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(fdutils.info)Adding new formats

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Adding new formats
==================

   You can redefine the default formats using the setfdprm program
(Note: setfdprm) (1).  The following example illustrates how to add a
new 19 sector format, and make a device entry for it.  First, we pick
an entry for it, which we want to reuse.  I recommend to redefine an
entry which is only rarely used.  For instance, if you have no 5 1/4
drive on your system, you can redefine any 5 1/4 entry without a loss.
In our example, we pick 10.

   First we make the device node:
     mknod /dev/fd0H1520 b 2 40
              ^          ^ ^  ^
              |          | |  Minor device number (format number * 4 +
              |          | |                       drive + controller*128)
              |          | Major device number (always 2!)
              |          Blockdevice
         A name that you choose for the format. I
         recommend to base the name on the capacity,
         but you may choose any name you want.

   Then we redefine the geometry of the new device:
     setfdprm /dev/fd0H1520 1520 19 2 80 0 0x1b 0 0xcf 0x6c

   *Note:* This redefines the geometry for any device node with the
same format number, not just the new node.

   The new geometry is only valid until the next reboot (or removal of
the floppy module).  In order to make it permanent, you have to execute
the `setfdprm' command from your `/etc/rc' file or whenever you insert
the floppy module.

   ---------- Footnotes ----------

   (1) In that case, the `MAKEFLOPPIES' program (Note: makefloppies)
no longer works to generate a correct name for these formats, and you
have to make them manually.