This is a 250 kilobaud data rate format, the maximum the WD-1773 FDC chip in the target machine can handle, with 18, 256 byte sectors per track, two sides=73728 bits to write a track, /250000 (baud rate)=0.294912 seconds to write one full tracks worth of data. 80 tracks=23.59296 seconds to write the whole disk if it were streaming, but it takes 3 minutes and change? And nearly 2 to read it back as above? Odd. With the interleave of 3, I could see 75 seconds maybe for efficient methods. I also understand this is a one size fits all scene too, and that there must be compromises.
I format these DD discs in the target machine with an interleave factor of 3 cuz that machines cpu is running at as low as .89MHZ and can't handle the read data any faster than that.
Is this non-1 interleave responsible for the slowness of the writes or reads on this box? I can control the interleave on the target box, so I suppose I could test that effect easily enough.