The specified data transfer rate or read speed of the device is the rate at which it transfers user data off it medium period end of research I don t think we should be confusing the article by using anything else The fact that some early FD controllers system buses and or device drivers could not even support the FDD data rate necessitating interleave is irrelevant to this specification Likewise the loss of performance due to file fragmentation and or low level formatting is also irrelevant to this specification I suppose a discussion on specified data transfer rate versus net data transfer rate might be interesting but it applies to all disk media so I am not sure such a discussion in the FD article is appropriate I haven t done the math to see if the specified data rate of any FDD is 1 1 6 that of the single speed CD but that would not surprise me