File Transfer speeds

I have just gotten my project to navigate the file system of one usb drive and copy any selected file to a second drive on a hub. I am able to copy files of about 200 kb in a few seconds using the file.copy(source file, dest file) command, however when I choose a larger file the transfer rate seems to slow down.

I know that obviously larger files take longer to copy, however the actual rate at which it is copying seems to slow down as well. I have a few general questions about whats happening?

  1. I can time how long it takes to get the data transfer rate but it would be useful if someone could tell me the transfer rate GHI says the FEZ is capable of.

  2. Does the domino support usb 2.0, if so it might be my hub is a low speed hub and possible I can change that.

  3. Would using a system like the cobra that has more memory speed up the file copying process?

  4. If I want to show a progress bar while a file is transferring is it a good idea to break the file up into bytes and copy them individually so I can calculate a percentage transfered and display that on a screen? Like would this make the whole thing much slower than using the regular file.copy command.

Sorry for all the questions, any help is appreciated.


  1. we see about 200KB so what you see is correct. Which is faster than we have expected it to be on a very small ARM chip :slight_smile:

  2. It is 2.0 compatible but the speed is 12mb. Going to 2.0 will not speed up anything since the processor will not be able to do anything faster that 200KB/sec…again, much faster than we had anticipated.

  3. Yes but slightly. Same as #2, the processor is 72Mhz 32-bit ARM so 200KB is well by the max the processor can do. More RAM will help with multiple files but in most cases you will not see speed difference.

  4. Never thought about this before and I am not file system expert so I do not have a good answer for this one :frowning:

Thanks for the response. I think it is pretty good for a small inexpensive processor like this too. :wink:

I will give it a go breaking up the file into pieces so i can display a progress bar. If it works i’ll post a response here with some transfer times and the code.