C# - Create large files on USB FAST

When the Xbox 360 console formats a 1gb USB device, it adds 978mb of data to it in just 20 seconds. I can see the files on the USB and they are that size.

When I copy a file of the same length in Windows, it takes 6 minutes.

Maybe it is because Windows reads/writes, but the 360 just writes?

Is there a way to create large files like that on a USB with that kind of performance?开发者_Go百科 The files can be blank, of course. I need this writing performance for my application.

Most of the cmd tools I have tried have not had any noticeable performance gains.

It would appear that the 360 is allocating space for the file and writing some data to the file, but is otherwise leaving the rest of the file filled with whatever data was there originally (so-called "garbage data"). When you copy a file of the same size to the drive, it is writing all 978MB of, which is a different scenario and is why it takes so much longer.

Most likely the 360 is not sending 978mb of data to the usb stick, but is instead creating an empty file of size 978mb - yours takes longer because rather than simply sending a few KB to alter the file system information, you are actually sending 978mb of data to the device.

You can do something similar (create an empty file of fixed size) on windows with fsutil or Sysinternals "contig" tool: See Quickly create large file on a windows system? - try this, and you'll see that it can take much less than 20 seconds (I would guess that the 360 is sending some data, as well as reserving space for more). Note that one of the answers shows how to use the windows API to do the same thing, as well as a python script.

Could it be that the 360 is just doing some direct filesystem header manipulation? If a blank file is fine for you maybe you could try that?

It is all dependent on the throughput of the usb drive. You will need a high end usb such as the following: this list