dba_hist_sysstat physical read , physical write

Hi,

In view dba_hist_sysstat  the value of  stat_name='physical reads' and physical writes  is it number of blocks reads and writes or IOPS ?

Please clarrify !

physical reads    11270057596

physical writes   167963168

I have two questions :-

1) Is it number of blocks reads and writes or IOPS

2) Is it logical read and write or physical ?

Thanks,

Mukesh