[aus.computers] Amiga 3 1/2" Media Problems

jon@runx.ips.oz (Jonathon Seymour) (08/06/88)

A problem with a well-used 3 1/2" AMIGA disk
--------------------------------------------

Has any one experienced wear problems with 3 1/2" disks? Today I discovered
that my boot disk has had tracks 0->3 on side 0 irrecoverably damaged - I
can't read any sector from any one of those 4 tracks and cannot reformat
the tracks. On checking the disk physically I found that the outer few
tracks on the top side of the disk possessed a dull surface as opposed to
relatively shiny surface which characterises the rest of the disk.  By
comparing this surface with the other side of the disk and other less
frequently used disks I concluded that the difference in surface quality is
due to wear. 

I don't know enough about the physical layer of the disk format to know how
much of the track has to be damaged to make the whole track unreadable. Can
anyone enlighten me?

Other aspects of the situation intrigue me:

	Could all four tracks have been damaged simultaneously, and how?

	Why only those four tracks? Track 0, I assume, is accessed rather
	regularly. But why did tracks 1->3 go and not tracks 4, 5, etc.?

As well as *answers* to these questions I would be interested to hear if
anyone else has had any problems that they think are related to wear, how
frequently these problems occur, and under what circumstances.

Finally, can anyone recommend a disk head cleaning kit for 3 1/2" disks.
(Australian distributors only please).

Replies by mail please(unless from OS). I'll summarise any replies that may
be of a more general interest. 

jon. 

'Einstein was right: 
	"God doesn't play dice with The Universe". 

The truth, of course, is that it is The Universe that plays God with dice.'