What are 200G?

[pauloandre]

since noone replied to my other topic (http://forumz.tomshardware.com/hardware/laptop-mp3-player-drive-problem-ftopict190621.html), I decided to change the question a little so see if I got an answer.
Usually laptop hard drives say they can take an shock of 200G while operating. Can someone give me an example of such a force? or even better, if walking fast with a laptop (working, obviously) on a backpack would reach near this limit?

 

[mesarectifier]

The most G force anyone has ever survived is 179.8G (thanks, Wikipedia)

So in short, if your hard drive really does have G tolerance of 200, you'll die before it does.

 

[Sonic_Reducer]

usually a fall will reach those G's and usually hard drives on it's own will support less G tolerance , so that's a nice package, but i don't recomend trying to see when it will break because i think
you'll see parts flying before those 200G's

 

[deweycd]

Yea, 200G is 200 times the force of gravity, a fall causes an impact that can reach up to this much. The sudden decelleration at the ground is able to do this.

 

[13thmonkey]

I'm going to do this in metric, as an example 1g is accelerating by 10m/s in 1 s, i.e. bringing something to a deadstop in 1 sec from 10m/s (or 30ft / sec). In more real terms this is the same at 22mph to 0 in 1 sec.

Therefore from 22mph (10m/s or 30ft/s) down to 0 in 0.5sec is 2G, in 0.05sec is 20G or 0.005sec is 200G.

To decelerate something light in 0.005s from 20mph might not required something too hard, so a hard surface could see you hitting 200G very easily. If it bounces then over a time period it would have seen a larger change in velocity >22mph and may have therefore seen a greater G force.

As you can see by changing the time taken to decelerate an object the G force experienced can be changed. This is how car crumple zones work, they expand the time during which an object is slowed down by allowing the forces to collapse them.

I think that for something like a harddrive to come to a deadstop (exlcuding bouncing) it will take a lot less time than 0.005s, hence even a small drop will be bad news.

If we imagine dropping something, then the height at which it takes 1 sec to reach the floor will mean it is travelling at 10m/s, and if I've done my sums right this should be about a 5m (15ft) height.

The short answer, walking with your laptop should not be a problem, walking into something with your laptop (in a bag) should not be a problem as it will take a long time to slow down, and you are unlikely to travelling at 22mph whilst walking, even with it swinging.

There is a final point, most Gmax measures are taken in 3 axis's i.e. X,Y and Z (left-right, up-downand backward-forward) devices will often be more suseptible to damage in one axis more than another, or X might be 200G, but not Y or Z for instance.

Hope this all helps.

 

[jap0nes]

you sure it is while operating? as far as i know, there are two G forces, one for the drive shut off and other for it operating.
if a drive gets a 200G while operating you'll sure have some badblocks..

 

[MasterLee]

A Top Fuel Dragster leaves the line and there are 6 G's on the driver, and negative 5 to 6 when they pull the chutes. The Space Shuttle does 3G's on the Astronauts during liftoff.
Dropping the drive from about 30 feet to the sidewalk should do it. Let me know if it survives.

 

[pauloandre]

ok maybe I didn't say enough, but I thought everybody knew this... in the specs page it says 200G for 2ms and not repeating more than twice a second. It also says it will not be damaged by a constant vibration of 1G (0-500Hz). I know I'll probably never reach 200G if I'm a little careful, but I might reach the limit of twice a second or the 1G vibration limit. Any thoughts (or real life experiences)?

 

[MrsD]

I know I'll probably never reach 200G if I'm a little careful, but I might reach the limit of twice a second or the 1G vibration limit. Any thoughts (or real life experiences)?

Id recommend not using any type of vibrating device while on your laptop 8O
Also, not when riding a mechanical bull.

 

[rodney_ws]

I'm not professing to be an expert in physics... but I don't think it's fair to compare a falling laptop to a top fuel dragster. The laptop (assuming it hits a solid floor of some sort when its dropped) comes to an immediate stop... it goes from X mph to 0 virtually instantaneously... thus the MUCH higher G force on impact.

I do agree... I can't picture ANYTHING surviving 200 G's... especially when in use. My Dell Inspiron doesn't look prepared to handle a 2 foot drop.

 

[MasterLee]

Just a G example man, and I don't think any hard drive would survive that either.

 

[pauloandre]

I posted the vibration values because I consider walking a vibration (for the laptop in the backpack, that is)