Reformatting drives to refresh the format

If this isn't exactly what you wanted, please try our Search (there's a LOT of techy and non-techy stuff here about Linux, Unix, Mac OS X and just computers in general!):

From - Fri Apr  9 15:47:39 1999
Xref: world comp.unix.sco.misc:93748
Newsgroups: comp.unix.sco.misc
Path: world!newsswitch.lcs.mit.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!news.magicnet.net!bilver.magicnet.net!bill
From: bill@bilver.magicnet.netREMOVETHIS (Bill Vermillion)
Subject: Re: How do I low-level-format an IDE Drive?
Organization: W.J.Vermillion - Orlando / Winter Park FL
Message-ID: <F9xI4w.1sFB@bilver.magicnet.netREMOVETHIS> 
References: <370C232C.C1B679EE@mindspring.com> <370C994A.C3D561BC@ilion.nl> 
Date: Fri, 9 Apr 1999 15:38:56 GMT
Lines: 79
X-Mozilla-Status: 8011

In article <370C994A.C3D561BC@ilion.nl>, Tony Earnshaw
<tonye@ilion.nl> wrote:

>Frank Overstreet wrote:

>> ... Now I want to low level format the drive and am wondering
>> if the Western Digital utility wddiag.exe is what I need. When
>> the readme describes writing all 00's is that the same as a
>> low-level-format. If not please help.

>If you even attempt to low-level format a modern IDE disk, you'll ruin
>it. This has long been the case. Writing all 00s is not the same as a
>low-level format, it's what it says.

>Low level formatting was possible, after manufacture, with (now) almost
>prehistoric drives to remagnetize surfaces (thereby removing corruption
>and thus sometimes repairing some bad spots on the surfaces). These
>drives did not carry translation tables, as modern drives do.

The old wives tale of 'remagnetizing' the drives is just a myth.
Magnetic media is quite stable - it's the environment that does
them in re-acting with binders in coated media.  Media for the most
part is plated/sputtered today, so the only problem is the decaying
of the particles.  It just doesn't happen - at least in a computers
lifetime.  This excludes catastophic events of course, and high
heat levels - above 150F you are going to have problems.

One of the ways the myth seemed to get started was on the old MFM
drives of the ST-506 heritage.  These were all 'stepper' drives.
eg - a motor turned x degrees and ratchets the head across the
drive surface.  (In the floppy arena it was typically to have
to re-aline a 5.25" disk every 6 months when used in heavy duty
service.  I did that but was pushing them 24x7x365.  The first
drives would last about a year, and when the 1/2 heights came out
you could expect 4 years approximately - MTBF was about 20,000
hours for those).

The mechanism would wear over time and when the drive was issued
commands to pulse/step the drive to the track, after a time it
the head would not be positioned exactly in the center of the track
set by the original format, and a reformat would then bring back
the performance as first seen as the platter to stepper were now in
sync with the worn portions.

To try to improve performance embedded servos were being used.
This was a servo burst in between sectors.  Doing a real low-level
format meant the drive had to go back to the factor for a new
format and servo.  It was expensive.  Typically the servo looked
like a 'wedge' if you viewed it magnetically as the outer tracks
had the bits spread further apart.

Then came the dedicated servo drive - with the bottom platter
being used only for servo.  This is why you'd see drives
with and even number of platters, but one less than the total
for data.

These are the drives that perform the thermal recal because as the
enivornment changes the metals contract and expand and the bottom
head is controlling the position of all other heads on the stalk.

Current technolgy is embeded servo again - but there's no way a
user can screw these up - as the old drives were controlled by
cards external to the drive, and the new ones are integral to the
units.

This eleminated thermal recallibration, ZBR (zone bit recording)
gives a different number of sectors available on different track
groups.

Low-level reformating really needs never to be done.  Worst case -
to get rid of some pesky droppings by some ill-behaved program, or
programming concept, would be the destructive verify in the
controller.

But 'reformatting to refresh the format' is something left over
from DOS circa 1985.

-- 
Bill Vermillion   bv @ wjv.com 

Take Control of Switching to the Mac

Take Control of VMware Fusion 3

Jump to Comments

Many of the products and books I review are things I purchased for my own use. Some were given to me specifically for the purpose of reviewing them. I resell or can earn commissions from the sale of some of these items. Links within these pages may be affiliate links that pay me for referring you to them. That's mostly insignificant amounts of money; whenever it is not I have made my relationship plain. I also may own stock in companies mentioned here. If you have any question, please do feel free to contact me.

Specific links that take you to pages that allow you to purchase the item I reviewed are very likely to pay me a commission. Many of the books I review were given to me by the publishers specifically for the purpose of writing a review. These gifts and referral fees do not affect my opinions; I often give bad reviews anyway.

We use Google third-party advertising companies to serve ads when you visit our website. These companies may use information (not including your name, address, email address, or telephone number) about your visits to this and other websites in order to provide advertisements about goods and services of interest to you. If you would like more information about this practice and to know your choices about not having this information used by these companies, click here.