We have a Bonded ADSL solution for our servers to provide the necessary upstream transfer speeds for the applications we host. We have bonded ADSL because our exchange still doesn't support SDSL, and a leased line is overkill. Theoretically, we should have 28.1 Mbps download and 3.2Mbps upload – what I am actually seeing is about 1.7Mbps down and 1.9Mbps up. I have tested this on various servers, over various times and file sizes, there is no doubt that the performance is POOR.
Anyway, on to my point. I wanted to create a file that was exactly 100MB to test transfer speeds. Windows XP, Vista, 2003 and 2008 all have a command line utility called FSUTIL.exe which has a subset of commands to manipulate files, with which you can create a file that is exactly 100MB…like so:
FSUTIL FILE CREATENEW 100MBTest.mdb 1048576
Usage: FSUTIL FILE CREATENEW [Filename] [Size in bytes]