[comp.sys.ibm.pc] A question about hard disk

meric@portia.Stanford.EDU (meric ozcan) (12/20/89)

I have a 60 Mbytes Seagate hard disk (ST-277R-1, RLL type) with autopark
feature. When the power is turned off there is some strange sound coming
from the hard disk and it lasts about 5 seconds. It is not the whining
sound  from the motor. I have never heard this kind of sound from any
other hard disk. I will try to describe the sound:
	After you turn off a fan, while it is spinning if you put a stick
between the fan blades you would get a similar sound. 
I am really curious about this. Does anyone have any idea?   Thanks.

sigma@pawl.rpi.edu (Kevin J Martin) (12/21/89)

In article <7799@portia.Stanford.EDU> meric@portia.Stanford.EDU (meric ozcan) writes:
>
>I have a 60 Mbytes Seagate hard disk (ST-277R-1, RLL type) with autopark
>feature. When the power is turned off there is some strange sound coming
>from the hard disk and it lasts about 5 seconds. It is not the whining
>sound  from the motor. I have never heard this kind of sound from any
>other hard disk. I will try to describe the sound:
>	After you turn off a fan, while it is spinning if you put a stick
>between the fan blades you would get a similar sound. 
>I am really curious about this. Does anyone have any idea?   Thanks.

I have the same half-height hard drive sitting right here, and yes, it
makes the exact same noise.  I had always assumed it was the autopark
feature; it seems to last longer sometimes, as if perhaps the heads
have to move further.  I don't know enough about the mechanics of hard
drives to be sure.  I've heard similar sounds from other drives, but this
one is admittedly louder than most.  But nothing to worry about.

-- 
Kevin Martin
sigma@pawl.rpi.edu
(Just because I'm paranoid doesn't mean 
 the whole world isn't out to get me)

davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) (12/21/89)

  I'm told that the sound is the momentum of the platters being used to
rachet the head back to safe parking. You should notice that the sound
changes depending on what program you ran before shutdown. Nothing to
worry about, they all do it, many with a distinct CLICK at the end of
the sound.
-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"The world is filled with fools. They blindly follow their so-called
'reason' in the face of the church and common sense. Any fool can see
that the world is flat!" - anon

poffen@molehill (Russ Poffenberger) (12/22/89)

In article <7799@portia.Stanford.EDU> meric@portia.Stanford.EDU (meric ozcan) writes:
>
>I have a 60 Mbytes Seagate hard disk (ST-277R-1, RLL type) with autopark
>feature. When the power is turned off there is some strange sound coming
>from the hard disk and it lasts about 5 seconds. It is not the whining
>sound  from the motor. I have never heard this kind of sound from any
>other hard disk. I will try to describe the sound:
>	After you turn off a fan, while it is spinning if you put a stick
>between the fan blades you would get a similar sound. 
>I am really curious about this. Does anyone have any idea?   Thanks.


Ny st251 also does this. I presume the autoparking mechanism uses disk
momentum in a mechanical operation of some kind to park the heads. The noise
is that mechanical action.

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
Schlumberger Technologies       UUCP:   {uunet,decwrl,amdahl}!sjsca4!poffen
1601 Technology Drive		CIS:	72401,276
San Jose, Ca. 95110
(408)437-5254

ppa@hpldola.HP.COM (Paul P. Austgen) (12/22/89)

Mine has been doing this for two years and it works just fine.
My opinion (not verified) is that this is the spindle grounding
tab that bears on the spindle.

karl@ddsw1.MCS.COM (Karl Denninger) (12/25/89)

>Item 7673 (0 resps) by meric at portia.Stanford.EDU on Sun 24 Dec 89 18:32
>[meric ozcan]    Subject: A question about hard disk
>(8 lines)
>
>
>I have a 60 Mbytes Seagate hard disk (ST-277R-1, RLL type) with autopark
>feature. When the power is turned off there is some strange sound coming
>from the hard disk and it lasts about 5 seconds. It is not the whining
>sound  from the motor. I have never heard this kind of sound from any
>other hard disk. I will try to describe the sound:
>	After you turn off a fan, while it is spinning if you put a stick
>between the fan blades you would get a similar sound. 
>I am really curious about this. Does anyone have any idea?   Thanks.

Yes, it's normal.  It is the heads autoparking.

The drive stores a small amount of power (actually, I believe it is using
regenerative power from the drive motor!) and uses that to park the heads. 
It does this by continually stepping the heads towards the park position. 
Since the platters are spinning when you powerdown, the motor beocmes a
generator.... and provides the power for this.

You may have noticed that the sound slows down and becomes softer as the
motor stops spinning.... because the generator is running out of steam! :-)

--
Karl Denninger (karl@ddsw1.MCS.COM, <well-connected>!ddsw1!karl)
Public Access Data Line: [+1 708 566-8911], Voice: [+1 708 566-8910]
Macro Computer Solutions, Inc.  "Quality Solutions at a Fair Price"

O04@PSUVM.BITNET (Kevin Maher - Behrend Computer Center) (12/27/89)

The sound from the drive is simply the autopark mechanism.  I have an
ST-251 (which is what the ST277R really is) that has this feature.
It is perfectly normal, and unless it starts to sound radically different,
you dont have to worry about it.

PS: It can get annoying though!

akcs.amparsonjr@vpnet.UUCP (Anthony M. Parson, Jr.) (01/06/90)

Now I know what that ST-251-1 sound is! (It never bothered me, tho).  I
use a "park" program to part the 251-1 and the 225 (still no bad sectors
after almost 4 years)

Now, similar to the sound of a 251 being autoparked:  My 1971 Maverick,
when I take my foot off the gas at, say, 55 miles an hour, does a similar
thing, which stops if I give it gas.  Tires/wheels are only bubble-
balanced, which might explain it, but the old tires did the same thing;
Short of getting the wheels balanced while they are on the car (to take into
account the brake drums and wheel weights), why doesn't the noise occur
at a constant 55 miles per hour?    
[I am also used to this noise, but the 251 discussion reminded me]

tcm@srhqla.SR.COM (Tim Meighan) (01/13/90)

In article <25a4d323:3746.6comp.sys.ibm.pc;1@vpnet.UUCP>
akcs.amparsonjr@vpnet.UUCP (Anthony M. Parson, Jr.) writes:

>Now, similar to the sound of a 251 being autoparked:  My 1971 Maverick,
>when I take my foot off the gas at, say, 55 miles an hour, does a similar
>thing, which stops if I give it gas.

This is, without a doubt, the most amazing digression of a topic I have
ever seen in this newsgroup!

Tim Meighan
Silent Radio