Re: System disks for Apple //gs or Localtalk boot?

["Roger Johnstone" <rojaws@es.co.nz>]

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In article
<processoroverclocked-0707001510160001@dialup-napanet-206-81-101-250.napanet
.net>, processoroverclocked@33mhz.cjb.net (Jon Bettencourt) wrote:


>In article <20000707020707.02245.00001828@ng-bh1.aol.com>,
>nchaimov@aol.com (Nchaimov) wrote:
>
>> Actually, any mac with a SuperDrive *can* make a bootable ProDOS disk, it's
>> just that the MacOS doesn't write the requisite boot blocks to the disk when
>> it's formatted.
>
>Actually, sometimes it does and sometimes it doesn't. It all depends on
>what machine you have and what method you use to format the disk.
>Sometimes the result is a little unpredictable.
>
>I'm going to start building a list of what works and what doesn't.
>
>PowerMac 7100/66 @ 88MHz
>   DiskCopy: fails
>   Mac Finder: succeeds
>
>Tammy and TIA,
>----> Jon.

There seem to be two problems here, one with Disk Copy and the other with
the drives used in later Macs. Apple has a tech note at
http://til.info.apple.com/techinfo.nsf/artnum/n30959 which mentions problems
with the manual inject drives used in later Macs, when formatting Apple II
disks.

There is also a problem with Disk Copy, at least on my iMac running Mac OS
8.1. The iMacs don't have a floppy drive, but they do have all the hardware
required to add one. I installed a D19 socket on the side of my iMac so I
can plug in my IIgs 800KB drive, it works perfectly for Apple II or Mac
800KB disks.

I did some experimenting today and found disks formatted from the Mac Finder
and with the files copied onto it boot on the IIgs, but the same disk
created with Disk Copy failed to boot past the *** UNABLE TO LOAD PRODOS ***
stage, neither could the disk be cataloged (I/O error). Checking the disk
with a verify program on the IIgs, it seems that every block gets an I/O
error _except_ the boot block! 

(n.b.: remember that if you get the 'unable to load ProDOS' message it means
that the disk did start to boot, since this message is an error reported by
the program stored in the boot block itself, but the boot code could not
find the ProDOS file on the disk, which will be the case if the rest of the
disk can't be read)

I put the drive back on the iMac and found that the Mac Finder could read
the disk fine. I could even get Bernie to boot from it. The disk was also
checked on a PowerBook 5300 and worked fine. The same disk created with Disk
Copy on the PowerBook booted and ran on the IIgs.

The problem with Disk Copy on my iMac is not the disk drive (real Apple II
drive!) or the OS version (8.1, same as the PowerBook) or the version of
Disk Copy (latest 6.3.3 or older 4.2 produce same results). The only other
thing I can think of is an incompatibilty between the iMac hardware and Disk
Copy which causes the disks to be written in some funny format which a Mac
can still read but an Apple II can't.

iMac 233 (Bondi rev A) @ 266MHz
    DiskCopy: fails
    Mac Finder: succeeds

PowerBook 5300c
    DiskCopy: succeeds
    Mac Finder: succeeds

Roger Johnstone, Invercargill, New Zealand
http://homepages.ihug.co.nz/~rojaws
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Software isn't released, it's allowed to escape.