Re: Can't read directory with //c internal floppy drive

[voss@i40s16.ira.uka.de (Stefan Voss)]

In article <TIM.93Dec15203419@lantra.harlequin.com>, tim@harlequin.com (Tim McNerney) writes:
|> I recently bought a //c which seems to mostly work.  I have successfully
|> booted Terrapin Logo, AppleWorks, VisiCalc, and the Pinball Contruction
|> Set.  AppleWorks seems to have no problems displaying a list of files on
|> one of its disks, but Logo ("CATALOG") and VisiCalc ("/SL") can't read the
|> directory from any disk.  I took the cover off the //c and the floppy drive
|> to see what was going on, and this is what happens:  The stepper motor
|> pulls the head all the way out to the edge of the disk, then it makes a
|> loud buzzing noise (a cross between a "braaaap" and "ra ta ta ta tat"),
|> then it complains of a DISK I/O ERROR.

I suppose that the source of the problem are the floppies, not the drive. 
The head move to the outer edge of the disks probably occurs because a ProDOS-based
program wants to access the root directory which is placed at blocks 2-5 
(at track 0). When a DOS3.3-based program reads a directory, the read/write head
is moved to track $11 (one of the tracks in the middle). 
Did you check the disks for bad blocks? (With a disk utility like ProSel-8
or Copy II+)

Another point: 
You are not trying to read a ProDOS disk from a DOS3.3 program or vice versa, 
are you? This won't work. I mention this because I remember VisiCalc being
a DOS3.3 program (long time ago), but you want to access a ProDOS directory ("/SL"). 

|> 
|> I believe that this //c is a relatively early model, no superdrive or
|> anything of the sort, just a plain vanilla 5 1/4" single sided drive.

I own a //c since 1985. I never had any problems with it.

|> 
|> [stuff deleted]
|> 
|> --Tim

Stefan Voss
(voss@ira.uka.de)