awesome14 Loc: UK

Flash memory on SD-cards is much slower than even a HDD. When you use a USB<>SD-card adapter, or a card reader, the operating system writes the file names, and allocates the space on the SD-card while it's waiting for the actual content to be written.

All the file names are there, but with no contents in many of the files. The operating system goes into waiting, which puts the cpu in a wait state, during which time that particular cpu core can't do anything but wait while the data is written to the much slower Flash memory.

That usually doesn't matter, because only a few thousand wait states occur together. But when writing GBs of photos to a SD-card, you get millions of wait states all at once, and the time between when it looks like the data is written and when it really is written can be hours. Everything that can be done is completed, such as allocating space in the Flash memory, and writing the file names. The process to copy the files exits, and the operating system completes the writing in the background.

When you do anything with a computer, it uses a process to complete that task (actually many processes). When the task is complete, the process corresponding to it exits, or 'dies'. So, that is why it looks like the operation completes, when in actuality the files have not all been written. For 100GB transfer, wait at least an hour after you think it's done. Then try to access the files on the SD-card.

There are utilities available to show cpu wait % per core. I'm not sure what they are for Windows. You'd have to google it. In multithreaded operating systems, such as MacOS and Linux, the story is slighlty different, but not much. After the cpu has finished all its wait states, the data should all be written to the SD-card.

But you need the utility to actually see that the cpu is in stuck in a wait state! It is a design flaw in personal computers. MacOS and Linux have a program called 'sync'. If you run sync after the copy operation appears complete, when 'sync' exits, the job is actually done.

So, now you have two ways to check if the files have been copied.

graybeard

That was pretty much the key to all this. I will spell out what I found later, prolly tomorrow or next. Still wrapping up loose ends. I like your feedback, you do not posture like the cognoscenti nor change the subject about how moronic I am to even consider this. Stay tuned.

awesome14 Loc: UK

It's a gotcha that gets keeps many folks busy for weeks, until they give up. Flash drive manufacturers would sell a lot more drives if users were made aware of this very thing. USB<>SD-card adapters have no drive controller to speak of, so the SD-cards operate at a slow speed. If you want it to go faster, you can use MicroSD cards inside a mobile device that can accept such cards in a removable drawer.

You should connect the mobile device to a powered USB hub, so the phone can charge while you do your copying. Otherwise, it might go dead. The transfer rate with a typical mobile-device storage controller is 20-30x what you get with an USB<>SD-card adapter.

That's what I do if I'm in a rush.

CHG_CANON Loc: the Windy City

Oh well. Why do it easy, when you can attempt the (near) impossible? Why do it right, when you can do it wrong? Why do it fast, when you can waste a week doing it wrong? Is a USB drive really outside your universe of the possibly better, faster, and quicker options?

11bravo

As I posted earlier, the advantage of using TeraCopy with verify.

graybeard

This approach is wrong? I fail to see how. To me it is infinitely superior to any other. It is all between the camera and the computer. I can re-organize every picture I have on my cards any which way I care too. It opens up whole new vistas. Not that I am going to do this, I am, at least for the time being, happy to keep it limited to my slide projector idea. Of course, if you see no use for it yourself, you can ignore the whole idea.

graybeard

Oh, to answer to ? re a USB drive. I prefer using the permanently attached HDMI cable. Just plug it into the camera. But I must say I am disappointed at the often rude and nearly hostile response of some people to this. If it is not the way they care to do it, fine. Or is it because they hate being shown that their dogmatic inflexible and uninformed response what factually incorrect? This goes all the way up to Canon Tech Support, who should, after all, have known better. It amounts to a feature in their camera they weren't aware of !! In any case, I am always grateful for feedback, and I thank you for yours.

graybeard

So, you are one of the nay sayers. If you have been following this, you will have seen I have succeeded where you, and others, said I would not, should not, could not. I accept your apology which I know I will not get.