Tools : copied from the Scottish Landrover Owners Club website

On or around Sun, 25 Sep 2005 19:56:51 +0100 (BST), "Dave Liquorice" enlightened us thusly:

all the discs have a maximum safe speed marked on 'em. For little ones this is usually about 12500, but 9" for example are mostly about 7000 I think, and 12" slower than that. 's about the angular velocity of the periphery, I assume.

's like the urban myth about 56x CD drives - it was alleged that the periphery of the disc goes supersonic, thereby shattering it. not true. But they might still break up due to centripetal forces. ISTR that "standard" CD speed is 300 rpm, so a 40x one is doing 12,000 flat out.

CDs are constant linear velocity so the RPM varies on where on the disc you are reading data. Quick google looks like the linear speed is

1.2 to 1.4 m/s or around 200 to 500rpm. It does appear that CDs can fail at high speeds but that is because they ain't strong enough not because of supersonic edges. 1.4 * 56 = 78.4m/s or 175mph way short of supersonic at around 750mph...

Modern data drives are not CLV though as spining a disc up and down from 2,000 to 12,000+ RPM isn't easy. They are Constant Angular Velocity and the drive sorts out the varying data rates depending on what bit of the disc is being read.

On or around Tue, 27 Sep 2005 11:01:33 +0100 (BST), "Dave Liquorice" enlightened us thusly:

quite. nowhere near. Mind, I gather they can indeed fail, which must be quite impressive.

On Tue, 27 Sep 2005 09:52:09 +1200, EMB scribbled the following nonsense:

What are you saying about the wonderful Charlotte..... Martyn may correct me, but last application of WARREN and CHEQUE BOOK was for her (and Max's) benefit!

Doesn't the "40x" refer to theoretical data rates rather than rpm?

I can't remember the figures, but the "40x" is a marketing dept. abuse of the facts anyway.........

Richard

On or around Tue, 27 Sep 2005 15:55:18 +0000 (UTC), beamendsltd enlightened us thusly:

highly probable. I've not yet worked out which of intel and AMD are extracting the urine about processor speeds, probably both.

Processor speed is pretty meaningless - unless you are comparing two processors of the same design.

Richard

I wouldn't describe Charlotte as "background", nor as a "service"! Not within right-hook range anyhow.

It wasn't directed at Charlotte - more a general stating of what I have seen wives do after the spending of vast sums on 4WDs.

Oh yes