"The Inner World of the Hard Drive" (chuckle)

[iGary]

Here's one for the abecedarians out there:

• ...a point close to the outer track is moving at roughly 48 miles per hour.
  
  ...But that's not the most amazing part. Each hard drive consists of one or more platters, called the substrate...

http://www.extremetech.com/article2/0,1558,1777124,00.asp

 

[Buck]

How did they come up with 48-miles per hour?

 

[Mercutio]

Well, there was probably some math involved...

 

[Buck]

Well, there was probably some math involved...

Yeah, the funky kind, like 1+1=3.

 

[Splash]

How did they come up with 48-miles per hour?

I don't know. I do recall from doing a shirt sleeve calculation years ago that the outer edge of a 15kRPM hard drive platter is zipping along at well over 100 miles per hour (160+ KPH) and that the outer edge of a mundane 7.2kRPM hard drive platter is zipping along at about 100 KPH (60+ MPH).

Maybe his notebook computer's hard drive is going at 45 MPH -- probably spinning backwards also.

 

[LunarMist]

I thought a 7200 rpm drive was around 75 mph. Anyway, it really doesn't matter, the article is just silly.

 

[LunarMist]

OK. Assuming 3' platters, the edge of a 7200 rpm drive is moving at 64 mph. The edge of a similar 5400 rpm drive would be - you guessed it - 48 mpg. I wonder at the age of the source material for that article.