Re: Help with GS and Mac

["Roger Johnstone" <rojaws@mac.com>]

All Macs with a built-in floppy drive support 800KB disks. Mac OS X doesn't
support ANY built-in floppy drives (yet, possibly ever), but earlier
versions of the OS work fine with 800KB disks.

I posted the following here previously in a discussion about problems
creating Apple II disks on a Mac:

> 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.


--
Roger Johnstone, Invercargill, New Zealand

Apple II - Future Cop:LAPD - iMac Game Wizard - WarCraft II
http://homepage.mac.com/rojaws
___________________________________________________________

"I think there is a world market for about five computers."
    Remark attributed to Thomas J. Watson
    (Chairman of the Board of IBM), 1943