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    SubjectRe: floppy question of the hour
    Gene Heskett wrote:
    > 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.

    Yes, the interleave slows you down, since after accessing sector 1, the
    head must wait to pass over 3 other sectors before finally reaching
    sector 2, therefore, you can only read 1/4 of the sectors on the track
    each revolution of the disk. That leaves 4 revolutions at 300 rpm
    giving 0.8s to read a track, or 64 seconds to read all 80 tracks, plus
    seek time. That still does not explain 3 minutes though... not sure
    what else could be slowing you down.

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