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FastMHz

Hard Drive Linear Velocities...

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Math isn't my strong suit, but I got curious and ran some calculations. I wanted to know if the linear velocity under the heads of my velociraptor compared to my previous 7200 rpm disk, given the smaller platter diameter. I found interesting correlations...that is, if my numbers are right :-P

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I wanted to know if the linear velocity under the heads of my velociraptor compared to my previous 7200 rpm disk, given the smaller platter diameter.

That's seems right. I recently did some similar calculations: a 3.5 inch hard disk running at 7,200 rpm could theoretically offer slightly faster linear velocities than a 2.5 inch disk running @ 10,000 rpm, given the same density (bpi).

I don't know where to find dpi and tpi values for the new Velociraptor or e.g. the new Seagate 7,200 rpm disk with 1 TB platters, but bits per inch should be almost the same, because the max. transfer rates are about the same.

Edited by uhs

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Yeah, it's interesting that a 2.5 @ 10k is about the same as a 3.5 @ 7.2k, and a 2.5 @ 7.2k is the same as a 3.5 @ 5.4k.

I got a new Velociraptor the other day to replace a 7200 3.5". The data density must be better because the Velociraptor whoops the 3.5 in streaming as well as random access. Actually the VR totally owns the 3.5 for random access, which is why I did the upgrade.

As a side note, I finally have my ultimate setup going now:

SSD for OS/Apps

150g Velociraptor for Swap/Temp

300g Velociraptor for small data (documents, pics, firefox user profile, etc)

1TB 5400rpm Samsung for medium data (ISOs, Ghost images, etc)

14TB homebrew NAS for audio/video

Edited by FastMHz

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I have 16GB of RAM, so swapping is rare. But if it does start swapping, like if I'm running a few VirtualBoxes or something, I don't want all those writes cooking up an SSD for dinner :-) The VR does very very well in this role. I also use the swap drive as a scratch disk for photoshop, media encoding, etc. It's main purpose is to absorb the high volumes of writes I generate daily.

I would have bought more RAM and bypass the swap file...

MEJV

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