🚀 go-pugleaf

In article <GINSBURG.91Jun19164100@rio.cme.nist.gov>, ginsburg@cme.nist.gov (Dylan Ginsburg) writes:
|> In article <1991Jun19.145110.31553@kuhub.cc.ukans.edu> 1h1a0m@kuhub.cc.ukans.edu writes:
|> >   I did low level format the HD upon the recommendation of tech support at
|> >   HDI (Hard Drives International).  They said low level formatting should be
|> >   done every 6 months or so.  It didn't hurt my HD since I knew what I was
|> >   doing.
|> >
|> >   I guess we could close the thread on this topic for now.
|> 
|> Not quite, why should the drive be low level formatted every 6 months?
|> 
|> -Dylan

Actually it depends on the type of disk drive you have...regular low level formatting
*is/was* recommended for the disk drives with stepper motor head acuators (mostly older
drives and current low end drives). This applies primarily to MFM and RLL drives (not sure
about IDE drives since you generally *can't* low-level format them, SCSI & ESDI I have
no experience with). The reason being is that stepper motors position R/W heads relative to 
themselves, NOT relative to the disk surfaces (basically it sticks the heads in a particular
position in space and *hope* that the particular track is under it). The position of the
r/w head relative to a given track *can* change over time due to wear, thermal expansion,
mounting position (vertical/horizontal/upside-down...) bumps & shocks, (the phase of the
moon :-). The relative positioning can drift somewhat without any problems, but if it
drifts too much, you begin to get problems such as overwriting old data on adjacent tracks,
not being able to read sector information (laid down during a low-level format). Generally
this manifests itself a rash of disk I/O errors, sectors not found, bad blocks, etc...
Low-level formatting basically re-aligns the r/w heads with the tracks by erasing the old
tracks and placing new tracks directly under the r/w heads...

Thats a very general description of why the recommendation...as I said this applies to
RLL & MFM disks, I don't have any experience with IDE/ESDI/SCSI drives...


John


+--------------------------------------------------------------------+
| John Burton                                                        |
| G & A Technical Software                                           |
| jcburt@gatsibm.larc.nasa.gov                                       |
| jcburt@cs.wm.edu                                                   |
|                                                                    |
| Disclaimer: Hey, what can I say...These are *my* views, not those  |
|             of anyone else, be they employer, school, or government|
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