I'll have to make a bootable USB on OS X. To my great surprise, I found that the speed of copying with DD - otvratitelno low ~600KB/s 😕 . After a short search I found, what should I use rdiskX instead diskX. The idea is that rdisk is a synonym for raw device. Well from here I added one r blokovoe device to that of coper ISO then found that the speed is below ~150-200KB/s 😡 . Already mystics is complete and the previous information was confirmed from different sources!!!! Everything fell into place after I bs Directive.
bs=n Set both input and output block size to n bytes, superseding the ibs and obs operands. If no conversion values other than swab rearrange, notrunc or sync are specified, then
each input block is copied to the output as a single block without any aggregation of short blocks.
Once I put 1M size bs achieved speeds are expecting it to USB-me. Then tested the difference between disk and rdisk definitely the difference was about 10-12 once in speed in favor of rdisk. Very cultural way to control the speed and progress of dd can be achieved in the following Convair
sudo dd if=Downloads/path.to.iso bs=1M | pv | sudo dd of=/dev/rdisk2 bs=1M