fd(7)							 Miscellaneous Information Manual						     fd(7)

NAME

       fd - Floppy disk interface

SYNOPSIS

       controller      fdi0	  at *	  vector fdintr
       device disk     fd0	  at fdi0	drive 0
       device disk     fd1	  at fdi0	drive 1

DESCRIPTION

       The fd device driver and fdi controller make up the interface to %%CorpNameShort's integrated Floppy Disk Interface (FDI).

       If  the minor number is less than 64, the driver select number is indicated by bits 4 and 5, and the partition by bits 0 through 3.  If the
       minor number is one of 64, 65, 66, or 67, the drive select number is indicated by bits 0 and 1, and disk partitions are disabled.   In  the
       latter case, the entire surface of the media is treated as one large partition, and attempts to change the partition table fail.  The major
       number is 14 for both the block interface and the raw (character) interface.

   Legacy Device Names
       Refer to System Administration for an explanation of device naming.

       The legacy device names have the format rfd0, which indicates the raw device interface, or fd0p, which indicates the  block  interface  and
       where p indicates the partition using the characters a through h.  If you do not specify a partition with the block interface, partitioning
       is disabled.  Default file protection for /dev/fd0 is 666.

   Current Device Special File Names
       The current device special file names are /dev/disk/floppy, /dev/disk/floppy0c, and /dev/disk/floppy0a.	The  raw  current  device  special
       file  names  are  /dev/rdisk/floppy,  /dev/rdisk/floppy0c, and /dev/rdisk/floppy0a.  These device names are created automatically by dsfmgr
       when the system starts up.

   Interface
       The block interface is restricted to 512-byte, disk-sector aligned accesses. Reads or writes that attempt to start at the middle of a  sec-
       tor actually start at the beginning of the sector.

       There is no sector-boundary limitation if you use the raw interface.

       The driver protects the process that opens the floppy disk device from an accidental media change by preventing access to the device if the
       media is removed and then reinserted.  To access the drive after the media has been changed, either you must  close  and  then  reopen  the
       device,	or  you  must  issue a DEVIOCGET or FDIOTPRRST ioctl.  You can use the fddisk command with the -new option to issue the FDIOTPRRST
       ioctl.

       When a floppy disk device is first opened after changing media, a delay occurs while the partition table is read  from  the  media  if  the
       device  is  not of type rfd0 or /dev/rdisk/floppy0.  If the device is opened with FNDELAY, partition table reading may be delayed until the
       first actual read or write request.

       If you access media containing non-UFS data, the data on the media may appear to be a valid partition table.  In this case, the	user  will
       probably not be able to access the media.  To work around the problem, use the rfd0 device.

       Partitions a and c begin at physical sector 0 and occupy the entire disk.  All other partitions also begin at physical sector 0, but are of
       zero (0) length.  You can change partition sizes by using the disklabel command.

       The currently supported floppy disk drive is the RX26.  The supported media types in the RX26 are the 350DD of size 737280 (1440  sectors),
       350HD  of  size 1474560 (2880 sectors), and 350ED of size 2949120 (5760 sectors), as shown in the following partition layouts for the media
       types:

       RX26, Double Density:

		 disk	   start     length

		 dsk?a	   0	     1440
		 dsk?b	   0	     0
		 dsk?c	   0	     1440
		 dsk?d	   0	     0
		 dsk?e	   0	     0
		 dsk?f	   0	     0
		 dsk?g	   0	     0
		 dsk?h	   0	     0

       RX26, High Density:

		 disk	   start     length

		 dsk?a	   0	     2880
		 dsk?b	   0	     0
		 dsk?c	   0	     2880
		 dsk?d	   0	     0
		 dsk?e	   0	     0
		 dsk?f	   0	     0
		 dsk?g	   0	     0
		 dsk?h	   0	     0

       RX26, Extra Density:

		 disk	   start     length

		 dsk?a	   0	     5760
		 dsk?b	   0	     0
		 dsk?c	   0	     5760
		 dsk?d	   0	     0
		 dsk?e	   0	     0
		 dsk?f	   0	     0
		 dsk?g	   0	     0
		 dsk?h	   0	     0

   Ioctl Support
       Several special ioctls are defined  for	use  with  the	fd  device  driver.  Use  of  these  requires  that  /usr/include/sys/ioctl.h  and
       /sys/io/fd/mips/fdi.h are included.  See the fdi.h file for reference purposes.

       FDIOSENSE returns information about the current state of the drive via the structure fd_sense.  All elements of this structure are initial-
       ized by this call.  See comments in fdi.h for use of each element.

       FDIOGETMTYP returns information about the media currently in the drive via the structure fd_mt.	All elements of this  structure  are  ini-
       tialized by this call.  See comments in fdi.h for use of each element.

       FDIOFMTDSK,  FDIOFFBSETUP,  FDIOFFBNEXT,  and  FDIOFMTTRK are used for disk formatting.	Data is passed to and from these calls via certain
       elements of a structure of type fd_fmt_spec.  See comments in fdi.h for use of each element.  FDIOFMTDSK causes the entire disk to be  for-
       matted.	 FDIOFMTTRK causes a specified track to be formatted.  The combination of FDIOFFBSETUP and FDIOFFBNEXT cause the entire disk to be
       formatted, a little at a time, allowing the calling process to display an updated status line indicating the progress of the format.

       FDIOTPRRST causes the driver to ignore the fact that the media might have just been removed and reinserted.  Status information is returned
       via a fd_sense structure, just as with the FDIOSENSE call.

       FDIOSEEK  allows  the  user  to specify the position of the next single-sector access (and only the next access) in any of several formats.
       These formats include logical-sector-number format, physical-sector-number format, and  cylinder-head-sector  format.   These  formats  are
       specified in a structure of type fd_seek.  See comments in fdi.h for use of each element.

       FDIOMKCHS  and FDIOMKPSN are used to translate between cylinder-head-sector sector specification and physical-sector-number sector specifi-
       cation.	Data is passed to and from these calls via certain elements of a structure of type fd_chs_psn.	See comments in fdi.h for  use	of
       each element.

       The  calls  DEVIOCGET,  DEVGETGEOM, DIOCGETPT, DIOCDGTPT, and DIOCSETPT are also supported and perform in their expected manner.  A call to
       DEVIOCGET also has the effect of calling FDIOTPRRST.

FILES

RELATED INFORMATION

       Commands: disklabel(8),dsfmgr(8), mtools(1), dxmtools(1) fddisk(8), MAKEDEV(8), uerf(8) delim off

																	     fd(7)