On Wednesday 18 September 2019 11:36:41 John Hasler wrote: > Jonas writes: > > Please demonstrate just one single example of dd being faster than > > cp to transfer a full raw image to a raw device! > > On modern systems you would probably need to be doing terabyte > transfers between disks on the same machine. Back in the days when a > megabyte was a lot dd was *much* faster. > > On an SD card I think that the write speed of the card is probably the > limiting factor.
It is, and the makers lie a lot, taking advantage of the buffering to get thier 100 MBs rating for small writes. For gigabyte transfers I often see sub 20 MB/S toward the end. But you may want to steer clear of the 64GB+ cards, exfat is creeping into the sdhc arena, and I either have a defective NEW PNY 64GB, or this stretch install can't touch it because its exfat. I bought 2 recently, same exact part number, slightly different card gfx, the 85 meg rated one doesn't mention exfat, works, the 100 MB/S rated one mentions exfat and is untouchable. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene>
