Re: My laser 128

[Michael J. Mahon <mjmahon@aol.com>]

D Finnigan <dog_cow@macgui.com> wrote:
> Michael J. Mahon wrote:
>> Antoine Vignau wrote:
>>> 
>>> For my knowledge, from where did you get that information, Michael?
>> 
>> I don't have a specific reference--that was just from memory.
>> 
>> I just checked a couple of places I might have read it, but came
>> up empty.  In fact, I haven't found any specific information on
>> the ProDOS Filer formatting algorithm.
>> 
> 
> I too checked my Apple documentation last evening. I examined the following
> volumes:
> 
> - ProDOS User's Manual (an entirely useless manual!)
> - BASIC Programing with ProDOS
> - ProDOS Technical Reference Manual
> 
> All three did not say anything about detecting bad blocks. But I wasn't
> reading an Apple manual, so maybe the other of the 3rd-party publication
> just made an assumption.
> 
> Interestingly enough, the ProDOS User's Manual alludes to the fact that
> formatting a disk helps with bad blocks.
> 
> It suggests (slightly paraphrased):
> 
> "If you find a disk that has bad blocks by using the Detect Bad Blocks
> feature, you should immediately copy all files from that disk to a new disk,
> then format the old disk."

That's because reformatting a floppy will recreate the address marks, which
could be the reason that blocks are bad. 

-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon