Marcel:


   There are a couple of things that are limiting the speed of the sound
   files:

   1.  Raw transfer rate of the disk controller. The hardware is set up to
   read the data at 500 kbps (for 1.44MB formatted disk, 2MB unformatted).
   To transfer 11.52 megabits (1.44MB) would require 23 seconds, but the
   data coding is not one-for-one, and there are "wasted" gaps between
   sectors.  So, the absolute minimum transfer time due to this constraint
   would be 32 seconds or so.

   2. Head Access time. The drive head takes a finite amount of time to
   move. Typically this is pretty slow (compared to a hard drive), and if
   i'm not mistaken it takes about 1/3 of a second to move 1/2 of the full
   range of motion (or is it 1/3 of a second for the full range of motion?).
   Anyway, if this is the problem (you can hear it grind away), you might
   try defragmenting the disk. Since the sythesizer probably doesn't have
   this function, format a new disk and copy the files you need onto it.
   Defragmenting (should) only become a problem when you start deleting
   stuff off the disk

   3. Spin-rate access time. (also known as interleaving). The computer has
   to wait for the sector to physically spin under the head. If the
   interleave is set right, then when the computer is ready to read the next
   sector, it will be just about at the head. If the interleave is bad then
   the sector will have just passed the head and the computer will have to
   wait until it comes around again.
   -------------

   Factor 1 will definately limit the speed you can push this to without
   changing firmware. You might be able to change it just a little (or do
   some hardware work) to re-set the floppy controller for 1 Mbit/sec
   (2.88Meg) or even 2 Mbit/sec (5.76Meg). The floppy controller in my
   laptop supports these functions, but the 2 Mbit/sec is untested.

   Factor 2 you might be able to speed up; the keyboard may delay a fixed
   time after it commands the floppy to change sectors (bad), or it might
   just start looking for data whenever it gets there

   Also remember that floppy disks aren't encoded in a one-bit-to-one-bit
   correspondence.

   PICS might have a problem with the all of the access lines requried for
   the IDE harddrive interface. Then they have to be able to store a
   sector's worth of data, which could be tough. They have to generate the
   MFM encoding and the CRC.

   It's all possible, but there is a limit to how fast this aproach will get
   you (32 seconds+) and it would be a lot of work. It might be easier to
   hack into the ROM chip of the synthesizer and re-write the floppy
   read/write routines to access a hard disk. The harddisk would have to be
   put on the processor's bus, or through a serial port (the MIDI
   interface?!) to a PIC controlling it. All of this, however, may void your
   warranty . . .


   John Maushammer
   jmaushammer@SMTPLINK.CTA.COM