QEMU -hda file.img is /dev/sda in Linux?
The -hda option emulates a PATA disk. At around 2006, Linux switched to a different kind of PATA drivers – the new ones were written using LibATA to make the disks appear as if they were SCSI devices, and therefore use sd names instead of hd.
(In fact, the "old style" IDE drivers were completely removed from Linux just this week and LibATA is the only method that remains.)