said by aurgathor 
:For one thing, modern drives do not need a separate controller unlike the ST406/512 vintage since the controller is now part of the drive electronics. And as far as I know, in all cases, they are part software (firmware) and hardware, regardless of the interface.
Likewise, the host adapters are also part software and part hardware. Firmware is mandatory for SCSI (even for the simplest and cheapest one) but it may not necessarily be needed for a simple IDE HA, though nowadays all HA has some firmware.
I am not exactly sure the current trend of SCSI controllers these days (some are as cheap as $30.00). I stoped using them a few years back. I am kinda understanding why some newer controllers become part software and part hardware. I'll take your info at its face value for now, thanks for the info.
