >
> >