When should we use "hdparm" ?

Hello,

We have some old system (2.4 kernel) which use hot swap with sata
(IDE) , bu using commands such as:
hdparm -U 0
hdparm -R 0 0x1f0 ...

But in newer system HW&SW we never use these commands when removing
and inserting sata.

Why was it used once and why is it not used in newer system ?
Is it that newer system do this somehow automatically ? Where ?is it
done, in SW or HW ?

Thank you,
ranran