Re: Unable To Load Prodos

[supertimer@aol.com (Supertimer)]

jonINTERNETrelayCHAT@napaVALLEYnet.CLARInet (Jon Bettencourt) wrote:

>supertimer@aol.com (Supertimer) wrote:
>
>> jonINTERNETrelayCHAT@napaVALLEYnet.CLARInet (Jon Bettencourt) wrote:
>> 
>> >Pim Blokland <nipp@nipp.nl> wrote:
>> >
>> >> jonINTERNETrelayCHAT@napaVALLEYnet.CLARInet (Jon Bettencourt) wrote:
>> >> 
>> >> > > > I know there is a ProDOS file on there, I checked.
>> >> 
>> >> How did you check? Using the same GS?
>> >
>> >On my Mac. I inserted the ProDOS disk and on the root level there was
>> >ProDOS, BASIC.System, System, and Icons. System and Icons were folders.
>> 
>> You created this disk on the Mac, didn't you?  Via DiskCopy, right?
>> 
>> The Mac sometimes has trouble writing ProDOS disks, especially
>> the boot block.  This often renders them unbootable.
>>
>> You have to keep running the archive through DiskCopy until the
>> format "catches."  It might take two or three tries.
>
>Actually, what happens with my computers is kind of interesting. Via
>DiskCopy images, the format never catches, even after more than five
>tries. However, when I format it as ProDOS in the Mac Finder and just copy
>the files, it is able to boot the very first time, or if not the first
>time, the second time.
>
>Could this have been a side-effect of using what the Napa Valley College
>media people said was a Mac drive on a IIgs?

Nope.  If the drive works on the IIGS at all, then it is considered
a IIGS/Mac drive.  Apple designed these to work on both units.

The problem stems from the Macintosh itself.  The Mac's way
of writing disks is not perfect for making ProDOS disks.  The
most sensitive is the boot block, which means that even for
those Mac formatted ProDOS disks that can be read on the
Apple II, they are often not bootable.

PC Exchange, as you've seen, handles it a little better than
DiskCopy sometimes, but it too is not perfect.

However, the IIGS reads and writes Mac 800k HFS disks
(and HFS hard drive and Zip disk partitions) with ease.  IIGS
writing Mac disks ALWAYS works while the reverse is not
true.

If all else fails, get the disk via .shk archives or as real disks
and then use the IIGS' ability to read Mac HFS disks to
transfer files later on.