the beginning of the end for floppies

Chuck Guzis cclist at sydex.com
Thu Apr 29 02:41:18 CDT 2010


On 29 Apr 2010 at 9:11, Jochen Kunz wrote:

> 8" flppies where already gone and replaced by 5.25", when I got my
> fingers on a computer for the first time. -- 

8" floppies are quite reliable.  I routinely get 30+ year old disks 
in and rarely have a problem with data errors.

Although I do have an odd case before me.  The subject floppies are 
from a Schlumberger wafer tester.  What was sent were hard-sector (32 
sector) floppies, but the data is definitely soft-sector (i.e. the 
sectors don't line up with the sector holes and use address marks 
(i.e. A1 with a missing clock)  to demarcate sector headers and 
sector data.)  My guess is that the drive was set up to handle hard 
sectored media., so that the controller still sees only one index 
pulse.

The sector address headers, rather than use  CHRN type information, 
use 2 bytes to number the sectors on the disk consecutively.

The odd thing is that on a few floppies, the data (and address 
headers) is in the wrong place for that cylinder (e.g., track 3 
contains the same address headers and data as track 9).  I'm trying 
to figure out if it's the customer's drive or his software (he's 
halfway around the world from me).

Very strange.

--Chuck




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