What's the purpose of the pins besides the SATA connector in a hard drive 3.5"?

[rodion15]

In older drives, these were for master/slave. In 2010 and 2011 iMac hard drives, this pins were a temperature sensor that is connected to the motherboard. I wonder what's the purpose in other non-Apple hard drives. I never saw these in 2.5" hard drives.

 

[SNGX1275]

They were used to make SATA II drives compatible with early SATA motherboards that could only do SATA I speeds AFAIK.