From the specs of a hard drive:

# Shock (1/2 sine pulse):

* Operating: 70 G
* Non-operating: 300 G

What does G stand for? Surely not "the force of gravity", as in,
During laundh astronauts are subjected to 10 G" or some number of
them.

On 12/6/2010 8:46 PM, mm wrote:
> From the specs of a hard drive:
>
> # Shock (1/2 sine pulse):
>
> * Operating: 70 G
> * Non-operating: 300 G
>
> What does G stand for? Surely not "the force of gravity", as in,
> During laundh astronauts are subjected to 10 G" or some number of
> them.

Yes indeed, G means the force of Gravity in specs for shock and
vibration.
--
Cheers, Bob

mm <(E-Mail Removed)> wrote:
> From the specs of a hard drive:

> # Shock (1/2 sine pulse):

> * Operating: 70 G
> * Non-operating: 300 G

> What does G stand for? Surely not "the force of gravity", as in,
> During laundh astronauts are subjected to 10 G" or some number of
> them.

Gravity as acceleration (the two are equivalent with the
right frame-transformation). 1G = 9.81m/s^2

Arno

--
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: (E-Mail Removed)
GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

> # Shock (1/2 sine pulse):
>
> * Operating: 70 G
> * Non-operating: 300 G

Physics.

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mm wrote

> From the specs of a hard drive:

> # Shock (1/2 sine pulse):

> * Operating: 70 G
> * Non-operating: 300 G

> What does G stand for? Surely not "the force of gravity", as in,
> During laundh astronauts are subjected to 10 G" or some number of
> them.

Yes, that is what it means.

On Tue, 7 Dec 2010 09:49:55 -0800, "Timothy Daniels"
<(E-Mail Removed)> wrote:

>"mm" inquired:
>> From the specs of a hard drive:
>>
>> # Shock (1/2 sine pulse):
>>
>> * Operating: 70 G
>> * Non-operating: 300 G
>>
>> What does G stand for? Surely not "the force of gravity", as in,
>> During laundh astronauts are subjected to 10 G" or some number
>> of them.
>
> This means that in operation (i.e. with the R/W head over the
>platter), the unit can withstand an acceleration peaking at 70g,
>where "g" is the acceleration of a mass at the earth's surface due to
>gravity, i.e. 32 ft/sec/sec. The graph of the acceleration vs. time
>would be that of 1/2 of a sine wave. In structural mechanics, though,
>the length of time taken for that acceleration to peak (a measure of
>"jerk") would also be significant, and it's not in those specs.
>
>*TimDaniels*

Thanks all.

So they're claiming that the harddrive can withstand a shock of 70
times the acceleration of gravity while the drive is operating without
crashing? Or without failing entirely? Or what?

How would this compare with the shock resistance of a *laptop*
harddrive made in 2000, for example?

On 07/12/2010 1:30 PM, mm wrote:
> Thanks all.
>
> So they're claiming that the harddrive can withstand a shock of 70
> times the acceleration of gravity while the drive is operating without
> crashing? Or without failing entirely? Or what?
>
> How would this compare with the shock resistance of a *laptop*
> harddrive made in 2000, for example?
>

Don't know how it compares to hard drives from ten years ago, but I
think hard drives have been built to similar specs for quite some time
now. They've only been getting bigger and faster, but their physical
dimensions have stayed constant.

The 70 G or 300 G figures would probably correspond to somebody dropping
a running or stopped server from a height of a few feet respectively,
and it coming to a sudden stop on the floor.

Yousuf Khan

mm wrote
> Timothy Daniels <(E-Mail Removed)> wrote
>> mm wrote

>>> From the specs of a hard drive:

>>> # Shock (1/2 sine pulse):

>>> * Operating: 70 G
>>> * Non-operating: 300 G

>>> What does G stand for? Surely not "the force of gravity", as in,
>>> During laundh astronauts are subjected to 10 G" or some number of them.

Yes, but you get much bigger shocks when you drop something onto a hard surface etc.

>> This means that in operation (i.e. with the R/W head over the
>> platter), the unit can withstand an acceleration peaking at 70g,
>> where "g" is the acceleration of a mass at the earth's surface due to
>> gravity, i.e. 32 ft/sec/sec. The graph of the acceleration vs. time
>> would be that of 1/2 of a sine wave. In structural mechanics,
>> though, the length of time taken for that acceleration to peak (a
>> measure of "jerk") would also be significant, and it's not in those
>> specs.

> Thanks all.

> So they're claiming that the harddrive can withstand a shock of 70 times
> the acceleration of gravity while the drive is operating without crashing?

Yes.

> Or without failing entirely?

Without failing at all.

> Or what?

Nope.

> How would this compare with the shock resistance
> of a *laptop* harddrive made in 2000, for example?

It hasnt changed significantly.

Laptop drives have always had significant shock ratings,
because they can see that when put down on tables hard etc.

Mark F wrote
> Rod Speed <(E-Mail Removed)> wrote
>> mm wrote
>>> Timothy Daniels <(E-Mail Removed)> wrote
>>>> mm wrote

>>>>> From the specs of a hard drive:

>>>>> # Shock (1/2 sine pulse):

>>>>> * Operating: 70 G
>>>>> * Non-operating: 300 G

>>>>> What does G stand for? Surely not "the force of gravity", as in,
>>>>> During laundh astronauts are subjected to 10 G" or some number of them.

>> Yes, but you get much bigger shocks when you drop something onto a hard surface etc.

>>>> This means that in operation (i.e. with the R/W head over the
>>>> platter), the unit can withstand an acceleration peaking at 70g,
>>>> where "g" is the acceleration of a mass at the earth's surface due
>>>> to gravity, i.e. 32 ft/sec/sec. The graph of the acceleration vs.
>>>> time would be that of 1/2 of a sine wave. In structural mechanics,
>>>> though, the length of time taken for that acceleration to peak (a
>>>> measure of "jerk") would also be significant, and it's not in those
>>>> specs.

>>> So they're claiming that the harddrive can withstand a shock of 70 times
>>> the acceleration of gravity while the drive is operating without crashing?

>> Yes.

>>> Or without failing entirely?

>> Without failing at all.

>>> Or what?

>> Nope.

>>> How would this compare with the shock resistance
>>> of a *laptop* harddrive made in 2000, for example?

>> It hasnt changed significantly.

> Yes it has.

No it hasnt.

> See, for example:

> http://www.seagate.com/www/en-us/pro...Specifications
> Momentus Laptop Hard Drives with G-Force
> 350G operating, 1000Gs non-operating

It clearly hasnt changed significantly with the drive he quoted the spec of.

> NOTES:
> I think that the ratings on all rotating drives usually means "one time".

You're wrong.

> In other words, the ratings are not "operating" ratings.

How odd that the word operating is used in the specs.

> You'd have to look further into the ratings to see
> what would the rating for an operating environment,
> such as use in a GPS system in a car

That was true of laptops in 2000.

> (although nowadays you'd be using solid memory in a GPS.)

Only a tiny subset ever had rotating hard drives.

>> Laptop drives have always had significant shock ratings,
>> because they can see that when put down on tables hard etc.

Mark F wrote:

>>> In other words, the ratings are not "operating" ratings.

>> How odd that the word operating is used in the specs.

> "operating" means "spinning" in the specs.

Thats the same thing, different words.

> As to how often the shock can be repeated, I rechecked the Seagate
> Barracuda 7200.11 Serial AT Product Manual, publication number
> 100507013, Rev. E (as an example). It seems like the "2.8.5.1
> Operating shock" says no more than 2 times per second and
> "Nonoperating shock" says "nonrepetitive", so I guess I was
> wrong: the operating shock seems to be repeatable many times,
> and just the non-operating shock has a low repeat count (1 total).

Nope, that last just means that it isnt a repetitive shock, not that it can only be done once


>> On Wed, 8 Dec 2010 19:36:23 +1100, in
>> comp.sys.ibm.pc.hardware.storage you wrote:
>
>> Mark F wrote
>>> Rod Speed <(E-Mail Removed)> wrote
>>>> mm wrote
>>>>> Timothy Daniels <(E-Mail Removed)> wrote
>>>>>> mm wrote
>>
>>>>>>> From the specs of a hard drive:
>>
>>>>>>> # Shock (1/2 sine pulse):
>>
>>>>>>> * Operating: 70 G
>>>>>>> * Non-operating: 300 G
>>
>>>>>>> What does G stand for? Surely not "the force of gravity", as
>>>>>>> in, During laundh astronauts are subjected to 10 G" or some
>>>>>>> number of them.
>>
>>>> Yes, but you get much bigger shocks when you drop something onto a
>>>> hard surface etc.
>>
>>>>>> This means that in operation (i.e. with the R/W head over the
>>>>>> platter), the unit can withstand an acceleration peaking at 70g,
>>>>>> where "g" is the acceleration of a mass at the earth's surface
>>>>>> due to gravity, i.e. 32 ft/sec/sec. The graph of the
>>>>>> acceleration vs. time would be that of 1/2 of a sine wave. In
>>>>>> structural mechanics, though, the length of time taken for that
>>>>>> acceleration to peak (a measure of "jerk") would also be
>>>>>> significant, and it's not in those specs.
>>
>>>>> So they're claiming that the harddrive can withstand a shock of
>>>>> 70 times the acceleration of gravity while the drive is operating
>>>>> without crashing?
>>
>>>> Yes.
>>
>>>>> Or without failing entirely?
>>
>>>> Without failing at all.
>>
>>>>> Or what?
>>
>>>> Nope.
>>
>>>>> How would this compare with the shock resistance
>>>>> of a *laptop* harddrive made in 2000, for example?
>>
>>>> It hasnt changed significantly.
>>
>>> Yes it has.
>>
>> No it hasnt.
>>
>>> See, for example:
>>
>>> http://www.seagate.com/www/en-us/pro...Specifications
>>> Momentus Laptop Hard Drives with G-Force
>>> 350G operating, 1000Gs non-operating
>>
>> It clearly hasnt changed significantly with the drive he quoted the
>> spec of.
>>> NOTES:
>>> I think that the ratings on all rotating drives usually means "one
>>> time".
>>
>> You're wrong.
>>
>>> In other words, the ratings are not "operating" ratings.
>>
>> How odd that the word operating is used in the specs.
>>
>>> You'd have to look further into the ratings to see
>>> what would the rating for an operating environment,
>>> such as use in a GPS system in a car
>>
>> That was true of laptops in 2000.
>>
>>> (although nowadays you'd be using solid memory in a GPS.)
>>
>> Only a tiny subset ever had rotating hard drives.
>>
>>>> Laptop drives have always had significant shock ratings,
>>>> because they can see that when put down on tables hard etc.