Path: utzoo!utgpu!water!watmath!clyde!rutgers!mit-eddie!bu-cs!madd
From: madd@bu-cs.BU.EDU (Jim Frost)
Newsgroups: comp.sys.ibm.pc
Subject: Re: RESET BUTTONS AND HARD DISKS
Message-ID: <19370@bu-cs.BU.EDU>
Date: 27 Jan 88 21:40:45 GMT
References: <3505@batcomputer.tn.cornell.edu>
Reply-To: madd@bu-it.bu.edu (Jim Frost)
Followup-To: comp.sys.ibm.pc
Distribution: comp.sys.ibm.pc
Organization: Boston University Distributed Systems Group
Lines: 44

In article <3505@batcomputer.tn.cornell.edu> dorin@tcgould.tn.cornell.edu (Stewart Johnson) writes:
>I am told that a hardware reset button is a good idea if one has a hard 
>disk. Why? 

Spinning up and down the hard disk shouldn't really be done all the
time.  A reset switch allows you to reset the processor without
powering down the whole system.  This saves wear and tear on the
drive.  (There can also be head considerations but this isn't
universal.)

>I always park the heads before turning the machine off. What is the danger
>of not doing so?

A lot of fear over parking the heads has to do with real old drives.
I had the (mis)fortune of being around once when someone powered down
an external drive attached to an old Rainbow without performing normal
shutdown procedures.  The heads slammed into the disk and made this
interesting noise that I'd appreciate never hearing again.

New drives don't usually exhibit this type of behavior.  A power down
isn't really good for the drive, but doesn't usually hurt anything.
If you fail to park the heads, they may be sitting over (on?) your
actual disk surface.  If the PC is moved around, it is possible to
damage the surface of the disk and therefore the data.  This is why
nearly every disk manufacturer recommends parking the disk before
moving your PC but very few recommend parking every time you turn off
the computer.  Usually it's only a problem if you're moving the thing.

Many new disks have automatic parking; when the power fails, the heads
retract to a "safe" place automatically.  You don't need a program to
do it for you.  Most of the 20-40Mb disks DO NOT do this, but quite a
few 70+Mb disks do.  Almost all disks that have this feature have it
documented somewhere (although I've seen disks that I know to be
self-parking come without any indication of this ability).

I almost never park the disk on PCs that I use because they're not
going to be moved.  But then again, I back them up all the time so it
really doesn't matter to me that much.  If you're worried about your
data, you should probably park it.  If you have any doubts about it,
just remember that it doesn't hurt anything to park the drive, it just
takes a little more time.

jim frost
madd@bu-it.bu.edu