Interesting drive behavior

[tp4tissue]

Why does it have a ramp like this at the beginning and end ?

did they cheap out on the head controller, so it's too fast at the beginning to track, and too slow at the end ?

start ramp from 150mb/s to 190mb/s

tail ramp from 100mb/s down to 83mb/s

[Leslieann]

Spinner?
Probably moving from outer area to inner, as well as having to frag more and more as it goes along.

[tp4tissue]

Spinner?
Probably moving from outer area to inner, as well as having to frag more and more as it goes along.

But this was continuous write, end to end.

[Leslieann]

Not sure how that matters.

[tp4tissue]

tested read only, end to end.

no dip. this is full read, not sampled

[Leslieann]

Looks like it tapered off to me.
Curve looks almost identical, different scale, but similar curve.

[tp4tissue]

yea, curve is the same, but no weird ramp

[Leslieann]

Minor stuff like that can be anything.
Some other system causing lag but my guess is that it was mapping out where to place all of the data.

[yui]

isn't the ramp cache optimization? or the drive spinning up from sleep and then slowing down at the end of copy? or if it is a magnetic shingle drive it will need to write 2 track at once to be fast, so at the end it could be that? all that is assuming hard drive, on and ssd there is not telling what the controller and windows are doing
i am throwing those out there because i am quite curious too

[Leslieann]

Shingle wouldn't write anywhere near these speeds, usually 1/4 normal speeds.

Could be drive spinup, I assumed the drive was already spinning (I never let mine spin down).