🚀 go-pugleaf

In article skipm@dorsai.com (Dorsai SysOp) writes:
>s64421@zeus.usq.EDU.AU (house ron) writes:
>> I have a Connor 80Mb drive...which came with a big sign saying
>> not to ever run any parking software, as the drive parked automatically
>> and would be damaged by the software.
>I doubt this holds any validity. I will say that some parking software...
>I know, do auto-park on power failure. Western Digital IDE's however,
>do not.

   I don't know connor's problem, but I have fixed drives where this was done.
BACKGROUND: Drive parking can be done at several points in several manners.
The controller can (be mfg'ed) sense power failure and issue a park command,
or the drive interface can do the same thing.  A park command can be done
several ways,last cyl figured and seek commmand issued, first cyl seek
command issued, or most commonly a seek_HI_# command issued.  In this case,
knowing that the drive is dowing down, and time is a issue, a out_of_range
seek is issued to get the drive done ASAP.  When this is done twice, the
heads can be jammed against the inside hub rail, killing the drive.  Using the
original IBM AT 20 MB CDC disk with a Western Digital controller caused this
problem all the time, as the western digital was designed with a park address
high, and the drive with park at 0. Further the drive had like zero overrun
at the high end, and they jammed up.
   This is what I suspect is what the warning was due to.  IF they do actually
get stuck, you can open the drive and release it by hand. Although I don't
recommend opening up a drive like that, the choice is yours.  (Obviously,
I've done it, but...)
al



-- 
Al. Michielsen, Mechanical & Aerospace Engineering, Syracuse University
 InterNet: amichiel@rodan.acs.syr.edu  amichiel@sunrise.acs.syr.edu
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