Re: how to know a hard drive will mix well

On 02/02/2023 22:47, Pascal Hambourg wrote:

On 02/02/2023 at 19:52, Wols Lists wrote:

quoted

Drives now are "Constant Head Speed" not constant rpm. I'm guessing, 

Source ?

"Constant linear velocity" (CLV, as opposed to "constant angular 
velocity" - CAV) is adapted for use requiring a constant transfer rate 
such as media recording or playback, not random access, and is mostly 
found in optical disc drives.

quoted

that what it means is that for the inner tracks it spins at 7200, and 
as the heads move out, the rpms slow down to keep the speed the head 
is going over the platter constant.

It also implies that the spindle is able to accelerate from the lower 
speed (around 3600 RPM) to 7200 RPM or decelerate from 7200 to 3600 RPM 
in less than the full stroke time, which is around 20 ms in order to not 
degrade the access time. It sounds highly unlikely to me.

Just tried to Google it. Did I say I didn't trust WD?

It sounds like it's marketing speak designed to re-define the meaning of 
Revolutions Per Minute.

Apparently 7200rpm drives are being sold as "5400 class". Misleading 
people who are prepared to take the speed hit, into buying a drive that 
is power-hungry and noisy.

As the google page I saw said - "Why describe it as "5400-class" in a 
spec sheet - the people who don't know what it means won't be reading 
spec sheets, and the people who do read spec sheets won't know what the 
hell it means and it is deceptive".

I'd go and look for another X300, or an Ironwolf. At least you'll know 
what you're getting ...

Cheers,
Wol