To warm-plug devices on a port 'idex':
# echo -n "1" > /sys/class/ide_port/idex/delete_devices
unplug old device(s) and plug new device(s):
# echo -n "1" > /sys/class/ide_port/idex/scan
done
NOTE: please make sure that partitions are unmounted and that there are no other active references to devices before doing "delete_devices" step, also do not attempt "scan" step on devices currently in use -- otherwise results may be unpredictable and lead to data loss if you're unlucky