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Why does data transfer rate go down during Benchmark test?

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Anonymous
a b G Storage
August 8, 2005 7:47:46 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Hi!~

I'm testing Hard Disk performance with WinBench 99 Ver2.0.

In the results, I wonder about Data Transfer Rate test.

Data Transfer Rate result was represented graphically like curbe line
of descent.

It means that data teansfer rate goes down.

I think it is right that data tarnsfer is constant.

I would like to konw that why data transfer rate goes down during test.

Thanks!

sk
Anonymous
a b G Storage
August 8, 2005 7:37:57 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Previously pioioi <sk0105.yoon@samsung.com> wrote:
> Hi!~

> I'm testing Hard Disk performance with WinBench 99 Ver2.0.

> In the results, I wonder about Data Transfer Rate test.

> Data Transfer Rate result was represented graphically like curbe line
> of descent.

> It means that data teansfer rate goes down.

> I think it is right that data tarnsfer is constant.

> I would like to konw that why data transfer rate goes down during test.

Simple: There are more sectors on the outside than on the inside of
the disk, since the data density is an area limit. Since the disk
spins with constant speed you get lower data rates on the inner
tracks and most manufacturers place the sectors from outside to
inside. This fact is not hidden or secret in any way, every
manufacturer disk manual shows it.

Arno
Anonymous
a b G Storage
August 9, 2005 8:16:33 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

pioioi <sk0105.yoon@samsung.com> wrote

> I'm testing Hard Disk performance with WinBench 99 Ver2.0.

> In the results, I wonder about Data Transfer Rate test.

> Data Transfer Rate result was represented
> graphically like curbe line of descent.

> It means that data teansfer rate goes down.

> I think it is right that data tarnsfer is constant.

Nope.

> I would like to konw that why data transfer rate goes down during test.

The number of sectors per track varys in bands across the platters.
Since the drive spins at a constant rate, that means that the bands
which have more sectors per track move data faster because more
data moves under the heads at each revolution of the platter. That
is what determines the data thruput in a test that moves more data
than can fit in the cache on the physical drive.
!