Re: IIc Questions

[a_specto@alcor.concordia.ca (Mitchell Spector)]

Robert Boucher <rboucher@houston.rr.com> wrote:

>I pulled my old IIc out of storage to run an application that was on a 5
>1/4" disk. I got a Could Not Load ProDos message on this disk, an
>Appleworks install disk and the ProDos Users Disk. From this little
>info, can anyone tell if the internal disk drive is bad, or just needing

    You normally get the "UNABLE TO LOAD PRODOS" message if
there is no executable program or system file in the root directory of
a ProDOS formatted device (i.e. "PRODOS", "BASIC.SYSTEM" or
anything with a *.SYS/*.SYSTEM extension in the name or filetype). 
You _must_ have the "PRODOS" system OS file in the root directory.
 
    It's possible such files on your disks were inadvertently renamed
and not being found, or the diskettes themselves are corrupted or
damaged. The fact that your getting that error message means it's
at least reading the boot sector, so I'd tend to doubt it's faulty
hardware.

>cleaning? If the internal drive is bad, can I boot from an external 5
>1/4" drive?

    The original IIc firmware (ROM '255') allowed you to boot from an
external 5.25 drive by typing "PR#7" at the Applesoft prompt. Later
ROM versions changed this, and I can't quite recall off hand if there
was an alternate way to do this (rudimentary hooks for an external
AppleTalk device lived in slot-7 in the next ROM, and then the mouse
firmware was mapped there in the following two ROM revisions).

>Also, I think I remember the IIc needed a "special" 3 1/2". Is this
>correct, and if so, what is the drive's designation?

    Correct, the only compatible 3.5 drive was the Apple UniDisk 3.5
(it was an "intelligent" device with its own ROM, RAM and CPU).
You can easily spot one as it was snow-white in color, matching the
IIc's unique color scheme, and had the LED and eject button raised
just above the front disk slot. Of course the product sticker under-
neath clearly identified it as well.

    The UniDisk 3.5 operates at roughly half the speed of a standard
3.5 drive, but in the case of the IIc it's your only option (the IIc+
model is a different story). They're on the rare side, I'd imagine
more so today than several years back.

Mitchell Spector
a_specto@alcor.concordia.ca